Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

Pull-out Experiments of Flip-Type End Anchors Buried or Pushed in Model
Ground of Dry Sand
Shota YOSHIDA
Civil engineer, Daisho Corporation, Nagahama, Shiga, Japan

Masanori KANNOEngineer, Hokuriku Regional Development Bureau, Ministry of Land, Infrastructure, Transport and Tourism, Japan

Tatsunori MATSUMOTO
Professor, Graduate School of Kanazawa University, Kanazawa, Japan
Email: matsumoto@se.kanazawa-u.ac.jp

Shinya SHIMONOTechnician, Kanazawa University, Kanazawa, Japan

Takayoshi YOSHIDA
Civil engineer, Daisho Corporation, Nagahama, Shiga, Japan

Shun-ichi KOBAYASHI
Associate Professor, Graduate School of Kanazawa University, Kanazawa, Japan

ABSTRACTEnd-resistance type earth anchors are often employed to reinforce slopes or to ensure slope stability. Hulk Earth anchor
developed by Anchoring Rope and Rigging Pty Ltd (AR+R) in Australia is one of flip-type end earth anchors (hereafter,
flip anchor). The flip anchor is installed in the ground by driving or press-in. When the flip anchor is installed in the
ground, the end plate is closed to facilitate the penetration process. When pull-out force is applied to the anchor throughpulling rod or wire, it is expected that the end plate is opened with increasing the pull-out displacement to enhance thepull-out resistance. At present, pull-out resistance mechanism of the flip anchors has not been fully understood. Hence,in this research, fundamental push-in and pull-out experiments were carried out to investigate performance of the flip
anchors in dry sand model ground. Furthermore, push-up experiments of a trap door in a dry sand model groundsimulating an anchor were carried out to investigate the mechanism of the resistance of the anchor in plane strain
condition. An image analysis of the ground deformation was conducted in this series of the experiments. A simple
model of the ground failure was used to obtain theoretical values of the pull-out resistance of the anchor.
Key words: End-anchor, Pull-out resistance, Dry sand, Jack-in installation, Buried installation

1. Introduction

developed in Australia (Anchoring Rope and Rigging Pty

1. 1. Background
Heavy rains and/or strong winds often cause slope

Ltd, 2018).

failures, and collapses of towers and vinyl houses (plastic

1. 2. Flip-type earth anchor

greenhouses).

The flip anchor is known as a kind of end-anchors
which is used to reinforce slopes or support towers or
pipe lines. The anchor is driven or pressed into theground by using a driving rod with its head closed (Fig.
1a). After the completion of the anchor installation, theOne of emergency and prompt counter measuresagainst these damages is the use of end-anchors that canbe installed in the ground by press-in or driving. A flip
type end anchor, called Hulk earth anchor, has been

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Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

driving rod is removed and the anchor is pulled withpulling rod or pulling wire. It is expected that the anchor
head will be opened during the pulling process, as shownin Fig. 1b, to enhance the pull-out resistance.

2.1. Model ground
The model ground was prepared in the rigid
rectangular soil box with a height of 530 mm, a length of
800 mm and a width of 500 mm (Fig. 2). Dry silica sand#6 was used for the model ground. Physical properties of

Pull-out

Tail(a) Installation process
Fig. 1

Rod or wirefor pullingthe sand are listed in Table 1.

Head(b) Pull-out process

Example of flip anchor

1.3. Objectives and contents of the research
A design method for the flip type anchor has not

Fig. 2

fully been established. Hence, an objective in thisresearch is to investigate fundamental pull-out resistance

Table 1.

Soil box

Physical properties of dry silica #6

Density of soil particle, s (g/cm3)

2.67

Maximum dry density, dmax(g/cm3)

1.604

Minimum dry density, dmin (g/cm3)

1.268

Furthermore, push-up experiments of a trap door

Maximum void ratio, emax

1.089

simulating an anchor were carried out, in order to

Minimum void ratio, emin

0.652

investigate mechanisms of the pull-out resistance ofCohesion at peak strength, cp' (kN/m2)

10.3

anchors in more simplified experimental conditions

Int. friction angle at peak strength, p' (deg)38.6(plane strain conditions). A theoretical consideration is

Cohesion at residual strength, cr' (kN/m2)

4.6

made for the experimental results.

Int. friction angle at residual strength, r' (deg)34.8

mechanisms of the anchor through a series of push-in andpull-out experiments, and pull-out experiments of theanchors in dry sand model ground.

2. Outline of experiments

The model ground was prepared with 10 soil layers

Two types of experiments were carried out in thispaper.

of 50 mm thick and one layer of 30 mm thick. The sandwas put into the soil box for each layer, and the sandAnchors were pressed into the model ground tolayer was compacted to get a designated density (relative

different depths, and then they were pulled out. This typeof experiment is called “press-in and pull-out experimentdensity Dr = 82%, dry density d = 1.533 g/cm3). This
procedure was repeated to complete the model ground of(PI & PO test)”. In another type of experiment, anchors

530 mm high.

were embedded in the model ground during its
preparation, and a pull-out experiment (PO test) was
carried out. The same model ground and anchors were

2.2. Anchors used
Three types of flip anchors were used in theused in these experiments.

experiments. The dimensions of the anchors are indicatedin Fig. 3. They are named S-, M- and L-anchors,according to the project area, A.

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Proceedings of the First International Conference on Press-in Engineering 2018, Kochi(mm)

S-anchor

Push-inF

P

Pull-out
Pulling
wire or rod

G.L.

Pulling
wire or rod

Drivingrodzt1

A = 18.42 cm 2
M-anchor

Fig. 4Illustration of push-in and pull-out experiment2

A = 69.32 cm
L-anchor

Fig. 5 Photos of press-in process of an anchor2

A = 126.6 cm
Fig. 3

Geometrical properties of anchors

3. Push-in and pull-out experiments
3.1. Experimental procedure
In PI & PO test, first, the anchor was pressed(pushed) into the model ground with its head closed

Fig. 6Equipment for pulling out anchors(Figs. 4 and 5) to a designated depth by means of ascrew jack set on the driving rod. A load cell was placed

the equipment shown in Fig. 6. A pair of H-shaped steel

between the screw jack and the head of the driving rod tobars was placed on the soil box. And, a bearing standmeasure the push-in force. Displacement of the anchor

having a centre-hole, a centre-hole type oil jack and a

was measured using an encoder attached to the top of thecentre-hole type load cell were set on the H-shaped steel

driving rod.

bars. The pulling rod was passed through the centre-holes,

After the anchor was penetrated to a designateddepth, pull-out test was carried out subsequently, using

and its top was fixed on the top of the load cell with areaction plate, so that compression force of the oil jack- 325 -

Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

gives tension force to the anchor. In this loading system,
ground surface.
A total of 9 cases of push-in and pull-out tests werecarried out using three types of the anchors with different
penetration depths, z.
3.3. Experimental results
Fig.7 shows the relationships between the push-in

Maximum push-in force,
Pmax (N)reaction force of the anchor is not transmitted to the

Push-in force maximum

6000

S-anchorM-anchorL-anchor

5000
4000
3000

L-anchorM-anchor

2000

S-anchor
1000
0
0

100

200

300

Embedment depth of the anchor, z (mm)force, P, and the downward displacement, w, for
L-anchor. Note that w in the figure is the depth of theFig. 8head of the anchor. This is larger than the embedded

embedment depth of the anchors

Relationships between maximum push-in force anddepth of the anchor, z, by 160 mm (see Fig. 3). The three
curves are almost identical, showing a repeatability of the300

Push-in force, P (N)7000

Pull-out force, F (N)model ground.
L-anchor force

6000

PI and PO 02

5000

PI and PO 01

4000
3000
2000
1000

L-anchor

S-anchorM-anchorL-anchorM-anchor

250
200
150

S-anchor100
50
0

PI and PO 03

0

0

50

100

150

200

250

Upward displacement of the anchor, w (mm)

-1000
0

100

200

300

400

Fig. 9500

Downward displacement of the anchor, w (mm)Relationships between pull-out force and upward

displacement of the anchors

Max. pull-out force, Fmax (N)PI and PO 01 (z = 200mm)
PI and PO 02 (z = 250mm)
PI and PO 03 (z = 290mm)
Fig. 7Force from anchor (z = 250mm)

Results of push-in tests of L-anchor

Fig. 8 shows the relationships between the maximum
push-in force, Pmax, and the embedment depth, z, of theS-, M- and L-anchors. For all the anchors, experimentswith an embedment depth of 250 mm were conducted.
Hence, the relationships between the pull-out force, F,
and the upward displacement, w, of all the anchors are400

Pull-out force maximum
S-anchorM-anchorL-anchor

350
300
250

L-anchor200

M-anchor

150
100

S-anchor

50
0
0

100

200

300

Embedment depth of the anchor, z (mm)compared in Fig. 9. The peak values of F were caused byrelatively small displacement less than 10 mm in M- andFig. 10

L-anchors, although the peak F of S-anchor was caused

embedment depth of the anchors

Relationships between maximum pull-out force andby a larger displacement of 50 mm. After the peak forces,
sharp softening behaviours were observed in all theanchors.

It is seen from the comparison of Fig. 8 and Fig. 10
that:Fig. 10 shows the relationships between the(1) the maximum push-in force is much higher than the

maximum pull-out force, Fmax, and the embedment depth,z, of the anchors.

- 326 -

maximum pull-out force in each anchor

Proceedings of the First International Conference on Press-in Engineering 2018, Kochi(2) the maximum push-in force increased as the size ofthe anchor increased (Fig. 8)(3) the maximum pull-out forces of the anchors werecomparable in L-anchor and M-anchor (Fig. 9).
In the push-in and pull-out tests of anchors
mentioned above, it was not clear whether the anchor
head opened fully or not during the pull-out process.
Hence, the pull-out tests of embedded anchors werecarried out as described in the next section.

Test A: Opened

Test B: Closed

Fig. 12 State of anchor head buried. Open / Close

S-, M- and L-anchors were used again. Embedment

4. Pull-out experiments
4.1. Outline
To investigate the basic properties of the anchors

depths, z, of S-anchor were 150, 250 and 395 mm. In thefurther, only pull-out experiments of the buried anchors

That is, a total of 18 pull-out experimental cases, were

were carried out. The model sand ground and the testing

conducted.

cases of M-anchor and L-anchor, z = 200, 250, 290 mm.

procedure used in the push-in and pull-out experiments
described in Section 3 were also employed in the pull-out

4.3. Experimental results

experiments.

Figs. 13 to 18 show relationships between
pull-out force, F, and upward displacement of the anchor,w. Figs. 13, 15 and 17 are the relationships of S-anchor,M-anchor and L-anchor buried with opened head state.
Figs. 14, 16 and 18 are those with closed head state.
In each anchor, the pull-out resistance force, F,
became larger as embedment depth, z, got deeper,
regardless of the anchor head state (opened or closed)
when buried.
It is seen from comparison of Fig. 13 (S-anchor,
opened) and Fig. 14 (S-anchor, closed) that the
maximum pull-out force, Fmax, acting on the opened
anchor was larger than that on the closed anchor.
However, the force acting on the opened anchor
decreased immediately after the peak, while themaximum force acting on the closed anchor persisted
showing a favourable behaviour. Similar trends wereobserved in the cases of M- and L-anchors, except that
Fmax of the anchors with the closed head state were larger
than those with the opened head state.
Figs. 19 and 20 show the relationships between the
maximum pull-out force, Fmax, and the embedment depthof the anchor, z, in the cases of opened head state andclosed head state, respectively. Regardless of the setting
condition of the anchor heads, the maximum pull-out
force, Fmax, increased exponentially as the embedment
depth, z, increased. That is, the increasing rate of Fmax
against z became larger as z became larger.

4.2. Experiment procedure
In a pull-out experiment, the anchor was buried in
the model ground in the stage of preparation of the model
ground, as shown in Fig. 11. The anchor was buried in
the ground with its anchor head opened or closed asshown in Fig. 12. In the case of opened head condition,embedment depth, z, of the anchor is the depth of thewing. Meanwhile, in case of closed head condition, z is
depth of the top end of anchor, because it was thoughtthat the closed anchor turns around the top end of anchor
at an initial stage of pull-out process.

F

F

Test A

Test B
Pulling
wire

G.L.

Pulling
wire

z
open

close

t1
Fig. 11t1
Outline of pull-out experiment- 327 -

Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

Opened anchor
600

PO01 (z=150mm)
PO02 (z=250mm)
PO03 (z=395mm)

700
600
500

Pull-out force, F (N)Pull-out force, F (N)

800

PO03

400
300

PO02
PO01

200
100
0
-100
0

80

160

240

320

400

PO01 (z=200mm)
PO02 (z=250mm)
PO03 (z=290mm)

500
400
300

PO03
PO02

200
100
0

PO01

-100
-40

480

Upward displacement of the anchor, w (mm)Fig. 13closed anchor force

Relationship between pull-out force and upward

displacement of opened S-anchor

040 80 120 160 200 240 280 320 360

Upward displacement of the anchor, w (mm)Fig. 16

Relationship between pull-out force and upward

displacement of closed M-anchor

Closed anchor
PO01 (z=150mm)
PO02 (z=250mm)
PO03 (z=395mm)

Pull-out force, F (N)

700
600
500
400

640

PO03
PO02

300
200

PO01

100
0
-100
0

80

160

240

320

400

480

PO03

400
320

PO02

240

PO01

160
80
0
0

40

80 120 160 200 240 280 320

Upward displacement of the anchor, w (mm)Relationship between pull-out force and upward

displacement of closed S-anchor

PO01 (z=200mm)
PO02 (z=250mm)
PO03 (z=290mm)

480

-80
-40

Upward displacement of the anchor, w (mm)Fig. 14

opened anchor

560

Pull-out force, F (N)800

Fig. 17

Relationship between pull-out force and upward

displacement of opened L-anchor

opened anchor force
PO01 (z=200mm)
PO02 (z=250mm)
PO03 (z=290mm)

500

PO03

400
300

640

PO02

200

PO01

100
0
-100
-40

0

480
400

40 80 120 160 200 240 280 320 360

PO01 (z=200mm)
PO02 (z=250mm)
PO03 (z=290mm)

PO03

320

PO02
PO01

240
160
80
0
-80
-40

Upward displacement of the anchor, w (mm)Fig. 15closed anchor

560

Pull-out force, F (N)Pull-out force, F (N)

600

0

40

80 120 160 200 240 280 320

Upward displacement of the anchor, w (mm)Relationship between pull-out force and upward

Fig. 18

Relationship between pull-out force and upward

displacement of opened M-anchor

displacement of closed L-anchor

The authors expected smaller Fmax for the anchorswith the closed head state, but the experimental results
were contrary to our expectation in the cases of M- andL-anchors. One of reasons for this may be attributed torotational resistance of the closed anchor when it ispulled-out. It is difficult, however, to derive a definite
reason for this aspect at present. Hence, the experimental
results of the anchors with opened head state are
discussed in detail hereafter.

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800

S-anchorM-anchorL-anchor

700
600
500

S-anchor

400
300
200

L-anchorM-anchor

100
0
0

50

100 150 200 250 300 350 400

Embedment depth of the anchor, z (mm)Maximum force on closed anchor,
Fmax (N)Fig. 19 Relationship between maximum pull-out force on
opened anchor and embedment depth of opened anchor

Fig. 20

Maximum stress on opened anchor,
pmax (N/mm2)

Maximum force on opened anchor,
Fmax (N)Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

0.45
0.40

S-anchorM-anchorL-anchor

0.35
0.30
0.25

S-anchor

0.20
0.15
0.10

M-anchorL-anchor

0.05
0.00
0

50

100 150 200 250 300 350 400

Embedment depth of the anchor, z (mm)Fig. 21 Relationship between maximum pull-out stress andembedment depth of opened anchor

800

S-anchorM-anchorL-anchor

700
600
500
400

M-anchor

300

S-anchor

200
100

L-anchor0050

100 150 200 250 300 350 400

Embedment depth of the anchor, z (mm)Relationship between maximum pull-out force on

Fig. 22 State of ground surface after pulling out an anchor

closed anchor and embedment depth of closed anchor

5. Push-up experiments of a trap door simulating an
Fig. 21 shows the relationship between the
maximum stress acting on the opened anchor, pmax (=anchor
5.1. Outline of experiments

Fmax/A), and the embedment depth, z. As the anchor

An experimental setup shown in Fig. 23 was usedprojected area, A, decreased, the maximum pull-out

in push-up experiments of an anchor (trap door). A sandstress increased. If the maximum pull-out stress, pmax,box (width 800 mm, height 500 mm, depth 98 mm) is

depends only on the overburden pressure acting on themade of transparent acrylic plates. A trapdoor (width 80

anchor area, pmax, should be only 0.005 N/ mm when themm, made of Teflon) is set up on the bottom of the sandembedment depth z is 300 mm, for example. However

box. The trapdoor can be lifted up by 50 mm by means ofpmax on M-anchor and L-anchor reached about 10 times

a loading jack. Thus, push-up experiments of theof this value and that on S-anchor reached 50 times value

trapdoor were carried out simulating an anchor.

2

Push-up force, F, and push-up displacement, w,

of it.
Fig. 22 shows the state of ground surface after

were measured by a load cell and a dial gauge

pulling out M-anchor (z = 290mm). The heaving area ofrespectively. The anchor was pushed-up at a rate of about

the ground surface was larger than projected area of the

0.1 mm/s. Sampling frequency of the data was 2 Hz.

anchor. This tendency was more conspicuous as z was

The model ground was made from dry silica sandlarger. In order to investigate the mechanism of pull-out#3. The physical and mechanical properties of the silica

resistance of the opened head anchors in detail, push-up

sand are listed in Table 2. The internal friction angles at

experiments of a trap door simulating an anchor was

peak strength and at residual strength, p’ and r’, wereobtained from a triaxial consolidated drained shear test of

conducted.

the sand with a confining pressure, p0, of 11 kPa. Friction- 329 -

Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

angle between the trapdoor and the silica sand was

A total of four experiments were carried out withobtained from a direct shear test between them anddifferent h of 200, 300, 400 and 450 mm (Fig. 24). Fig.

estimated as 20 degrees.

25 is an example of model ground having a height, h, of

The model ground was prepared by about 50 mm

200 mm.

layers. At first, the silica sand of about 50 mm height was
put in the sand box. Next, the sand layer was tapped toadjust the sand to a predetermined dry density of d =1.512 g/cm3 (relative density Dr = 80%).

Fig. 25 Sample of model ground5.2. Image analysis of the ground deformation
The deformation of the model ground during thepush-up experiment was monitored using an image
analysis, taking an advantage of the transparent soil box.
A camera was set in front of the sand box.
Photographing interval was 2 seconds. The photos taken
Fig. 23 Photo of anchor push-up experiment setup

during the experiment were processed by using the image
analysis software “Trackpy”.

800

5.4. Experiment results
Fig. 26 shows the relationship between push-up
force, F, acting on the anchor and upward displacementof the anchor, w. The push-up force, F, increased as the

450

200

300

height of ground above the anchor. It is interesting that w
at the peak of F increased as h increased.

Dry sand400
80

Earth press.
gauge

Push-up force from LC, F (N)

500

80

Trap door (Anchor)
Load cell
Jack

50
Dial guage
Unit：mmFig. 24 Anchor push-up experiment setup
Table 2. Physical and mechanical properties of the silica sandDensity of soil particles, ρs （g/cm3）

2.632

500

h = 450mm

400
300
200
100

h = 200mm

0-5 0

5 10 15 20 25 30 35 40 45 50 55 60

Upward displacement of the anchor, w (mm)Max.dry density, ρdmax （g/cm3）

1.567

Min.dry density, ρdmin （g/cm3）

1.325

Max. void ratio, emax

0.987

Min. void ratio, emin

0.679

Int. friction angle at peak strength, p' (deg)39.6

Fig. 26

36.6

anchor and upward displacement of the anchor

Int. friction angle at residual strength, r' (deg)PU01 (h = 200mm)
PU02 (h = 300mm)
PU03 (h = 400mm)
PU04 (h = 450mm)- 330 -

Relationship between push-up force acting on theProceedings of the First International Conference on Press-in Engineering 2018, Kochi

Fig. 27 shows the relationship between the
maximum push-up force, Fmax, and the height of theground, h. It is seen from the figure that Fmax increased
exponentially with increasing h.
The calculated results will be explained andMaximum push-up force ,Fmax (N)discussed in Section 5.5.
450
400
350
300
250
200
150
100
50
0
-50

Fig. 29 Modelling of ground failure

Fig. 29 is a simple model of ground failure
0

100

200

300

400

500

Height of the ground, h (mm)mechanism. The symbols shown in Fig. 29 are as
follows:
h: embedment depth of anchor

Measured
Calculated
from overbudern pressure
Dead weight of trapezoidal soil wedge= 2 x (W1 + W2)

: unit weight of soil
W1: W1 = ×l×h×D (D: depth of anchor)
W2: W2 = (1/2)××h×htan×D angle of slip line

Dead weight of trapezoidal soil wedge+ shear forces along the slip lines= 2 x (W1 + W2 + T cos )

N: normal force acting on slip line
T: shear force acting along slip line, T=Ntan’
L: width of anchor

Fig. 27 Relationship between the maximum push-up force
Fmax and height of the ground hl: l=L/2
f: force acting on the half of anchor

5.5. Modelling of ground failure
A failure pattern of the ground was modelled

f = W1 + W2 + Tcos
F: total force acting on anchor, F = 2× f

simply from the ground behaviour obtained by the image

n: (1+K0)v/2+(1-K0)(v/2)cos(v: Effective earth pressure,analysis. Based on that, a relationship between the
maximum push-up force, Fmax, and the ground height, h,

K0: coefficient of earth pressure at rest)

is discussed.
Fig. 28 shows the traces of the soil particles(coloured lines) obtained in all the experiments until theanchor (trap door) was push-up to 50 mm. The slip lines
were identified visually, so that clear distinct of
movements of the soil particles can be found. Largeamounts of the movements of the soil particles aredetected inside the slip lines, while almost no movementsof the soil particles are found outside the slip lines.
Straight slip lines are generated from both ends ofthe anchor, the angles between the slip lines from thevertical direction are 20 degrees in all the cases
regardless of height of the ground.

In this experiment, K0 was supposed to be 1 because
the model ground was compacted by tapping.

may correspond to the influential angle, ,specified in the Standards for Design and Constructionof Ground Anchors and Commentary (JGS, 2012).  is
specified as  = (2/3), where  is the internal friction
angle of the soil. If  is assumed to be equal to r’ or p’(refer to Table 2),  ranges from 24.4 to 26.4 degrees.
This range is larger than the measured of 20 degrees.
In Fig. 27, the relationships between thecalculated maximum push-up force acting on the anchor,
Fmax, and the ground height, h, are shown together withthe measured result (○ marks). Three types of the- 331 -

Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

calculations were conducted. The black line (-) is the

It is seen from Fig. 27 that the theoretical values

dead weight of the rectangular soil only above the anchor(×) agree with the experimental values (○) qualitatively(= 2×W1). The triangle mark (△) is the dead weight ofand quantitatively.

the inverse trapezoidal soil wedge above the anchor [=Similar patterns of the ground failure seems to

2×(W1+W2)]. The cross mark (×) is the sum of the deadoccur in three dimensional conditions, as the heaving

weight of the inverse trapezoidal soil wedge above thearea at the ground surface observed in the pull-out

anchor and the vertical components of the shear forces

experiment of an anchor was larger than the project area

along the slip lines [= 2×(W1+W2 + Tcos)].

of the anchor, as has been shown in Fig. 22.

(a) h = 200 mm(b) h = 300 mm
Fig. 28(c) h = 400 mm(d) h = 450 mm

Behaviour of sand and slip line by image analysis

6. Concluding remarks
In order to investigate fundamental pull-out

pattern was simply modelled, in which an inverse

resistance mechanisms of flip-type anchors, a series ofcalculated values of the maximum push-up forces of thepush-inpull-outanchor (trap door) based on the ground failure modelexperiments of the anchors in a dry sand model groundwere in good agreement with the measured results.

were carried out. In the pull-in and pull-out experiments,

Similar patterns of the ground failure also seems to occur

the anchors with different sizes were pushed into thein three dimensional conditions.

andpull-out

experiments,

andtrapezoidal soil wedge on the anchor was pushed up. The

model ground and then were pulled out.

The authors are aware that the push-up experiments

In the pull-out experiments, the anchors werein this paper do not perfectly reproduce behaviours of theburied in the model ground with its head opened or

ground of an actual anchor, in which soil particles moveclosed. The pull-out resistance of anchors with closed

into a cavity created under the anchor.

head state was larger than those with opened head state,

Further experiments including vertical pull-out

contrary to the authors’ expectation. Although a reason

experiments using flip-type model anchors, diagonal

for this result may be attributed to rotational resistance ofpull-out experiments of the anchors, and pull-out

the closed anchor when it is pulled-out, further

experiments of the anchors in slopes in two and three

investigation is needed for this aspect.

dimensional conditions are planned to be conducted in

Furthermore, push-up experiments of a trap door

our future research.

simulating an anchor were carried out, in order toinvestigate mechanisms of the pull-out resistance ofanchors in more simplified experimental conditions(plane strain conditions). An image analysis of theground deformation was employed in the push-up
experiments. Based on the image analysis, ground failure

Reference
Anchoring Rope and Rigging Pty Ltd. 2018. Hulk Earth
Anchors, http://www.hulkearthanchors.com/.
Japanese Geotechnical Society. 2012. Standards fordesign and construction of ground anchors andcommentary. JGS 4101-2012. (in Japanese)- 332 -