10th Asian Regional Conference of IAEG (2015)

The Zonation of Static Shallow Foundation Bearing Capacity on Educational Area of
Padjadjaran University, Sumedang District, West Java, Indonesia
Yogi PRIANDA PUTRA(1), Muhammad Fajar FAHREZA(1), Raden Irvan SOPHIAN(1), Dicky
MUSLIM(1), Zufialdi ZAKARIA(1), and Agus Wiramsya OSCAR(2)(1) Engineering Geology and Geotechnics Laboratory, Faculty of Geological Engineering,
Padjadjaran University,
Bandung-Sumedang Street Km 21, 45363, Sumedang, Indonesia
E-mail : yogiprianda104.geounpad10@gmail.com
E-mail : mfajarfahreza@gmail.com(2) Faculty of Geological Engineering, Padjadjaran University
Bandung-Sumedang Street Km 21, 45363, Sumedang, Indonesia
Abstract
Research area is included in the zones of Undifferentiated Young Volcanic Productsof Mount Tangkubanparahu and Lake Deposits of Bandung Ancient Lake. The study wasconducted in the educational area of Padjadjaran University. The object of the research isbasic and mechanical properties of soil. Administratively, the research area is included in
the district of Jatinangor, Sumedang Regency, West Java Province, Indonesia. This study
aims to investigate the mechanical and physical properties of soil with undisturbed sample
depth less than 1 meter. Afterwards, the samples through the triaxial UU test to find out themechanical and the physical properties of the soils. The value of c (cohesion), ϕ (angle ofinternal friction), and ɣ (unit weight) converted to be the value of bearing capacity by using
the formula which is introduced by Terzaghi. Based on calculations for shallow foundationin general shear condition and local shear condition indicates that the highest value inallowable bearing capacity (qa) was in square foundation in one meter depth. The zonationsof bearing capacity data is divided into five zones, they are; less than 3 tons/m2 zone, 3 – 4tons/m2 zone, 4 – 5 tons/m2 zone, 5 – 6 tons/m2 zone, and more than 6 tons/m2 zone. The
foundation type suggested in the research area is square foundation with one meter wide
and one meter depth.
Keywords: Bearing Capacity, Soil Mechanics, Foundation Type, Zonation of Bearing Capacity
1.

determining the safety factors level of an
infrastructure that will be built on it. The study ofengineering geology is necessary to help us determine
the safety factor of the area that will be used todevelop an infrastructure. The physical properties andmechanical properties of soil and rock can be used asa base of consideration in decision making for theimplementers and regional development planners.

Introduction

The research area is included in the district ofJatinangor, Sumedang Regency, West Java Province,
Indonesia (figure 1). Jatinangor district is a district
that belonging to the rapidly infrastructure growing
sector. It is directly proportional to the level ofdeveloping land use. 3 units of apartments and someeducational buildings already built within a period offour years. This is done to meet the needs ofeducational and residency sector.
Soil as the foundation plays an important role in[Figure 1]

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10th Asian Regional Conference of IAEG (2015)

Types of laboratory tests conducted to determine
the physical properties of soil including the moisture
content test, unit weight test, specific gravity test, theliquid limit test, plastic limit test, hydrometer analysis
and sieve analysis. And the type of laboratory tests
conducted to know the mechanical properties of thesoil is a triaxial UU test. All laboratory tests adaptedfrom ASTM (American Standard Testing andMaterials).
Ater that the mechanical properties parametersof soil (c, ߮, and ɣ) processed to obtain the value ofsoil bearing capacity using this following Terzaghi
formula :2.

Geological Background
Based on Silitonga (1973), the stratigraphy of
Jatinangor area from the oldest to the youngest asfollows (figure 2) :1. Undifferentiated Young Volcanic Products(Qyu) in the form of tuffaceous sand, lapili, lava,
agglomerate mostly from Mt. Tangkubanparahuand Mt. Tampomas. Between Bandung andSumedang this unit expressed as a flat or low
hill area covered by yellowish gray to reddish
gray soil,
2. Lava of Young Volcanic Products (Qyl) in theform of lava,
3. Lake Deposits (Ql) in the form of tuffaceous
sand, sandstone, gravel and conglomerate.
Locally form horizontal layers. Contains
limestone concretions, plant remains, fresh
water molluscs, and bones of vertebrates.
Locally also intercalated by breccia.
In the field, the outcrop condition already highlyweathered.

qa = qult / F(1)

Where qa is the allowable bearing capacity value,
qult is ultimate bearing capacity value, and F is factorof safety.
Factor of safety that used in this research is 3.
The foundation built above the seepage. The general
shear failure of continuous footing simulation used todetermine the bearing capacity because thissimulation produce the lowest bearing capacity value,
which has the following formula :[Figure 2]
3.

Methods
The research is done by using guide based onengineering geological mapping, basic properties test,
triaxial test and mechanical properties calculation
using Terzaghi formula to determine the bearing
capacity of soil.
As the definition by Dearman (1991),engineering geological mapping is one of geology
applied discipline to civil engineering. What should
be shown on an engineering geological map depends
on its purpose. The basic map information is needed
to assess the feasibility of a proposed engineering
construction. Map type that used in this research islithological type (LT). Typically the scale of suchmapping is 1 : 5000 to 1 : 10.000. Engineering
geological mapping aimed to obtain information on
the deployment of soil based on the characteristics ofUnified Soil Classification System (USCS). Thismapping can be tentative or provisional because thefield description of soil dominated by subjectiveapproaches. The correction will be obtained byconducting laboratory tests on undisturbed samples.
All methods of undisturbed soil sampling adaptedfrom ASTM D 1452.

qult = (c . Nc + γ Df . Nq + 0,5 γ . B . N γ)

(2)

Where qult is ultimate bearing capacity value,and c is cohesion, ɣ is unit weight of soil, Df is thedepth of foundation, B is width of foundation, and Nc– Nq - Nɣ is bearing capacity factors.
After the bearing capacity data process complete,bearing capacity data are plotted on a map according
to undisturbed soil sampling coordinate. The zonation
made by using kriging method.
4. Result4.1. Engineering Geological Map
Based on the results of geological mapping
techniques and laboratory testing with reference
USCS, the study area can be divided into fiveengineering geological units (figure 3) as follows :1. Silt with High Plasticity (MH)
2. Silt with Low Plasticity (ML)
3. Clay with High Plasticity (CH)
[Figure 3]

210th Asian Regional Conference of IAEG (2015)

soil acquired from plastic nature owned by clay
particles. The different types of soil is influenced byrock origin.
The differences in percentage of soil grain size
affects the formation of soil types. It also affects themechanical characteristics of the soil because thepercent of clay affect the value of soil cohesion. The
percentage of soil grain size also affects the value ofthe friction angle because the grain size affects
whether the relationship between the grains in the soilinterlocking or not.
This research area is suitable for development ofinfrastructures as long as the weight of theinfrastructures does not exceed the allowable bearing
capacity. If we want to build a building with load
exceed allowable bearing capacity, we should
increase the depth of the foundation required.

4.2. Bearing Capacity Values
There are 18 samples taken in this research. it
spread in the educational area of Padjadjaran
University. All of it processed by triaxial test to
determine the mechanical properties parameters.
After that, the machanical properties parameters
processed by using Terzaghi formula to obtain thebearing capacity values.
[Table 1]
4.3. The Zonation of Shallow Foundation Bearing
Capacity
The zonation of shallow foundation bearing
capacity at 1 meter depth is based on the lowest
values of the soil bearing capacity. In this study, thelowest qa value obtained from simulations using
continuous type of foundation on the general shear
failure condition. The range of bearing capacity inthis study area is from 2.12 to 6.31 tonnes / m2. The
value range can be classified into five groups (figure4), as follows :1. Zone of allowable bearing capacity (qa) < 3tonnes / m2. This zone is spread in theNorthwest and Southwest areas of research,
2. Zone of allowable bearing capacity (qa) 3-4
tonnes / m2. This zone is spread in almost allparts of the study area, as follows the Central,West and Northwest,
3. Zone of allowable bearing capacity (qa) 4-5
tonnes / m2. This zone is spread across parts of
the Southeast, Central, and Northern areas ofresearch,
4. Zone of allowable bearing capacity (qa) 5-6
tonnes / m2. This zone is located on theNortheast and Central regions of research,
5. Zone of allowable bearing capacity (qa) > 6tonnes / m2. This zone is located in the Central
part of the study area.

References
Anonymous (2008). Triaxial UU (UndrainedUnconsolidated) ASTM D - 2850-95. PA : ASTM
International, West Conshohocken.
Das, Braja M. (1999): Shallow Foundations : Bearing
Capacity and Settlement, 1st edn. CRC Press LLC,Florida, p. 16.
Dearman, W.R. (1991) Engineering geologicalmapping. Butterworth-Heinemann, Oxford, 387p.
Silitonga, P.H. (1973). Systematic Geologic Map,
Jawa, Bandung Quadrangle Scale 1 : 100.000.
Geological Research and Development Centre,Bandung.
Zakaria, Zufialdi (2006). c and ϕ for Shallow
Foundation Bearing Capacity. Faculty ofGeological Engineering, Padjadjaran University,
pp. 7-9.

[Figure 4]
5.

Conclusions
Besed on geology condition, research area isdominated by volcanic material such as tuff, volcanic
breccia and tuffaceous sandstone. The residual soil isis dominated by fine grains. With a high content offine grains, the soil has a plastic nature. Plasticity in3

10th Asian Regional Conference of IAEG (2015)

Fig. 1 The location of research area (taken by google earth, April 29th, 2015)4

10th Asian Regional Conference of IAEG (2015)

Fig. 2 Geology Condition of Research Area (modification from Silitonga, 1973)

Fig. 3 Engineering Geological Map of Research Area510th Asian Regional Conference of IAEG (2015)

Table 1 qult and qa of all samples calculate in general shear failure of continuous footing simulation in one
meter depthLaboratory Test Result

Bearing Capacity

SampleCodes

Z1aBT1Z1aBT2Z1bBT1Z1bBT2Z2aBT1Z2aBT2Z2aBT3Z2bBT1Z2bBT2
Z3BT1
Z3BT2
Z3BT3
Z3BT4
Z4BT1
Z4BT2
Z5BT1
Z5BT2
Z5BT3General Shear Failureϕ(Angle ofInternalFriction)c(Cohesion)

qult(tonnes/m2)

qa(tonnes/m2)(°)

kg/cm2

16,71
13,38
6,75
10,45
14,9
20,4
13
12,24
15,99
11,85
18,94
15,47
17,43
12,42
10,36
13,53
17,58
6,37

5,57
4,46
2,25
3,48
4,97
6,8
4,33
4,08
5,33
3,95
6,31
5,16
5,81
4,14
3,45
4,51
5,86
2,12

4,826
3,453
4,116
3,625
4,863
4,785
3,81
4,057
4,036
3,634
6,146
5,672
3,972
5,424
4,18
3,431
2,834
3,552

0,206
0,175
0,062
0,122
0,178
0,264
0,16
0,147
0,254
0,147
0,209
0,1680,232
0,106
0,150,181
0,2560,058

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10th Asian Regional Conference of IAEG (2015)

Fig. 4 The zonation of static shallow foundation bearing capacity on Educational Area of PadjadjaranUniversity7