Reference

NBSIR 84-2910

Field Evaluation of SPT Energy,

Equipment, and Methods in Japan

Compared With the SPT in the

United States

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Technology

Center for Building Technology

Gaithersburg, MD 20899

August 1 984

U.S. DEPARTMENT OF COMMERCE

-QC100

,1156

34-2910

1934

NATIONAL BUREAU OF STANDARDS

NATIONAL BUREAU

OF STANDARDS DENARY

NBSIR 84-2910

FIELD EVALUATION OF SPT ENERGY,

EQUIPMENT, AND METHODS IN JAPAN

COMPARED WITH THE SPT IN THE

UNITED STATES

William D. Kovacs

Lawrence A. Salomone

U S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Technology

Center for Building Technology

Gaithersburg, MD 20899

August 1984

U.S. DEPARTMENT OF COMMERCE, Malcolm Baldrige, Secretary

NATIONAL BUREAU OF STANDARDS. Ernest Ambler. Director

PREFACE

The study presented in this report was initiated, planned, and executed as a joint research program within the purview of the U.S. -Japan Panel on Wind and

Seismic Effects.

A Standard Penetration Test (SPT) program was carried out in Japan over a one month period beginning October 16, 1983. Participation of the field work

included personnel from the National Bureau of Standards and the Bureau of

Reclamation on the U.S. Side and the Public Works Research Institute of the

Ministry of Construction and 0Y0 Corporation on the Japanese Side.

This report contains the following information as a result of the study: a)

U.S. and Japanese practices on the Standard Penetration Test, b) comparison of

U.S. SPT and Japanese SPT test results, and c) comment on SPT liquefaction

design curves with respect to the Japanese data base.

A number of organizations and individuals contributed to the success of this

study. Funding for this study was provided by the National Bureau of

Standards, the Bureau of Reclamation, the National Science Foundation, the

Naval Facilities Engineering Command, and the Waterways Experiment Station.

The joint program coordination and support in Japan were provided by Dr. T.

Iwasaki and Mr. Y. Sasaki of the Public Works Research Institute, and Dr. K.

Suyama and Mr. Ohya of 0Y0 Corporation. Their contributions are greatly

appreci ated.
ABSTRACT

Field energy measurements on Japanese drill rigs were made during the performance

of the Standard Penetration Test to document the difference between Japanese

and present U.S. practice. A total of 78 Standard Penetration Tests were

performed using 19 different testing conditions (equipment and operators).

Over 2,200 data points are reported.

Results from this investigation show less scatter than U.S. data and the average

value for ER ^ (the ratio of the energy passing through the drill rod to the

theoretical free-fall energy) using Japanese equipment and operators is 68

percent with a standard deviation of 9.6 percent. Considering only energy

and sampler effects, the ratio of U.S. blow counts to Japanese blow counts

(Nus/Nj) is 0.98 (variation between 0.72 and 1.80) when the cathead and

rope method was used as the hammer release mechanism and using ERy$ equals

55 percent and ER

j equal to 67.4 percent. When the Tombi method (free-fall) was used, the ratio of Nu$/Nj is 1.17 (variation between 0.86 to 2.15)

when ERUS equals 55 percent and ERj equals 80.4 percent. It was found

that the Japanese use bottom discharge drill bits and an SPT sampler with a constant inside diameter of 1-3/8 in (35 mm) in contrast to U.S. procedures

and equipment. A shape factor to account for differences in sampler is

presented.

Keywords: Energy measurement, field testing, in situ testing, liquefaction

potential, soil mechanics, SPT, Standard Penetration Test.

IV
EXECUTIVE SUMMARY

Field energy measurements were made in Japan during the performance of the

Standard Penetration Test (SPT) (ASTM D 1586) to document how the Standard

Penetration Test is performed and used in present Japanese engineering practice

and to compare the Japanese SPT results with those found in the United States.

The field studies were conducted over a 1 month period beginning October 16,

1983, at three Japanese locations. The first location, north of Akita, con- sisted of three separate drilling sites in which the potential energy, the

kinetic energy at impact, and the energy transmitted through the drill rods were measured during the Standard Penetration Test. Both the American Society

for Testing and Materials (ASTM) and the Japanese Industrial Standard (JIS)

samplers were used. At the second location at Niigata, tests similar to those

in Akita, were performed in three borings. Two sites in an earthquake area that liquefied and one site in an area that did not liquefy were chosen for

the in situ tests at Akita and Niigata. Nine additional sites in the TokyoYokohama area were also selected to obtain a better representation of the

performance of drill rigs used in Japan. At the three locations, a total of

78 individual Standard Penetration Tests were performed using 19 different

testing conditions (equipment and operators) with approximately 2,215 individual

data points.

The primary energy measuring system which measured the energy passing through

the drill rod consisted of an SPT Energy Calibrator, integration timer, oscilloscope, and a load cell that was mounted in the drill rod at least 10 drill

rod diameters below the point of hammer impact. The secondary energy measurement system which measured the potential and kinetic energy of the hammer

consisted of a black and white target mounted on the SPT hammer, light beam

scanners that record the passage of the hammer during its rise and fall, and

the signal conditioning required for the scanners. Two tape recorders were

also used to record information from the Calibrator and to provide a permanent

record of the force-time curve, integration time, and output from the top and

bottom scanners.

The Japanese drill rig equipment consisted of either a wooden or a steel tripod

placed over a portable drilling machine used to perform wash borings. A rotary

wash drilling method utilizing a bottom discharge bit and drilling mud was

used to advance the hole.

The Standard Penetration Test in Japan is performed in accordance with the

Japanese Industrial Standard (JIS) A 1219-1961 (reaffirmed 1978). This standard fixes the size of the SPT sampler to a 2 in (51 mm) outside diameter and

an inside diameter of 1-3/8 in (35 mm) throughout its length. Anvils (knocking

heads) 3 inches in height and diameter are also required. A 1.6 in (40.5 mm)

drill rod was used throughout the testing program. Either the cathead and

rope method or the Tombi method (free-fall) was used as the hammer release

mechanism. The catheads on the Japanese rigs typically ranged in length from

3 to 6 inches (75 to 150 mm) and many of them had curved surfaces with maximum

diameters approximately 8 in (203 mm) and with minimum diameters of approximately 4.3 in (109 mm). Cathead speeds varied between 60 and 300 rpm, depending on the operator.

v
Results from this investigation are presented in terms of the ratio of the

energy passing through the drill rod during the first compression wave pulse

to the theoretical free-fall energy assuming a 762 mm (30 in) fall (ER-j )

.

Comparing the range of ER-j values in Japan with those of the United States,

one finds that the Japanese data exhibit less scatter than the U.S. data.

The average value for ER-j using Japanese tests is 68 percent with a standard

deviation of 9.6 percent. This figure includes energy ratio results using the

cathead and rope and the Tombi method as the hammer release method. If the

data for each of the hammer release mechanisms are treated separately, the

average results for ER-j for the cathead and rope and the Tombi method are 67

percent and 80 percent, respectively. The average value for ER-j using data

from U.S. tests is approximately 55 percent which includes all published

cathead and rope data with the ASTM sampler without liner.

The number of turns of rope around the cathead and rope age had little effect

on ER-j in Japan in contrast to U.S. experience. The effect of sampler type on the standard penetration resistance, N, was found to be significant. On the

average blow count values (Nj) obtained using the J IS sampler were found to

be approximately 25 percent greater than blow count values obtained using the

ASTM sampler.

For the cathead and rope method, and considering only energy and sampler

effects, the ratio of U.S. blow counts to Japanese blow counts (Nys/Nj) is

0.98 (with a variation of 0.72 to 1.80) considering the energy and samplers

used, and the average values of U.S. and Japanese energy of 55 and 68 percent,

respectively. When the Tombi method was used, the ratio of Nys/Nj was 1.17

(with a variation between 0.86 and 2.15. Because of this variability in the

ratio of Nys/Nj, it would be prudent to reexamine the design curves used

to evaluate liquefaction potential considering this variation.

This study also showed Japanese practice produces a rate of blow application

only about 1/3 that in U.S. practice. The Japanese also use drilling mud and

bottom discharge methods to advance the hole, which the ASTM has successfully

prohibited in U.S. practice. These effects, and perhaps others not yet

identified, may have significant importance and remain not studied to date.

vi
TABLE OF CONTENTS

Pa^e

PREFACE iii

ABSTRACT i v

EXECUTIVE SUMMARY v

LIST OF FIGURES ix

LIST OF TABLES xi

NOTATION xi

i

1. INTRODUCTION 1

1.1 Purpose 1 1.2 Scope 1 1.3 Background 1

2. EQUIPMENT USED IN THE STUDY 5

2.1 Drill Rig Equipment 5 2.2 SPT Equipment 5 2.3 Energy Measurement Equipment 6

3. PROCEDURES 10

3.1 Drilling Procedures 10

3.2 SPT Procedures 10

3.3 Energy Measurement Procedures 11

3.4 Data Reduction Procedures 12

4. DRILLING AND TESTING SITES 13

4.1 Introduction 13

4.2 Akita Sites 13

4.3 Niigata Sites 13

4.4 Tokyo Sites 14

5. SPT RESULTS 22

5.1 General 22

5.2 Presentation of Energy Ratio Results, ER-j (Percent) 22

5.3 Presentation of ER-j vs Depth

5.3.1 Introduction 23

5.3.2 Akita Sites 23

5.3.3 Niigata Sites 24

5.3.4 Effect of Sampler Type on N-Value 24

vi i
TABLE OF CONTENTS (Continued)

Page

6. APPLICATION 48

6.1 Comparison of Japanese ER-j and United States ER-j 48

6.2 Evaluation of the Ratio of Ny$/Nj Taking into Account Energy

Ratio and the Sampler Shape Factor 48

6.3 Evaluation of Japanese Data Base and Effect on Present

Engineering Design Curves for Liquefaction Potential 49

7. FINDINGS 51

8. CONCLUSIONS 52

9. ACKNOWLEDGMENTS 53

10. REFERENCES 54

vi i i
LIST OF FIGURES

Page

Figure 1. Tripod over portable drilling machine used in Japan for

performing the SPT 7

Figure 2. Two drilling tools with hardened steel cutting edges and the

open bottom discharge bit 8

Figure 3. Energy measurement equipment in field shock proof case: SPT

Calibrator, timer, and oscilloscope 9

Figure 4. SPT study region in Japan. Sites A through L (from 0Y0

Corp.) 15

Figure 5. Guide map of the Akita area (from 0Y0 Corp.) 16

Figure 6. Bore hole testing arrangement at the Akita sites (from

0Y0 Corp. ) 17

Figure 7. Guide map of the Niigata area (from 0Y0 Corp.) 18

Figure 8. Bore hole testing arrangement at the Niigata sites (from

0Y0 Corp. ) 19

Figure 9. Detailed Map of the Kawagi shi-cho site in Niigata (after

Ishihara and Koga, 1981) 20

Figure 10. Guide map of the Tokyo area (from 0Y0 Corp.) 21

Figure 11. Summary of ER-j data vs N-value by operator 29

Figure 12. Frequency diagram of ER-j results 30

Figure 13. Energy ratio variation by operator 31

Figure 14. ER-j vs N-value showing effects of number of turns of rope

around the cathead 32

Figure 15. ER-j vs number of rope turns around the cathead 33

Figure 16. ER-j vs N showing the effect of rope age using 1-3/4 turns of

rope around the cathead 34

Figure 17. N-value vs depth profile for the Akita area: a) borings A-l

and A-2, b) borings B-l and B-2, and c) borings C-l and C-2 . 35

Figure 18. N-value vs depth profiles for the Niigata areas: a) boring

D-l and b) boring D-2, Kawagi shi-cho site

:i x
LIST OF FIGURES (Continued)

Page

Figure 19. N-value vs depth profile for the Kawagi shi-cho site in

Niigata (after Ishihara and Koga, 1981) 40

Figure 20. N-value (uncorrected for Energy Ratio) vs depth compiled

from figures 18a, 18b, and 19 41

Figure 21. N-value vs depth for boring E-l, the left bank of the Showa

bridge site, liquefied site 42

Figure 22. N-value vs depth for Showa bridge no. 2, liquefied site

(after Iwasaki et al . , 1978) 43

Figure 23. N-value vs depth for boring F-l, the Right Bank of the

Showa bridge, a non-1 iquef ied site 44

Figure 24. N-value vs depth for Showa bridge no. 4, a non-liquefied

site (after Iwasaki et al., 1978) 45

Figure 25. N-value correlation between JIS and ASTM samplers,

normalized to average Energy Ratio of 68 percent, direct

measurement data 46

Figure 26. N-value correlation between JIS and ASTM samplers, direct

measurement data and data obtained from interpolation 47

x
LIST OF TABLES

Page

Table 1. Tabulation of Results and Test Conditions. Steel guide pipe

unless mentioned; rotary wash w/mud and casing 26

Table 2. Summary of Direct Measurement Data Comparing Ny$ and Nj 27

Table 3. Summary of Regression Analyses 28

Table 4. Summary of Blow Count Ratios, Ny$/Nj for Different Assumed

Energy Ratio Conditions 50

xi
NOTATION

E-j = Energy passing through the drill rod as measured from the first

compression wave pulse.

E* = The standard potential energy specified for the Standard Penetration

Test (SPT) , 4200 in-lbs (475 J).

ei = E v /E*, the efficiency of the rope hammer pulley system which depends on the number of turns of rope around the cathead, rope age, drill rig

geometry, and probably other factors not specifically identified that

may include cathead speed and diameter and operator characteristics.

e£ = E-j/Ey, the efficiency of the hammer-anvil system in transferring

energy to the drill rod; also known as the energy transfer ratio, ETR.

E v = The kinetic energy of the hammer just before impact.

ER-j = Ratio of the energy passing through the drill rods observed from the

first compression wave pulse to the theoretical free-fall energy assuming

a 30 i n (762 mm) fal 1

ERj = Energy ratio in Japan.

ERys = Energy ratio in the U.S.

N = SPT blow count or penetration resistance in blows per foot over a

6 to 18 in (15 to 45 cm) penetration interval.

N cj = Blow count using the cathead and rope method in Japan.

N-tj = Blow count using the trip monkey (Tombi method) in Japan.

Nc f

= N- value using cathead and rope method outside of Japan.

Nj = SPT blow count or penetration resistance in blows per foot obtained

using Japanese operators, equipment, and procedures.

Nys = SPT blow count or penetration resistance in blows per foot obtained

using U.S. operators, equipment, and procedures.

Ngg = SPT blow count normalized to an energy ratio (ER-j) of 68 percent.

S = Sampler shape factor.

Sj = Japanese sampler shape factor.

Sys = U.S. sampler shape factor.

XI 1
1. INTRODUCTION

Field energy measurements on Japanese drill rigs were made during the

performance of the Standard Penetration Test (SPT) (ASTM D-1586). The field

studies were conducted in Japan over a 1 month period beginning October 16,

1983. The measurements were taken at three different general locations. The

first location, north of Akita, consisted of three separate drilling sites in

which data on the hammer potential energy, the hammer kinetic energy at impact,

and the energy passing through the drill rods were collected during the Standard

Penetration Test, using the ASTM and Japanese Industrial Standard ( J IS A1219-

1961) samplers. Two sites in an area that liquefied during the 1983 Northern

Japan Earthquake and one site in an area that did not liquefy were chosen for

the in situ tests at Akita. A total of 958 data points (blow counts) were

obtained at the Akita sites using three types of SPT hammers typically used

in Japanese engineering practice.

The second location was at Niigata and it was tested in a similar manner with

three borings. Two borings were in an area that liquefied and one boring was

in an area that did not liquefy. In Niigata extensive liquefaction occurred

throughout the city during the 1964 earthquake. By performing Standard Penetration Tests at known liquefaction and nonliquefaction sites, as in previously

documented studies, the SPT energy on which present liquefaction potential

design procedures are based can be estimated. A total of 639 data points were

obtained at the Niigata sites.

Nine additional sites in the Tokyo-Yokohama area were also selected to obtain

a better representation of drill rigs used in Japan. Six hundred eighteen

(618) data points were obtained in the Tokyo-Yokohama area.

A total of 78 individual Standard Pentration Tests were performed using 19

different testing conditions (equipment and operators) with approximately

2,215 individual data points being reported.

1.1 PURPOSE

The purposes of this study are: 1) document how the Standard Penetration Test

is performed and used in present Japanese engineering practice, 2) compare the

Japanese SPT results with those found in the United States, and 3) comment on the SPT liquefaction design curves with respect to the Japanese data base.

1.2 SCOPE

The energy in the drill stem of Japanese SPT equipment was measured using ASTM

and JIS samplers. This information was used to compare U.S. and Japanese blow

counts.

1.3 BACKGROUND

Traditionally, the blow count, N, obtained from the Standard Penetration Test

has been a major tool in the evaluation of liquefaction potential or cyclic

1
mobility of sandy sites. Available Japanese SPT data form an important part

of the information base that was used to develop the SPT design curves to

evaluate liquefaction potential (Seed et al . , 1983). There is evidence that

the SPT results obtained in Japanese practice differ from those in U.S. practice.

Kovacs et al . (1983) have shown that variations in the energy passing through

the drill rod constitute a major problem in U.S. SPT practice. The energy is

affected not only by the hammer release mechanism, operating procedure, and

operator characteri sties, but also by the type of hammer and anvil used.

Thus, it is necessary to reference the design curves used in liquefaction

studies to a specific energy level. Japanese SPT practice as specified in

Japanese Industrial Standard ( J IS ) A 1219 differs from U.S. practice and there

is a difference between the U.S. and Japanese sampler. Thus, it is also

necessary to estimate a correlation between U.S. and Japanese practice and to

ascertain whether Japanese data points were accurately considered when the

design curves were established. It will then be possible to calibrate the

rigs used in field exploration on safety-related projects and, if necessary,

correct the blow count to account for the difference between the energy level

assumed in the design curves and that obtained in the field.

Schmertmann and Palacios (1979) concluded that the energy reaching the sampler,

E-,- , is inversely proportional to the blow count, N. Hence, the energy passing

through the drill rod that reaches the sampler must be known to compare blow

counts.

The energy passing through the drill rod in the SPT can be expressed by

the following equation:

E-j = E**e^»e2 (1)

where E-j = energy passing through the drill rod,

E* = the standard potential energy specified for the SPT = 4200 in-lbs

(475 J),

e\ = E v /E*, the efficiency of the rope hammer pulley system which depends

on the number of turns of rope around the cathead, rope age, drill

rig geometry, and probably other factors not specifically identified

that may include cathead speed and diameter, and operator

characteri sties,

e2

= E -j /E v , the efficiency of the hammer-anvil system in transferring

energy to the drill rod; also known as the energy transfer ratio,

ETR,

E v= the kinetic energy of the hammer just before impact;

The efficiency of the rope/hammer/pul 1 ey system has been estimated to average

approximately 68 percent (ei = 0.68) in typical U.S. practice (Kovacs et al .

1981, 1983). The Japanese practice of throwing the rope off the cathead should

result in an increase in the velocity of the falling hammer just before impact

as compared to present U.S. practice where the rope is not thrown off. It was

2
initially estimated that the energy loss in Japanese practice is no more than

one-half the energy loss in U.S. practice. This would produce a kinetic energy

at hammer impact of 84 percent of the standard energy (ei = 0.84).

Recent field tests have shown that the Japanese type SPT donut hammer is more

efficient than the U.S. safety hammer. On March 7 and 8, 1983, Purdue

University, in collaboration with the National Bureau of Standards (NBS), con- ducted field tests on a variety of SPT hammers which included a donut (type)

hammer and anvil (knocking head) machined according to the dimensions of the

Japanese SPT Standard (Japanese Industrial Standard, J IS A 1219-1961,

reaffirmed: 1978) , and which were dropped by free fall to eliminate the variable

ei = 1.0). In addition, the drill rod specified in J IS A 1219 [1.6 in

0D (40.5 mm)] was approximated by using AW rods [1.75 in 0D (44.5 mm 0D)]. In

accordance with these tests, the average of 10 drops of the Japanese donut

hammer produced an e2 of 0.76 with a coefficient of variation of 3.5 percent.

This compares with an estimated average for e2 of 0.65 for all U.S. hammers

published to date (Kovacs et al . , 1983),

It appeared from this information, that in typical Japanese practice using

donut type hammers, ei • e 2 = 0.64, while in U.S. practice ei • e 2 on the

average is only 0.44 (Kovacs et al . , 1983). Including safety hammers, the efficiency of U.S. rigs was found by Kovacs et al . (1983) to average approximately

0.55, which is still less than the efficiency of Japanese equipment. This

difference between U.S. and Japanese equipment and procedures is significant

and must be considered when liquefaction data are interpreted.

Tokimatsu and Yoshimi (1983) have shown statistically that the SPT N-value by

the cathead and rope method in Japan is greater by about 20 percent than the

trip monkey (free-fall) or Tombi method for any N-values up to about 40. Thus,

they proposed the following relation for converting blow counts from one method

to blow counts for the other method.

N cj - 1.2 N t j

( 2 )

where cj means cathead and rope method in Japan, and tj means trip monkey in

Japan.

Tokimatsu and Yoshimi also proposed a relationship for interpreting the SPT

N-values from other countries besides Japan according to eq. (3).

N cf = 1.4 N t j (3)

where cf means cathead and rope method in other countries.

Another source of difference is the sampling spoon used. Equation (3) did not

take into account the effects of sampler shape. SPT samplers used in the U.S. are constructed in accordance with ASTM D 1586 and have an inside diameter of

1-3/8 in (35 mm) for the cutting shoe and an inside diameter of 1-1/2 in

(38 mm) for the barrel. The 1/16 in (1.6 mm) recess in the barrel is for a liner, which in most instances is not used in current practice. Without the

liner, the friction is reduced. According to Schmertmann (1979, 1980), this

3
could account for a 10 to 30 percent reduction in N values in sands. Japanese

samplers do not have the recess for liners. When comparing U.S. and Japanese

rigs, an additional correction will have to be made to account for the difference in sampler configuration. The correction for the sampler will be discussed

1 ater.

4
2. EQUIPMENT USED IN THE STUDY

2.1 DRILL RIG EQUIPMENT

The Japanese drill rig equipment consisted of either a wooden or steel tripod

placed over a portable drilling machine used to perform wash borings. These

drill rigs have the capacity to drill to approximately 300 ft (91 m). Fig- ure 1 shows a typical tripod over a portable drilling machine performing

Standard Penetration Tests. The catheads on these rigs normally range in

length from 3 to 6 in (76 to 152 mm) and many of them have curved surfaces

with maximum diameters approximately 8 in (203 mm) with minimum diameters of

approximately 4.3 in (109 mm). Typically, the cathead speed varies between 60

and 300 rpm, depending on the operator. Figure 2 illustrates two typical

drill tools with hardened steel cutting edges and open bottom discharge bit.

The hole is advanced using a driller and an assistant operator.

2.2 SPT EQUIPMENT

The Standard Penetration Test in Japan is generally performed in accordance

with Japanese Industrial Standard ( J IS ) A1219-1961 (reaffirmed 1978). This

standard fixes the size of the SPT sampler to a 2 in (51 mm) outside diameter

and an inside diameter of 1-3/8 in (35 mm) throughout its length. In addition

to the J IS sampler, an ASTM sampler was used in 28 of the Standard Penetration

Tests. Typical drill rod sizes have been surveyed by Yoshimi and Tokimatsu

(1983). For this study, a 1.6 in (40.5 mm) drill rod was used throughout the

testing program. The cross-sectional area assumed for the drill rod is 0.827

sq in (534 sq mm) (Tsuneaki Iwasaki , private communication, October 18, 1983).

The U.S. AW drill rod is 1.75 in (44.5 mm) 0D by comparison.

Several types of cylindrical, i.e., donut-shaped hammers were used during the

study. A typical donut hammer is shown in the top of figure 1. The hammers

are assumed to be 140 lbs (63.5 kg) and vary in height from 10-1/2 in (267 mm)

to 13-3/4 in (349 mm). The outside diameter of the hammers varied from 7 to

8 in (178 to 203 mm) while the inside diameter of the hole varied from 1.6 to

2.0 in (40.5 to 51 mm). The truncated cone hammers which were used three

times were approximately 16 in (406 mm) in height and varied from 6 to 8 in

(152 to 203 mm) in top and bottom outside diameters, respectively, with a 2 in

(51 mm) inside diameter hole. In some cases, a reinforcing bar was welded to

the eyelets and inclined at a 45 degree angle from the horizontal for attachment of the cathead rope. The remaining hammers used had chains to operate

the hammer as a falling weight during the test.

The anvil used in the performance of the SPT differs substantially from typical

practice in the United States where a more massive piece of steel is used.

Anvils varied from 3 to 3.5 in (76 to 89 mm) in diameter and from 2.1 to 3.4

in (53 to 86 mm) in height. The Japanese Industrial Standard A1219 requires a height of 3 in (76 mm) and a diameter of 3 in (76 mm).

5
2.3 ENERGY MEASUREMENT EQUIPMENT

The primary energy measuring system consisted of the SPT Energy Calibrator,

integration timer, and an oscilloscope (figure 3). The Calibrator measures

ER-j , the ratio of the energy passing through the drill rods observed from the

first compressive wave pulse to the theoretical free fall energy assuming

a 30 in (762 mm) fall, expressed as a percentage. Not shown in figure 3 is

the load cell that connects into the SPT Calibrator and which is mounted in

the drill rod at least 10 drill rod diameters below the point of impact. A

further description of the SPT Calibrator is given by Hall (1982) and Kovacs

et al . (1983). The timer is connected electrically to the oscilloscope output

of the SPT Calibrator to provide a digital readout of the integration time.

The integration time should approximate the return time for the compressive

wave to pass through the load cell and return as a reflective tensile wave

from the bottom of the sampler. A second connection from the SPT Calibrator

goes to the oscilloscope where the wave form and the integration time may be

monitored visually.

The secondary energy measurement system (e.g., Kovacs et al., 1983) consisted

of a black and white target mounted on the SPT hammer, the light beam scanners which record the passage of the hammer during its rise and fall and the signal

conditioning required for the scanners. Two tape recorders were also used

to record information from the Calibrator readout devices and to provide a permanent record of the force-time curve, integration time, and output from

the top and bottom scanners. Figure 1 shows the bottom scanner, that is mounted

exactly 30 in (762 mm) from the top scanner (not shown), attached to a piece

of lumber adjacent to the hammer during the performance of the SPT.

6
Figure 1. Tripod over portable drilling machine used in Japan

performing the SPT

for

7
Figure 2. Two drilling tools with hardened steel cutting edges and the

open bottom discharge bit
AjVs

Figure 3. Energy measurement equipment in field shock proof case:

SPT Calibrator, timer, and oscilloscope

9
3. PROCEDURES

3.1 DRILLING PROCEDURES

A rotary wash drilling method utilizing a bottom discharge bit and drilling mud

was used to advance the hole. A steel casing 4 in (10.2 cm) in inside diameter

was frequently driven to seal off the upper layers and provide a non-erodable

outlet for the drilling mud. Below the cased hole the diameter of the uncased

hole was approximately 2.5 in (6.5 cm). The drillers estimated that the rate

of flow of the drilling fluid through the bottom discharge bit to be approximately 8 to 11 gallons per minute (30 to 40 liters per minute). When the

desired depth to perform the SPT test was obtained, the drill rig operator

assured that the hole was cleaned out, the pump shut off, and the drill rods

withdrawn. Generally the drilling procedures followed during this study were

those described by Hvorslev (1949) and by the Department of Interior, Bureau

of Reclamation (1974) except that a bottom discharge bit was used. However,

it should be pointed out that the fluid level was not maintained when the

drill rods were withdrawn. This practice and the use of bottom discharge bits

could result in lower blow counts. Parsons (1966) noted that the fluid level

is not often maintained in the U.S. either.

3.2 SPT PROCEDURES

With the drill hole cleaned out, and the rods withdrawn, an SPT sampler was connected to the bottom of the drill stem and reinserted into the boring to

the desired depth. A check was made to ensure that the bottom of the sampler

was within 2.4 in (60 mm) of the bottom of the hole. Generally, the Standard

Penetration Test was run with the rods inside the rotating kelly of the drill

rig. However, in some instances, it was impossible to install a load cell and

allow sufficient penetration of the sampler because of interference with the

drill rig. Consequently, it was necessary to perform the SPT with the kelly

removed from over the drill hole.

On many of the drill rigs, the operator had the choice of a top or bottom

cathead. In the cases tested and observed in Japan, the rotation of the

cathead was such that the top of the cathead rotated toward the operator and

as a result, the number of turns was generally less than the nominal turns by

1/4 of a turn. For example, many operators used 3/4 of a turn and 1-3/4 of a turn to perform the SPT. On certain occasions, operators made an effort to

throw the rope completely off the cathead during the downstroke of the hammer.

Because of these procedures, the rate of testing was from 7 to 25 blows per

minute with an average of approximately 15 blows per minute, substantially

less than that of American practice of 30 to 60 blows per minute. The slower

rate of performing the SPT was due to the method of rope release as well as the drill rig operators' desire to provide a fall height as close to the

required 30 in (762 m) fall as possible. Many of the operators used what is

termed the “hold-drop" procedure wherein the operator raises the hammer until

the bottom of the hammer is just at the 30 in (762 mm) mark above the anvil

and then releases the rope as quickly as possible. The operators were extremely

careful to obtain the required drop height before quickly releasing the hammer.

The above procedure was used with the cathead and rope approach. For some

10
tests the Tombi method was used wherein either type of hammer (donut shaped or truncated cone shaped hammer) was released by a metal hook. This procedure

allowed essentially free-fall of the hammer independent of the drill rig and

operator.

The operator counted the number of blows that the sampler penetrated every

6 in (150 mm) for a total of 18 in (450 mm). A further count was made of the

number of blows to advance an additional 2 in (50 mm). The Standard Penetration Test blow count or N-value was then taken as the sum of the penetrations

between 6 and 18 in (150 and 450 mm) as specified in JIS A 1219 and ASTM D1586

procedures.

The JIS sampler with its constant 1-3/8 in (35 mm) inside diameter was used

alternatively with the ASTM sampler with its 1-3/8 in (35 mm) inside diameter

shoe and 1-1/2 in (38 mm) inside diameter split barrel to evaluate the effect

of sampler shape on energy and SPT N-value results. The use of alternate

sampling in adjacent borings permitted the comparison of blow counts essen- tially at the same level with approximately the same energy. The effect of

sampler shape on blow counts could then be evaluated.

3.3 ENERGY MEASUREMENT PROCEDURES

The procedures used to measure the potential and kinetic energy of the hammer

and the energy passing through the drill rods have been documented in previous

reports (Kovacs et al., 1975, 1981, and 1983). They are briefly summarized

below for convenience.

Preparation

Fasten a target of black and white strips 1/8 in (3.2 mm) in width around the

hammer.

Insert the load cell in the drill rod and attach the anvil to the top of the

load cell

Connect the SPT Calibrator to the timer, oscilloscope, and tape recorder and

position the light beam scanners on the scanner holding rod and clamp it in

the testing position.

Perform the three-stage calibration of the Calibrator as prescribed by the

manufacturer' s instruction manual with the hammer at rest on top of the anvil.

Testing

Start the tape recorders and begin the Standard Penetration Test.

Read the parameter ER-j, the energy ratio to the nearest whole number, expressed

as a percentage of the SPT energy of 4,200 in-lbs (475 J); then after the blow,

read the peak force from the calibrator. During the test, the timer was read

and all of the information was recorded on a hand-held tape recorder for tabulation. Also, a multichannel tape recorder was used to record the scanner

11
output, the load cell output and the timer output for future analyses, as required. The oscilloscope displayed the shape of the stress wave after each

blow and the duration of the integration time. Reset the Calibrator for the

next blow.

3.4 DATA REDUCTION PROCEDURES

The average energy ratio, ERj, was evaluated in the field after each Standard

Penetration Test was completed. The energy ratio, ER-j and the integration

time that was recorded on the hand-held tape recorder were tabulated in the

field. The corrections Kj, K2 , and Kc which account for the fact that the

load cell is not positioned at the point of impact (K^), the drill rods are

not infinite in length (K 2 ) , and the actual compressive wave velocity in the

steel rods and couplings is different than the theoretical value built into

the Calibrator's energy ratio computation (K c ), were also computed. These

corrections have been discussed by Hall, (1982) and Kovacs et al . (1983).

Standard Penetration Test results are provided in section 5.

12
4. DRILLING AND TESTING SITES

4.1 INTRODUCTION

Standard Penetration Test data were obtained at Akita, Niigata, Tokyo, and

Yokohama, Japan. The locations are shown in figure 4 as sites A through L.

Sites were selected where liquefaction occurred and where liquefaction did not occur to obtain a variation in blow counts and soil conditions. Sites A through

C were chosen in the Akita area because of the May 26, 1983 earthquake. The

city-of Niigata (sites D through F) was chosen specifically for comparison with

the historical field SPT studies that were performed following the 1964 Niigata

earthquake. The Tokyo/Yokohama sites (G through L) were used to obtain more

information on Japanese operator characteristics and equipment under different

or additional soil conditions and thus obtain a better statistical sample of

the energy ratios and SPT practice for Japan.

4.2 AKITA SITES

Figure 5 illustrates the guide map of Akita showing sites A, B, and C in the

Hachiro-Gata area. In addition to sites A, B, and C, a fourth site known as Boring FD 7+415 was found during the course of testing in which a truncated

cone was tested using both cathead and rope and the Tombi methods. Seven

borings over the four sites yielded 958 data points in areas that liquefied

and those that did not liquefy during the May 26, 1983 earthquake. Figure 6

illustrates the bore hole testing arrangement at sites A, B, and C in which

six other types of in situ tests were performed.

4.3 NIIGATA SITES

Figure 7 shows a guide map of the Niigata area showing sites D, E, and F. Figure 8 illustrates the boring and testing arrangements for the three sites

at Niigata. Three sites were chosen in Niigata in which two of them had borings

in which the energy was monitored in the drill rods. These were sites D at

Kawagishi-cho and site F at the Showa-Ohashi bridge sites. Due to load cell

fatigue problems (4 out of 5 load cells failed), only a minimal amount of

testing was completed after sites D1 and D2 were evaluated. As a result, site

E testing was performed without energy measurements. Three borings in Niigata

resulted in a total of 638 data points. The same operator performed borings

D1 and FI while a second operator performed the investigations at borings D2

and El.

Figure 9 shows a detailed drawing of the Kawagishi-cho sites in which eight

apartment buildings exhibited significant movement during the 1964 earthquake.

Note that the present study location of borings D1 and D2 were adjacent to a previous study by Ishihara and Koga (1981). The close proximity of these two

studies will permit a comparison of blow counts obtained and an estimate of

the energy used in previous SPT studies at Niigata.

13
4.4 TOKYO SITES

A total of nine borings were conducted at six sites (G through L) in the Tokyo

area resulting in 618 data points (figure 10). In the Tokyo area, the J IS

sampler was driven using a donut- shaped hammer and the cathead and rope or the Tombi method of release.

14
Figure 4. SPT study region in Japan. Sites A through L (from 0Y0 Corp.)

15
Ohdate City

Kilometers

Figure 5. Guide map of the Akita area (from 0Y0 Corp.)

16
Akita Site B Hachiro-gata FD6 + 900

• Bore Hole (g) Vibrating Cone, Static @ Swedish Sounding

® Vibrating Cone, dynamic (D Dynamic Cone

© Dutch Cone © Ram Sounding (D Piezocone

Figure 6, Bore hole testing arrangement at the Akita sites (from 0Y0 Corp.)

17
Figure 7. Guide map of the Niigata area (from 0Y0 Corp.)

18
Niigata Site D Kawagishi Cho

©

D

Niigata Site E Showa Ohashi Left Bank

No. 1-1

E -1 • ©—©—© 0 0HU) ©

# No.1-2

0 1 2 3 4 5m

• Bore Hole (D Vibrating Cone, Static © Swedish Sounding

• Old Bore Hole © Vibrating Cone, dynamic © Dynamic Cone

© Dutch Cone © Ram Sounding © Piezocone

Figure 8. Bore hole testing arrangement at the Niigata sites (from 0Y0 Corp.)

19
(after Ishihara and Koga, 1981)

Figure 9. Detailed Map of the Kawagishi-cho site in Niigata (after

Ishihara and Koga, 1981)

20
21
5. SPT RESULTS

5.1 GENERAL

A total of 19 borings were made at 12 sites, and 78 individual Standard

Penetration Tests were performed using 19 different operators and conditions.

Of the 78 tests, 28 were performed using the ASTM sampler and the remaining 50 were performed using the J IS sampler. When the cathead and rope method was

used as the hammer release mechanism, the number of turns of rope around the

cathead varied as follows:

a. 14 tests -- 3/4 of a turn

b. 51 tests -- 1-3/4 turns

c. 8 tests -- 2-3/4 turns

These results are consistent with the recent survey by Yoshimi and Tokumatsu

(1983) in which a nominal two turns were used a majority of the time. Five

tests were also performed using the Tombi method.

Table 1 presents a tabulation of the results and test conditions for the 78

series performed in Japan. With the exception of the first two series (144

and 145 which were performed with a wooden guide pipe above the anvil) all

the tests were performed using a steel guide pipe during the performance of

the SPT. The Energy Ratio, N-value, boring number, nominal depth, the sampler

type, and number of turns used by the operators are listed in table 1. Further,

the dimensions of the cathead hammer and anvil used are summarized. Finally,

the rate at which the operators performed the Standard Penetration Tests in

blows per minute are given in the last column. To better appreciate the significance of these various test results, a graphical summary is presented and

discussed in the next section.

5.2 PRESENTATION OF ENERGY RATIO RESULTS, ERj (PERCENT)

A summary of the energy ratio data versus blow count for the operators using

cathead and rope or the Tombi method is presented in figure 11. Figure 11

demonstrates that the energy ratio is independent of blow count as found by

Schmertmann (1978) and Robertson et al . (1983). Comparing the range of energy

ratio values in Japan from figure 11 with those of the United States as given

by Kovacs et al . (1983), one finds that the Japanese data exhibits less scatter

than data from present U.S. engineering practice.

Figure 12, a frequency diagram of the data, indicates that the average is 68

percent with a standard deviation of 9.6 percent and a coefficient of variation

of about 14 percent. Data for U.S. practice averages approximately 55 percent

with a standard deviation of 12 percent and a coefficient variation of 22 percent. Figure 12 includes energy ratio results using the cathead and rope and

the Tombi methods. If the data for each of the release mechanisms are treated

separately the average for the Tombi method and for the cathead and rope method

would be 80 and 67 percent respectively. The ratio of the energy ratios for

the Tombi method and the cathead and rope method (80/67) equals 1.19 which

compares favorably with the ratio of 1.2 given by Tokimatsu and Yoshimi (1983).

22
To better appreciate how the energy ratio varies with operator, figure 13 has

been prepared in which the individual operators and their averages and sample

standard deviations (given in parentheses) are shown graphically with respect

to the average of all data. The small capital T beside five of the data points

represents the Tombi method was used.

Figure 14, illustrates the effect of the blow count and the number of rope

turns around the cathead during the performance of the SPT. The Tombi method

data have been excluded from figure 14. Figure 14 shows little effect of the

blow count as well as the number of turns of rope around the cathead. In

figure 15, ER i is plotted directly with the number of turns of rope used

around the cathead. The trend is contrary to what has been found in U.S.

practice where the energy ratio decreased with an increasing number of turns

especially after three turns were used around the cathead.

The difference in rope age is plotted on figure 16 for 1-3/4 turns of rope.

Figure 16 shows no appreciable difference in energy as a function of rope age.

Again, this is contrary to U.S. practice where older rope gives a lower energy

ratio. Two reasons may be cited as to why the number of turns of rope and

rope age did not have an effect on the average energy ratio in the drill rods.

First, a much smaller cathead diameter and rope diameter is used in Japan as compared to U.S. practice (Yoshimi and Tokimatsu (1983) and Table 1). Secondly, Japanese drill rig operators make a determined effort to throw the rope

off of the cathead during the down stroke. Thus, the number of turns of rope

recorded before each blow may not truly be the actual number of turns during

the fall of the hammer.

5.3 PRESENTATION OF ER j VERSUS DEPTH

5.3.1 Introduction

The figures in this section illustrate not only how N varies with depth because

of differences in soil layers but illustrates the energy variation within a given Standard Penetration Test profile with depth and the effects of the two

different types of samplers that were used.

5.3.2 Akita Sites

Figures 17a, b, and c illustrate the N-value profile with depth for borings A1

and A2, B1 and B2, and Cl and C2, respectively. In figure 17, the circled

data point was obtained using the JIS sampler while the triangular symbol is

used to designate the ASTM sampler data. The numbers in parentheses adjacent

to the data points are the average value of the energy ratio in the drill

stem, ER -j . A solid line connects the data points for a given boring. If one were to normalize the profile of N-value versus depth to a constant energy

ratio of 68 percent (N68 = N*ER-j/68) (based on figure 12) then the data

for each boring would be represented by the dashed lines on figures 17a, 17b,

and 17c.

23
5.3.3 Niigata Sites

In a similar manner, graphs have been prepared for the two sites in the

Niigata area. Figures 18a and 18b illustrate boring D1 and D2, respectively

for the Kawagishi-cho site. The symbols mentioned previously for figure 17 are also used in these and following graphs. Note that in boring D1 the energy

measurements did not take place until a nominal depth of 11 meters. Both

borings D1 and D2 were in a liquefied site. In figure 19 a similar profile of

N-value versus depth is shown based on a previous study by Ishihara and Koga

(1981). In figure 20, all three graphs (figures 18a and b and figure 19) have

been replotted without the data points for the raw data on figure 20. Fig- ure 20 shows reasonable agreement between the N-value profile with the exception

of depths between 15 and 18 meters.

In another part of the city on the left bank of the Showa bridge site, boring

El was completed to a depth of 20 meters without any energy evaluation, Fig- ure 21. Thus, it was not possible to normalize the N-value profile to an energy ratio of 68 percent. Note the low blow counts of approximately 10

blows per foot up to a depth of about 12 meters. Iwasaki et al., 1978, present

data shown in figure 22 from the Showa bridge site number 2 where liquefaction

occurred. The blow count profiles for figures 21 and 22 are similar to a depth of approximately 12 meters.

Across the river in a nonliquefied site, boring FI was drilled to a depth of

approximately 15 meters. Five Energy Ratio measurements were made thus permitting normalization of a portion of the N-value depth curve to a 68 percent

energy ratio. Figure 23 gives an example of the increase in blow count found

using the J I S sampler as compared to using the ASTM sampler. Figure 24 illustrates another N-value profile curve in a nonliquefied site at the Showa bridge

number 4 boring given by Iwasaki et al . , 1978. The blow counts between 2 and

4 meters are similar to those shown in figure 23 and increase with depth up to

12 meters.

5.3.4 Effect of Sampler Type on N-value

The Japanese and the Europeans have faithfully followed ASTM D 1586 since its

inception with regard to the physical dimensions of the SPT sampler. The

Japanese Industrial Standard A 1219 is based on the present (1984) version of

ASTM D 1586. In the United States, those in engineering practice utilizing

the SPT have declined to use the brass liner that is available from the manu- facturers in the United States for perhaps as long as 10 years. The probable

reason for not using a liner in the U.S. sampler with a 1-1/2 in (38 mm) inside

diameter barrel is the ease with which the soil sample can be examined and

removed from the sampler after each test. Even though the ASTM test method

calls for a uniform 1-3/8 in (35 mm) inside diameter split barrel it is now accepted practice in the U.S. to ignore this requirement and it appears that

only about 5 percent of the orders for SPT samplers request the liner (Acker

Drill Co. and Sprague & Henwood, Inc., 1984, private communication).

24
From the previous graphs in section 5.3, it is possible to compare the N-value

results at a given depth using a J I S sampler and an ASTM sampler to study the

effect of sampler type. Table 2 and figure 25 presents the results of this

comparison. The N-values have been normalized for a 68 percent energy ratio.

Three of the data points have been rejected in figure 25 because they involved

very abrupt changes in N-values. Thus, with the exception of one data point,

all of the remaining 14 data points lie below the one-to-one line indicating

that at the same depth, the JIS sampler resulted in greater N-values than the

ASTM sampler.

Schmertmann, in his review of this report, suggested that additional points

could be obtained comparing Ny$ with Nj by interpolating data on figures 17

through 19 and 21 and 23. When all the data points are plotted together,

figure 26 results. Figure 26 includes data where blow counts have been

normalized to 68 percent (50 points) as well as data points where energy ratios

have not been measured (29 points). The resulting equations from regression

analyses performed using data from figures 25 and 26 are given in table 3.

The question of which sampler shape factor relationship between Nys and Nj

to use may be answered by a review of table 3. The differences among the

six equations are minor from an engineering point of view. For simplicity,

we are recommending that the sampler shape relationship of Ny$ = 0*78 Nj

be used, which when rounded off is:

Nys = 0.8 Nj, for constant energy (5.1)

Note the blow counts are obtained at the same energy ratio.

*

25

Table 1

Tabulation

of

Results

and

Test

Conditions

Steel

Guide

Pipe

Unless

Mentioned

Rotary

Wash

w/MUD

and

Casing

Rate (

B/min) 

(19) o

CM

10.7 9’6

r-*. !c-.

m 15.6 8*91 13.7 11 11

Knocking

Head

H1

(in) (18) CO CO co CO co co co

2.5 2.5 2.5 2.5 3.

3.

85 (17) CO co CO co CO CO co CO CO co CO CO co

Hammer

Q

C (16) CM CM CM CM CM CM CM

1.75

in

t-* j

1.75

m

CM CM

OD (in) (15)

iTl

r-.

m 7.5 7.5 7.5 7.5 in

7.0 7.0 7.0 7.0

O'

s©

ON

v©

H (in)13.75 13.75 |13.75 13.75 13.75 |

13.75 13.75 13.75 13.75 13.75 13.75 16.0 16.0

Cathead

RPM (13) 167 167 55 55 55 55 1 176 v©

r-» 176 176 307 11

ID (in) (12) lO

mmmm

mm

m

mm

m in

m 8 5

(11) v© v© v© i© v© V© N©

6.5

m

v© |6.5

6.5 ' m

\D

6.5

sJ c

•H .

(10)

m

m

m

mmm

mm

m in

mmm

Operators 05 < < < < < < < w

ww

w fa fa

Remarks 00 |

Wood

guide

pipe,

new

3/A

in

rope

Wood

guide

pipe,

hold

drop

procedure

(HDP)

(HDP) (HDP) (HDP) ;

old,

3/4

In

rope |

Truncated

cone,

new

3/A

in

rope

Truncated

cone

Turns | |1 j3/4 |1

3/A \1

3/A |1

3/A 1

3/A 13/A |13/A 13/A 13/A 1 J3/A 13/A -3- CO T0MBI

u

Q)CLE

CO

vO <J < < < < *-) < —i

Depth (m) in CM CO

m vO c*. 00 20 - CM co <* 58

Boring |

B-2 1 CMA :

B-2

CMC

B-2 B-2

CMi

B-l B-l B-l [fd

7+A15

in

r^. e N (B/ft) |

CO -

CO CM CO Os CO 1

10 o o m O' CO

faW

w

CM 167 68 1 < ,0

_i

65

_ 00

v© 65 70 78 73 00 173 i

ao

Series 1 Q < m

'd- 1A6

c*.

'd- 00

<r 1A9 150 151 152 153 in

inm

<©m

26

a

indicates

ASTM

sampler

(without

liner)

Indicates

JIS

sampler.
Table 1

Tabulation

of

Results

and

Test

Conditions

Steel

Guide

Pipe

Unless

Mentioned

Rotary

Wash

w/MUD

and

Casing

0) 4J

CO OS

(B/min) (61) o

CM

10.7 9*6 11

r>.

15

15.6 00

V©

13.7 i j

Knocking

Head

a 'e 00 CO CO co CO co co co

2.5 2.5

m

CM

2.5 3

CO 3CO

0D

(in) (17) CO CO co co co co co CO CO co co CO CO

Hammer

Q 'c (91) CM CM CM CM CM CM CM

1.75 1.75 1.75 1.75 CM CM

OD (in) (15) 7.5

m 7.5 |

7.5 7.5 1

7.5 7.5 7.0 7.0 17.01

7.0 I

6,

7.9

6,

7.9

H (in) 3 13.75 13.75 13.75 13.75 13.75 13.75 13.75 13.75 13.75 13.75 13.75 j0*91 16.0

Cathead

RPM (£T) 167 167 55 55 55 55 iii

176 176 176 176 307 111

ID (in) (12)

mmm

mmmmmmmmmm

OD (in) (11) nO N© v© V© >© N© V©

6.5 |6.5 6.5

m

N©

—

6.5 |6.5

C

no,

m in

mmm

m

m

mmm

m

m

m

Operators < < < < < < < w

w Ed

w

Remarks 00

Wood

guide

pipe,

new

3/4

in

rope

Wood

guide

pipe,

hold [

drop

procedure

(HDP)

(HDP) |(HDP) (HDP);

old,

3/4

in

rope

Truncated

cone,

new

3/4

in

rope

Truncated

cone

Turns | 3

CO 3

co 3

co 1

3/4 1

3/4 13/4 |13/4 [13/4 13/4 13/4 13/4 1

3/4

TOMB I

Sampler -£> < *o < < —) < —> < < •n

Depth (m) CM co 15 V© r*«* 00 |02 3

CM CO 3 v©m 58

Boring | 3 B-2 B-2 B-2 B-2 B-2 J CMA B-2

l-fl i

-a 1

B-l \ «

FD

7+415

FD

7+415

N (B/ft) co - 3 CO CM CO Oh co o O o m O' 00

osW

w

CM 1

67 |68 64 70 65 68 65 70 CO 73 3

00 73 300

Series | - 3-3* 145 146 3

00

*3” 149 150 151 152 153 154 155 156

26b
Table 1

(Continued)

Rate

(B/mln) (19) 11 11 j 11 11 11 11 11 11 11 11 11 11 11

Knocking

Head

X c 00 2.5 in

CM

2.5

m

CM

2.5 in

CM

m

CM

in

CM

3.4 3.4 3.4 3.4 3.4

-S’ cn

Q

C

O

in

cn

3.5 3.5 3.5 3.5 3.5 3.5 3.5 cn cn cn cn cn cn

Hammer

Q

C (16)

2.25 2.25 2.25 2.25 2.25 2.25 2.25 2.25

0‘Z

2.0 2.0 2.0 2.0 2.0

OD (in) (15) in

CM 7.25 7.25 7.25 7.25 7.25 7.25 7.25

m

r-"-

m

m

r>.

m

m

m = 'c 13.0 13.0 13.0 13.0 13.0 13.0 13.0 13.0 I

CMcn

13.2 13.2 13.2 13.2 13.2

Cathead

RPM

(13) 304 Mfocn

304 280 280 280 280 280 i

vr> 161 11 iii178

ID (in) (12) 6.5 6.5 6.5 6.5 6.5 6.5 6.5 6.5

mmm

mm in

OD (in) (11)

m

N0

m

vD

in

sO

m

sD

6.5 in

vO

in

v£>

m

v£> 1

6.5 1 m

vO

m

\D

6.5

m

sO

m

vO

J cH (01)' 1 1 1 - 1 1 ' 1 m

mm

m inm

Operators O'

O

u o CJ o c_>O < < < < < <

Remarks 00

Old

1/2

in.

rope |

Rope

wet |

Rope

wet

Rope

wet |

Rope

wet [

Rope

wet

New

3/4

in.

wet

rope

New

3/4

in.

wet

rope

New

3/4

in.

wet

rope

(HDP);

rope

thrown

completely

off

cathead

Turns r-. 2

3/4 2

3/4 cn

CM 2

3/4 |23/4 |23/4 23/4 13/4 |1

3/4 113/4 1

3/4 13/4 cn 13/4

Sampler vO < < -) < >“5 < < —i < —) <

Depth (m)

m - CM

m 16 00 ON 20 J - CM 15 V0 00

Boring -3- C-2 C-2 j

C-2 C-2 C-2 C-2 C-2 C-2

C-l 1 CJ 1 o 1 O 1 U

C-l

N (B/ft) |

cn

00 37 |

33 <r |

30 30 16 J

24 j

25 33 35 26 CM

CM

W

W

CM

NO 70 1 72 1

69 68 <3 77 75 70 69 6, | £ 70

Series J - m 158 ^

O'in 160 161 162 163

'd- vO 165 166 167 168 691 170

26c
Table

1

(Continued)

|

-1 (

B/min)

(61)

!

1

1

1

1

1

1

1

1

1

1 CO

00

sO

00 21.5 15.7

j

111

1

T3

td

<D asw

c

i-4 *(JO£

H (in) 00 3.4 3.4 2.4 2.4 CN

2.4 2.4 12.4 2.5 1 2.5 2.5 ! CN CN CN

OD (in) (17) CO co ro CO CO CO CO CO CO

3.4 ! 3.4 ! CO CO CO

1Hammer

P C M i-|

(16) o

04 oCN

1

1

1

1 1

1

I

1

1

1

1 o

CN |

2.0 2.0

'

1

00 00 00

OD (in) (15) m 7.5 7.0 1

7.0 7.0 17.0 7.0 ov

in l7

' 5 7.5 7.6 1

7.6 i

7.6

X 'c

•H

13.2 13.2 |13.5 13.5 13.5 13.5 |

13.5 m

CO 13 l13 |13

11.0 11.0 11.0

Cathead

RPM 1

(13) 00 1

178 224 CN

CN |224 j

238

1

1

1

i

l1255 1l300 l 11

1

1

1

1

1

1

1

1

ID (in) (12) m m m m m m m m m m m

00

Nf

00

-3- 4.8

OD (in) |

(IT) 6.5 in

sO

l

1

1

1

l

1

l

l

l

l1

1

l

ll i sO sO sO

6.5 6.5

i

6.5

L (in) r

(10) in m l l i ' 1 1

5.8 5.8 5.8

Operators ON < < PQ « CQ CQ CQ CQ V CJ P P P

Remarks 00

Old

3/4

in.

rope

thrown

completely

off

cathead

Old

3/4

in.

rope

thrown

completely

off

cathead;

very

deliberate

Old

3/4

in.

rope

thrown

completely

off

cathead;

very

deliberate

(HDP) (HDP);

very

deliberate

(HDP);

very

deliberate;

old

1/2

in.

rope

(HDP);

new,

3/4

in.

(white)

rope

(HDP);

rope

thrown

off

cathead (HDP)

Turns r- 1

3/4 13/4 13/4 13/4 1

3/4 13/4 13/4

i

1

1

3/4 1

3/4 1

3/4 I

1

3/4 3/4 <rCO

3/4

Sampler sO < < < *-> < < < <3

Depth (m) m OS 20 -CN co Os OZ - 12 CO - 12

Boring C-l 1 o

CN

A

CN

AAA-2

A-l I-V A-l D-l D-l D-l

N (B/ft) CO 1

20 23 37 j

m NT m 59 29 sO 00 as

OS fr* W WCN 77 75 70 67 NT

r68 67 74 60 |99 |09 59 63 !

!

*3- sO

Series j

-

172 173 m sO

r*. 177 178 179 180 00

CN

00 183 00

26d
Table 1

(Continued)

Rate

(B/min) (19)

m 11

9.8

11.3 10.5 13.7 i 11 1 00O

CO

00 16.7 00m 13.5

Knocking

Head

X c

•H 00 CN (VI CN CN CN CN

2.8 00

CN

00

CN

00

CN

00

CN

2.8 2.8 2.8

OD (In) r-> co CO CO CO CO CO

3.2 1

CNCO

3.2 3.2 3.2 CNCO

3.2 3.2

Hammer

ID (in) (16) ao 00 00 CO 00 00

2.0 12.0 1

2.0 2.0 2.0

O

CN

2.0 o 'c O -H

(15)

v£>

r-»

n£>

rv. 7.6

v£>

r*. 7.6 7.6 7.5 1 m

m 7.5 1

7.5

m

7.5 in

X 'c C7I)

O

O o

11.0 o |

11.0 1

CN 12 12 12 CN CN CN 12

Cathead

RPM

(13) 1j 11 111 111 111 111 111 111 Iil 111 111 1 111 111

ID (in) (12) 00 00

nt

00

vr

00

vr

00

«d00

4.6 4.6 4.6 4.6

v£> NT

4.6 vO

'dsONT

OD (in) (11) in

s£>

m

sD

mso

6.5 6.5 6.5

v£> \D

-d4.6 1

sD

'O |

4.6 I4.6 4.6 4.6

J cH

L

(10) 5, 5.8 5.8 5.8 „

5.8 -

'd' *d- 'd' 'd' NT >dOperators Os Q Q Q Q Q Q

<0O e>

O o e> o o O

Remarks 00

(HDP) (HDP);

new,

wet

3/4

In.

(white)

rope

(HDP) (HDP);

old,

wet

5/8

in

rope;

flat

cathead |

(HDP) |(HDP) (HDP);

rope

thrown

off

cathead

Test

through

Kelly

(HDP)

Turns

Ni- ro

nT

CO

3/4 3/4 3/4 I

3/4 ||3/4 3/4 3/4 3/4

—

3/4 13/4 13/4 CO

Sampler |

v£> *-> < r> <2 *") < < *-) < *-) < < —)

Depth 1

(m)

mm sD 17.5 18 19 l

20 13 NT 15 16 fo. 00 Os 20

Boring |

-d- D-l D-l D-l 1

0-1 jD-l D-2 D-2 D-2 D-2

CNi D-2 D-2 D-2

N (B/ft) |

16 26 23 l

35 |

29 nt fv. Os 16 20 37 36 o

a* ^ Id w

CN 66 63 1 1

62 1 64 68 ' 1[

66 60 |I63 68 r-vO 71 09 in

Series ! -

185 186 187 J

00

00

Os

00 190 J191 192 193 194 195 196 197 198

26e

This

operator

normally

uses 1

3/4

turns

but

for

tests,

he

Is

using

3/4

turns.
Table

1

(Continued)

Rate

(B/min) (61)

13.9 17.8 0*61 |

23.5 |12.8 m v©

19.6 10.2 17.8 CM

18.9

i

i

1

1

Knocking

Head H (in) (18) 3

eg 3

eg

2.4

*!’Z 2.4 2.8 1

2.8 o

eg |

2.8 2.5 1

2.5 00

eg

00

CM

00

CM

OD (in) (17) o

eo

3.0 |3.0 3.0 3.0 3.5 3.5 CO

3.5 I3.0 13.0 o

CO

—

3.5

1

3.5

Hammer

q e M -T-i (91)

h©

1.6 1.6 1.6 I

vO 00

2.0 1

1.9 Oh 00 00 00 00

1.8

OD (in) (15)

00

7.8 00

e7.8 7.8 J

0*8 7.6

00

Ohm

00 o00 o00

1

« (in) (14) 10.4 10.4 10.4 10.4 3

o

inO

13.0 v©

JCh©CO 13.6 13.6

1 1

8'6

10.6

1

10.6

Cathead

RPM

(13)

1

1

1

1 1 1

J

i

i

l

1

1

1 Very

Slow

1

1

1

1

1

1

1

1

1

1

1

1

i

1

1

1

ID (in) eg

h© hO hO hO v©

4.6 m4.6 in

>3- 4.5 4.5 4.3 003

4.8

OD (in) (id Oh Oh Oh

r^.

Oh Oh

e4.6 \0

h©3

1

0*9 h© h©

4.3 inv©6.5

c

•H L

do)

ro3co3co3

co3co3 m m m m m CO n© V©

Operators

|

Oh o Q Q Q Q sc M Sd *-) J S E

Remarks 00

(HDP);

rigid

hook

on

hammer;

new

white

-

J-°Pe

Test

through

Kelly

fai

Outside

Kelly

Old,

3/4

in.

rope;

outside

Kelly

(HDP);

very

deliberate;

old,

5/8

in.

rope;

outside

Kelly

Truncated

cone;

old,

5/8

in.

rope;

outside

Kelly

(HDP);

Old,

5/8

in.

rope;

outside

Kelly

New,

3/4

in.

rope;

outside

Kelly

New,

3/4

in.

rope;

outside

Kelly

Old,

1/2

in.

rope;

outside

Kelly;

usually

inside |

New,

1/2

in.

nylon

rope;

outside

Kelly

(HDP);

old,

1/2

in.

Manila

rope

Turns e- 1

3/4 13/4 l

1

3/4 13/4 1

3/4 3

CO 3\CO

CM

3

CO 1

3/4 3

CO TOMBI 1

3/4 1

3/4 j

1

3/4

Sampler h© *~3 < < *-) *->

Depth (m) m - eg co 3 m V©

CM

vO 27 m 13.5 3-

35 m h©

Boring 3 1 fa

F-l i fa

I fa

F-l G-l

G-2 i G-3 G-4 G-4 ± M M

N (B/ft) co 1

58 25 25 25 Oh o 69 52 Oh 40 1

1 eg m 20

•H'-'v &

fa V-' eg I

42 63 v© 50 M v©

oo

CO

CO 77 50 68 86 |

92 80

Series Q

Oh

O' |003 201 202 203 204 J205 206 207 00oeg209 210 211 212

26f

Cathead

rope

attached

to

one

side

of

hammer
Table

1

(Continued)

O 4J O 0) 04 Cd

• (X,

- CU Z >-/

8

- co 5 XL

o. e

26g

Table 2. Summary of Direct Measurement Data

Comparing Nys and Nj

Boring

No.

(1)

Blow Counts in

Blows/Foot

Depth

(m)

(2)

N US

(meas.

(3)

Nj

(meas.

(4)

Fig Ref.

(5)

A 1,2 11 38.2 57.2 17a

A 1,2* 12 28.2 14.6 17a

A 1,2 13 4*. 5 5.5 17a

C 1,2 11 16.1 25.5 17c

C 1,2 12 33.5 38.0 17c

C 1,2 15 34.5 38.0 17c

C 1,2 16 27.0 44.5 17c

C 1,2* 17 30.0 18.0 17c

C 1,2 18 22.6 32.5 17c

C 1,2 19 18.3 22.6 17c

C 1,2 20 25.5 26.5 17c

D 1,2 14 8.5 15.8 18a,

D 1,2 15 19.0 16.5 18a,

D 1,2 16 14.8 15.8 18a,

D 1,2 17 20.9 23.7 18a,

D 1,2 18 21.6 33.2 18a,

D 1,2 19 31.8 35.0 18a,

D 1,2* 20 28.1 9.6 18a,

Notes: 1) Direct measurement blow counts were

normalized to average energy ratio of

68 percent.

2) Asterisk indicates data was not used

because of abrupt changes in N Values

27
Table 3. Summary of Regression Analyses

Condition Equation

Data in figure 25 NjS

- 0.78 Nj

NUS = 2.67 + 0.70 Nj

NUS = 1.36 Nj 0 ’ 84

Data in figure 26 NUS = 0.79 Nj

Njs = 3.27 + 0.67 Nj

% = i- 83 nj

0,75

Note: The residual standard deviations for the

above equations are approximately four.

28
100

80

Series 144-221

Includes 3/4, 1-3/4, & 2-3/4 turns

All data

O OT

©

b o

O

<8

o

oS

BT

CD

O Cb

60

QC

LU

40 —

20 —

°A A

A

B

©

8 — r7 & V

V

*

V

V — O A • G © M

V

A B A H a N

C 1 0

v D J © P _ O E K T beside symbol indicates

O F # L

Tombi method performed

i i i i

by operator

. 1 . i ,

i 10 20 30 40 50 6(

N - BLOWS PER FOOT

69

Figure 11. Summary of ER-j data vs N-value by operator

29
20

18

16

14

12

10

8

6

4

2

0

58.8 68.3 77.8

All Data

Avg - 68.3%

o - 9.6%

CV - 13.8%

40 50 60 70 80

ERj - (%)

i 90

Figure 12. Frequency diagram of ER-j results

30
OPERATOR

ERj

AVG.

B

C

20 40

69.5

(a =3.7)

70.0

(3.3)

68.8

( 6 . 0 )

60.3

(7.2)

ERj (%)

60 80

OO

% 4

0$&>

ODD

I So 8

imc®?

100

-1-3/4

-2-3/4

3/4 T

T

T

E 73.8

(3.3)

F

G 64.9

(4.1)

00 o o

Truncated

cone

Tombi (T)

1-3/4

3/4 T

T

H 81.5

(6.4)

I 33.0 O

J 50.0

K 68.0

O ^ Average of all data

O Ot

L 92.0 0

M 75.3

(4.5)

30 0 0

N 78.0

(5.7)

0 00

T 0 59.5

(3.5)

0 0 OT

P 68.0 (5

Tombi Method

(from above)

1

80.4

(6.7)

1 1

d o<mo

i 20 40 60 80 100

Figure 13. Energy ratio variation by operator

31
ER

j

(%)

100

80

60

A

I— A

^ AA

hA /w A

O

A o

A 2

l A © a

^b°

o

0^

A

A

A

AA

°Sp

All data

A

A

A ^

§0° A

A

A

A A

40

20

No. of

turns

o 3/4

A 1-3/4

2-3/4

0 10 20 30

A

069

40 50 60

N - BLOWS PER FOOT

Figure 14. ER -j vs N-value showing effects of number of turns of rope

around the cathead

32
40

o

o

Tombi 3/4 1-3/4 2-3/4

NUMBER OF ROPE TURNS

AROUND CATHEAD

3-3/4

Figure 15. ER-j vs number of rope turns around the cathead

33
ERj

(%)

100

80

60

40

A

A

A

A ^

A 2*6 A A A

A AA A

^

A a

a A A

A*

A A A A

A i

A

A* A

A*

A A*

1-3/4 turns of rope (old & new)

20

A Old rope

New rope

* Rigid hook on hammer

2 numeral indicates two data points

± -L 10 20 30 40

N - BLOWS PER FOOT

50 60

Figure 16. ER-j vs N showing the effect of rope age using 1-3/4 turns of

rope around the cathead

34
0

2

4

6

8

10

12

14

16

18

20

N-BLOVVS PER FOOT

10 20 30 40 50

—r 1 1 t rAkita Site A

Data from borings A-1

and A-2

O JIS sampler

A ASTM sampler

0 ERj - %

N 68

. N-value vs depth profile for the Akita area: borings A-1

and A-2

35
0

2

4

6

8

10

12

14

16

18<

20

17b

N-BLOWS PER FOOT

10 20 30 40 50

Akita Site B

Data from borings B-1

and B-2

O JIS sampler

A ASTM sampler

() ERi -%

Bor B-2

N-value vs depth profile for Akita area:

and B-2

borings B-1

36
0

2

4

6

8

IP

12

14

16

18

20

N-BLOWS PER FOOT

10 20 30 40 50 —i

i

1 1 rAkita Site C

Data from borings C-1

and C-2

O JIS sampler

A ASTM sampler

( ) ERj-%

(61) (70)

N-value vs depth profile for Akita area:

and C-2

borings C-1

37
DEPTH

(meters)

N-BLOWS PER FOOT

Figure 18a. N-value vs depth profiles for the Niigata areas: boring D-l

38
0

2

4

6

8

10

12

14

16

18

20

NN-BLCVVS PER FOOT

10 20 30 40 50

i

i i i i

Kawagishi-cho Site

Boring D-2

O JIS sampler

A ASTM sampler

( ) ERj - %

n68

alue vs depth profiles for the Niigata areas: boring D-2,

agishi-cho site

39
DEPTH

(meters)

N-BLOWS PER FOOT

Figure 19. N-value vs depth profile for the Kawagishi-cho site in

Niigata (after Ishihara and Koga, 1981)

40
0

2

4

6

8

10

12

14

16

18

20

. r

N-BLOWS PER FOOT

10 20 30 40 50

I I

1 1 T"

value (uncorrected for Energy Ratio) vs depth compiled

'•om figures 18a, 18b, and 19

41
0

2

4

6

8

10

12

14

16

18

20

N-BLOWS PER FOOT

10 20 30 40 50

i t —T"i rvs depth for boring E-l, the left bank of the Showa

ite, liquefied site

42
0

2

4

6

8

10

12

14

16

18

20

NN-BLOWS PER FOOT

20 30 40

r 1— r

Showa Bridge No. 2

Niigata City

ralue vs depth for Showa bridge no.

: ter Iwasaki et al . , 1978)

50

—r~

1978)

, liquefied site

43
0

2

4

6

8

10

12

14

16

18

20

23

i

N-BLOWS PER FOOT

10 20 30 40 50

I I “I "V"

Showa Bridge Site

Boring F-1

O JIS sampler

A ASTM sampler

( ) ERj - % —im 68

(42)

r(53)

N-value vs depth for boring F-1, the Right Bank of the

Showa bridge, a non-liquefied site

44
0

2

4

6

8

10

12

14

16

18

N-BLOWS PER FOOT

10 20 30 40 50

“i 1 1 1 r- Showa Bridge No. 4

. N-value vs depth for Showa bridge no. 4, a non-1 i quef i ed

site (after Iwasaki et al., 1978)

45
BLOWS

PER

FOOT

i

Figure 25. N-value correlation between JIS and ASTM samplers,

normalized to average Energy Ratio of 68 percent,

direct measurement data

46
Nj -BLOWS PER FOOT

Figure 26. N-value correlation between JIS and ASTM samplers,

direct measurement data and data obtained from

i nterpol ati on

47
6. APPLICATION

6.1 COMPARISON OF JAPANESE ERj and UNITED STATES ERj

It appears that the average value of energy ratio in Japan is approximately 68

percent of the available free-fall energy. This observation is based on field

tests at three locations and comparison of blow counts obtained up to 20 years

ago in the Niigata area where the soil profiles appear to be similar. This

value compares with approximately 55 percent energy ratio for U.S. data published by Kovacs et al . , (1983). It must be recognized that the U.S. data for

safety hammers varies between approximately 40 and 75 percent while the data

for donut type hammers varies from 30 to about 55 percent with two data points

at approximately 70 percent. Thus, the scatter of U.S. data is extremely

broad compared to the more narrow spread of data from Japan, as summarized in

table 1 and shown in figure 12.

6.2 EVALUATION OF THE RATIO OF Nns/N.i TAKING INTO ACCOUNT ENERGY RATIO AND THE

SAMPLER SHAPE FACTOR

According to Schmertmann, (1975) and Schmertmann and Palacios (1979), the

N-value is inversely proportional to the energy used to drive the sampler.

Thus we could approximate the blow count under condition 2 knowing the blow

count and energy for condition 1 and the energy for condition 2 by means of

eq. (6.1).

Ni E i = N2

E 2 (6.1)

Such relationships have also been shown by Kovacs et al. (1983). We can now expand eq. (6.1) by including a sampler shape factor and performing an experiment as we have done in Japan. For example,

(N-E-S)us •= (N-E-S)j (6.2)

where the subscript, US, indicates the blow count and energy ratio obtained

using the ASTM sampler, the subscript, J, indicates the blow count and the

energy ratio obtained using the JIS sampler, and S is the sampler shape factor

required to balance the equation. In this particular case, the energy ratio

on both sides of the equation can be equal to 68 percent, the average energy

obtained in Japan. Using eq. 5.1, we can obtain a relationship between the

blow counts at the same energy between the ASTM sampler and the JIS sampler.

It is now possible to compute the ratio of Nys to Nj for the cathead and rope

method used in both countries based on an average energy ratio and effects of

sampler geometry. Substituting the values of average energy ratio into equation 6.2 and assuming Sj equals unity, we find that the ratio of Ny$

to Ncj equals 0.98 or approximately unity.

NUS _ ER

J S

j _ 67.4 x 1.0 . N cj ER US S US 55 x !* 25

(6.3)

48
It should be remembered that the range of U.S. energy ratio is quite large and

as a result, the results of equation 6.3 will vary from approximately 1.80

when a 30 percent energy ratio is used to a low value of 0.72 when 75 percent

energy ratio is used.

Applying the same principles, and solving for the relationship between Nys and

Ntj for the data obtained using the Tombi method we find the values after

inserting them into equation 6.2 as shown in equation 6.4. The corresponding

value is 1.17 and not the value of 1.4 as suggested by Tokumatsu and Yoshimi

(1983). Note Tokumatsu and Yoshimi (1983) have not introduced the factor of

the differences in internal shape between the ASTM and J IS sampler.

N

US . ERJ

s

,i 80.4 x 1.0 , . Ncj

‘ ERUS S US

' 55 X 1.25

" L ' U

^

Again, the value obtained in eq. (6.4) will vary depending upon the actual

value of U.S. energy ratio used. For example, the ratio is 2.15 if the U.S.

energy ratio is 30 percent, while a ratio of 0.86 is obtained when a value of

75 percent for the U.S. energy ratio is used. Therefore, we can conclude that

the ratio of Ny$/Nj will vary as shown in table 4, assuming that the blow

count rate difference between the U.S. and Japan (US 0 30 to 60 blows per

minute and Japan @ 7 to 25 blows per minute) does not influence the ratio.

The aspect of blow count rate difference must be addressed before final ratios

can be estimated. The use of bottom discharge drill bits used by the Japanese

is another factor which is not considered in the U.S. /Japanese blow count

ratio. Schmertmann (private communication, 1984) relates a case "where the

use of bottom discharge bits in a sand reduced blow counts by an average

factor of 2.06." Parsons (1966) gives field blow count evidence where the

average N-value in auger borings made with drilling mud (drilling mud was

used in this study) was about 2.5 times those in cased borings with water

used as the drilling fluid.

6.3 EVALUATION OF JAPANESE DATA BASE AND EFFECT ON PRESENT ENGINEERING

DESIGN CURVES FOR LIQUEFACTION POTENTIAL

Based upon the discussion and data presented in sections 5 and 6 of this report,

it appears that the blow count ratio between U.S. and Japan engineering practice

is, on the average , approximately equal to unit/ when considering only energy

and sampler effects, and not considering rate and bottom discharge. At this

time, finer resolution of the data is not possible because of the wide variability in the conditions used for the Standard Penetration Test and the wide

variability in the energy measurement data.

49
Table 4. Summary of Blow Count Ratios, Ny$/Nj

for Different Assumed Energy Ratio

Conditions

Release

Mechanism

U.S.

ERi

(%)

JAPAN

ERi

(%)

N US

N cj

N US

Ntj

Cathead and Rope 30 67.4 1.80

Cathead and Rope 75 67.4 0.72

Cathead and Rope 55 67.4 0.98

Tombi Method 30 80.4 2.15

Tombi Method 75 80.4 0.86

Tombi Method 55 80.4 1.17

50
7. FINDINGS

Based on this investigation, it was found that:

1. The (1983) equipment and procedures used to perform the Standard

Penetration Test in Japan differ from the 1983 engineering practice in

the United States. These variations result in differences in the average

energy passing through the drill rods, ER-j . When the cathead and rope

method is used in Japan as the hammer release mechanism, ERi averages

approximately 67 percent. When the Tombi method (free-fall) is used, ER-j

averages approximately 80 percent. These values compare with an average

of approximately 55 percent for published U.S. data from cathead and rope

Standard Penetration Tests.

2. It was observed that the bore hole drilling mud level was not maintained

when the drill rods were withdrawn. This practice and the use of bottom

discharge bits could result in lower blow counts when compared to blow

counts obtained using U.S. engineering practice.

3. There is less scatter in the Japanese energy data than the U.S. energy

data.

4. The energy ratios for the Tombi method is approximately 1.19 times the

average energy delivered in the Japanese cathead and rope method. This

ratio compares favorably with the ratio of 1.2 given by Tokimatsu and

Yoshimi (1983).

5. The number of turns of rope around the cathead and rope age had relatively

little effect on ER-j in Japan in contrast to U.S. experience.

6. The effect of sampler type on the standard penetration resistance, N, is

significant. On the average, standard penetration resistance values obtained

using an ASTM sampler were found to be approximately 20 percent lower

than penetration resistance values obtained using the Japanese JIS sampler

at the same energy ratio.

7. The ratio of Nys/Nj varies as shown in table 4, section 6.2. However,

on the average, the ratio computes to be 0.98 when the cathead and rope

method is used as the hammer release mechanism. When the Tombi method is

used to obtain the Japanese N-vaTue, the ratio is 1.17. These average

ratios consider energy and sampler, but not rate and bottom discharge

effects, nor other important effects possibly not identified in this

study.

51
8. CONCLUSIONS

The design curves to evaluate liquefaction potential should be used with caution

because of the variability in the ratio of U.S. blow counts to Japanese blow

counts, Nys/Nj. For the cathead and rope method as the hammer release mechanism,

and considering only energy and sampler effects, the ratio of Nys/Nj varied

from 0.72 to 1.80. When the Tombi method was used, the ratio of Nys/Nj

varied from 0.86 to 2.15. Because of this variability, it would be prudent to

reexamine the design curves used to evaluate liquefaction potential considering

this variation. It may also be necessary to reference the design curves to a specific energy. A suggested approach to energy normalization has been given

by Kovacs et al (1984).

52
9. ACKNOWLEDGMENTS

This cooperative study was supported in part by project-related engineering

and scientific study funds of the Bureau of Reclamation, U.S. Department of

the Interior, the Naval Facilities Engineering Command and the Waterways

Experiment Station. The field data acquisition was managed by the National

Bureau of Standards while the National Bureau of Standards and the Bureau of

Reclamation also provided engineering manpower. E. D. Anderson of NBS and

J. A. Farrar of the Bureau of Reclamation provided assistance to William Kovacs

during the field program. The 0Y0 Corporation of Tokyo and the Public Works

Research Institute of the Ministry of Construction of the Japanese acted as hosts. The 0Y0 Corporation provided logistical support for data acquisition

that included transportation of field equipment and personnel, drilling of

bore holes, and performing the necessary field tests.

The regression analysis for table 2 was performed by S. Leigh and F. Y. Yokel.

The figures were prepared by R. Mele and K. Mackley.

The manuscript was critically reviewed by N. J. Carino, J. H. Schmertmann, and

F. Y. Yokel. The assistance of the abovementioned organizations and individuals

is greatly appreciated.

53
10 . REFERENCES

1. Hall, J. R. (1982), "Drill Rod Energy As A Basis for Correlation of SPT

Data," Proceedings of the Second European Symposium on Penetration Testing,

Amsterdam, A. A. Balkema, Rotterdam, Vol . 1, pp. 57-60.

2. Hvorslev, M. J. (1949), Subsurface Exploration and Sampling of Soils for

Civil Engineering Purposes , U.S. Army Engineer Waterways Experiment

Station, Vicksburg, Mississippi, 521 pp; reprinted by the Engineering

Foundation, 1962.

3. Ishihara, K. and Koga Y. (1981), "Case Studies of Liquefaction in the

1964 Niigata Earthquake," Soils and Foundations , Japanese Society of

Soil Mechanics and Foundation Engineers, Vol. 21, No. 3, pp. 35-52.

4. Iwasaki , T., Tatsuoka, F., Tokida, K., and Yasudu, S. (1978), "A

Practical Method for Assessing Soil Liquefaction Potential Based on Case

Studies at Various Sites in Japan," Proceedings of the Second International

Conference on Microzonation for Safer Construction Research and Application, Vol. II, pp. 885-896.

5. Kovacs, W. D., Evans, J. C., and Griffith, A. H. (1975), "A Comparative

Investigation of the Mobile Drilling Company's Safe-T-Dri ver with the

Standard Cathead with Manila Rope for the Performance of the Standard

Penetration Test," Purdue University Report dated July, 1975, 127 pp.

and Appendices.

6. Kovacs, W. D. , Salomone, L. A., and Yokel, F. Y. (1981), "Energy

Measurement in the Standard Penetration Test," Building Science Series

135 , Natonal Bureau of Standards, U.S. Government Printing Office,

Washington, D.C., 99 pp.

7. Kovacs, W. D., Salomone, L. A., and Yokel, F. Y. (1983), "Comparison

of Energy Measurements in the Standard Penetration Test Using the Cathead

and Rope Method," Final Report , prepared for the U.S. Nuclear Regulatory

Commission, NUREG/CR 3546, 92 pp.

8. Kovacs, W. D., Yokel, F. Y., Salomone, L. A., and Holtz, R. D., (1984),

"Liquefaction Potential and the International SPT," Proceedings of the

8th World Conference on Earthquake Engineering, San Francisco, CA,

July 1984, in press.

9. Parsons, J. D. (1966), "A Discussion of "Standard Penetration Tests:

Its uses and Abuses," by G. F. A. Fletcher, Journal of the Soil Mechanics

and Foundations Division , ASCE, Vol. 92, No. SM3, pp. 103-105.

10.

Robertson, P. K., Campanella, R. G., and Wightman, A. (1983), "SPT-CPT

Correlations," Journal of the Geotechnical Engineering Division , ASCE,

Vol. 109, No. 11, November, pp. 1449-1459.

54
11. Schmertmann, J. H. (1975), "Measurement of In Situ Shear Strength,"

State-of-the-Art Presentation to Session 3, ASCE Specialty Conference on

In Situ Measurement of Soil Properties, North Carolina State University,

Raleigh, North Carolina, June 1975, pp. 57-138.

12. Schmertmann, J. H. (1978), "Use of SPT to Measure Dynamic Soil Properties? - Yes But ....!" Special Technical Publication 654 , American Society for

Testing and Materials, Symposium on Dynamic Field and Laboratory Testing

of Soil and Rock.

13. Schmertmann, J. H. (1979), "Statics of SPT," Journal of the Geotechnical

Engineering Division , ASCE, Vol. 105, No. GT5, pp. 655-670.

14. Schmertmann, J. H. (1980), "Guidelines for Cone Penetration Test - Performance and Design," Report, FHWA-TS-78-209 , Federal Highway

Administration Implementation Division, 145 pp.

15. Schmertmann, J. H. and Palacios, A. (1979), "Energy Dynamics of the SPT,"

Journal of the Geotechnical Engineering Division, ASCE, Vol. 105, No. GT8,

pp. 909-926.

16. Seed, H. B., Idriss, I. M. , and Arango, I. (1983), "Evaluation of

Liquefaction Potential Using Field Performance Data," Journal of

Geotechnical Engineering , ASCE, Vol. 109, No. 3, pp. 458-482.

17. Tokimatsu, K. and Yoshimi, Y. (1983), "Empirical Correlation of Soil

Liquefaction Based on SPT N-Value and Fines Content," Soils and

Foundations, Japanese Society of Soil Mechanics and Foundation Engineering,

Vol. 23, No. 4, pp. 56-74.

18. U.S. Department of the Interior, Bureau of Reclamation (1974), Earth

Manual , U.S. Government Printing Office, Washington, D.C., 810 pp.

19. Yoshimi, Y. and Tokimatsu, K. (1983), "SPT Practice Survey and Comparative

Tests," Soils and Foundations , Japanese Society of Soil Mechanics and

Foundation Engineerings, Vol. 23, No. 3.

55
NBS-114A (REV. 2 -80 ) U.S. DEPT. OF COMM. 1. PUBLICATION OR 2. Performing Organ. Report No. 3. Publication Date BIBLIOGRAPHIC DATA

SHEET (See instructions)

REPORT NO.

NBSIR ' 84-2910 August 1984

4. TITLE AND SUBTITLE

Field Evaluation of SPT Energy, Equipment, and Methods in Japan Compared with

the SPT in the United States

5. AUTHOR(S)

William D. Kovacs ; Lawrence A. SAlomone

6. PERFORMING ORGANIZATION (If joint or other than NBS, see instructions)

national bureau of standards

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

7. Contract/Grant No.

8. Type of Report & Period Covered

9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City. State, ZIP)

10. SUPPLEMENTARY NOTES

| | Document describes a computer program; SF-185, FIPS Software Summary, is attached.

11. ABSTRACT (A 200-word or less factual summary of most significant information,

bibliography or literature survey, mention it here)

If document includes a significant

Field energy measurements on Japanese drill rigs were made during the performance

of the Standard Penetration Test to document the difference between Japanese and

present U.S. Practice. A total of 78 Standard Penetration Tests were performed

using 19 different testing conditions (equipment and operators). Over 2000 data

points are reported.

Results from this investigation show that the average value for ER^ (the ratio

of the energy passing through the drill rod to the theoretical free-fall energy)

using Japanese equipment and operators is 68 percent with a standard deviation of

9.6 percent .Considering only energy and sampler effects, the ratio of U.S. blow

counts to Japanese blow counts (N^/Nj) is 0.98 (variation between 0.72 and 1.80)

when the cathead and rope method was used as the hammer release mechanism and

using ER equals 55 percent and ER equals to 67.4 percent. When the Tombi

method (free-fall) was used, the ratio of N /N is 1.17 (variation between 0.86

and 2.15) when ER equals 55 percent and ER^ equals 80.4 percent. It was found

that the Japanese use bottom discharge drill bits and an SPT sampler with a con- stant inside diameter of 1-3/8 in (35 mm) in contrast to U.S. procedures and

equipment. A shape factor to account for differences in sampler is presented.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolons)

Energy measurement; field testing; in situ testing; liquefaction potential;

soil mechanics; SPT; Standard Penetration Test.

13. AVAILABILITY

[^3 Uni imited Q31 For Official Distribution. Do Not Release to NTIS

Order From Superintendent of Documents, U.S. Government Printing Office, Washington, D.C.

20402.

[XJ Order From National Technical Information Service (NTIS), Springfield, VA. 22161

14. NO. OF

PRINTED PAGES

72

15. Price

$ 10.00

I

U SCOMM'DC 6043-P80
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