10th Asian Regional Conference of IAEG (2015)

RELATIONSHIP OF SOIL PROPERTIES AND DYNAMIC LOAD TO DETERMINE TYPE
OF LANDSLIDES IN SUMEDANG REGENCY WEST JAVA INDONESIA
Siska FEBYANI 1 , Novianti PURASONGKA1*, Raden Irvan SOPHIAN1, Dicky MUSLIM1 ,Fitriani Dewi APRILIA1, Delyusar2
1

Geological Engineering Laboratory, Padjadjaran University,Bandung 45363, Indonesia
2Pusat Pengembangan dan Penelitian Geologi Kelautan*E-mail : noviantiwahyunipurasongka@ymail.com

Abstract
Ciherang village is located in Sumedang, West Java Province, Indonesia. The village is very
strategic because it connects the two major cities in West Java. Geology of research area consistsof Formation Qvb (old volcanic breccia), Qyu ( undefined young volcanic consist of tuffaceous
sand, lapilli, breccia, lava, and agglomerates). The study was conducted to determine the type oflandslide, as well as the role of dynamic loads to landslide in the research area. The methods usedin this research are the interpretation of topographic maps, satellite image, engineering
geological mapping to determine the distribution of soil types, joint data, soil horizon, disturbed
soil sampling (USCS classification, basic and mechanical properties), and the slope geometry
measurement. Based on the results of soil description, location A has dark-colored soil, with finesand grain size, poor sorting, subrounded gravel, having organic content, middle plasticity, andthe average value of slope is 570. At location B the soil is blackish brown soil, fine particle grainsize, subangular gravel, middle plasticity, and the average value of the slope is 450. Type oflandslide in this area can be classified into translational landslide. Another factor that led to thelandslides is due to dynamic loads that exist on the main road crossing the study are, such as
heavy – weight trucks more than 20 ton that pass through the connecting road between Cirebon Bandung which give rise to vibration.
Keyword : type of landslide, soil description, engineering geology, dynamic load.

1.

Introduction

Based on the map of geology regional Bandung(P.H Silitonga, 1973) the study area consists of the ofFormation Qvb (old volcanic breccia), Qyu (undefined
young volcanic consist of tuffaceous sand, lapilli,breccia, lava, and agglomerates).

Ciherang village is located in Sumedang, WestJava Province, and it connects the two major cities inWest Java. In geomorphology this area is located on
the slopes of the mountain with an altitude of 720 m
above sea level.

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10th Asian Regional Conference of IAEG (2015)

load can be either an earthquake or human activities(vehicle traffic).
Table 1. Types of Landslide
No
1.

Type
Falls

Subtype2.

SlidesRotationalPlanarFigure 1. Location of research area
3.
2.

Landslide

FlowsDry
Moderatelywet
Very wetSlopes are a natural surface appearance which has aheight difference. If the height difference of the twoplaces compared with the straight distance horizontally,
will obtain the magnitude of gradients (slope). Slope
shape depending on the movement of soil erosion andweathering. Slope topography parameters are divided
into two parts, the slope and the height difference ofrelief. Slope stability is closely associated withlandslides or ground movement which is the process ofmass transfer of land naturally from a high place to alower place.

3.

Description– Rockfall (bedrock)– Soifall(Loose material)– Slump (bedrock orcohesive units ofmaterial– Block-glide (bedrockor cohesive units Loosemterial)– Rockslide (bedrock)– Debris slide (loosematerial)– Rock avalanche– Sand run– Loes flow
– Debris avalanche– Earth flow
– Sand or silt flow
– Debris flow
– Mud flow

Methods

The method used is the interpretation of topographic
maps, satellite imagery, geological mapping techniques,soil sampling later be described and classified based on
USCS standards, and measuring the slope geometry.

This soil movement occurs due to changes in thebalance of the soil bearing capacity and will stop after
reaching a new equilibrium. Landslide is a slide orsliding or falling of the rock mass / ground or a mixtureof both (Sharpe,1938 in Hansen, 1984). Landslides
generally occur if the ground is not able to withstandthe weight of the soil layer on top of it because no
additional load on the slope surface and reduced powertie between soil grains relief. Varnes (1978) classified
the movement of the soil into six (6) types based on themechanism and material (Table 1).

4.

Result

The type of soil in the research area is the result ofvolcanic eruptions. This soil has a red in color, clay tosand in grain size, fertile, so that the rapidly growing
settlements in this area. Based on the results of soil
description, location A has dark-colored soil, with finesand grain size, poor sorting, subrounded gravel,
having organic content, middle plasticity, and theaverage value of slope is 570. At location B the soil isblackish brown soil, fine particle grain size, subangulargravel, middle plasticity, and the average value of theslope is 450. Based on USCS classification, this soil
including to sand poorly gradded (SP). This type of soil
when it rains, water will infiltrate into the soil cracks
that quickly expands back accumulates at the bottom of
the slope, causing lateral movement, it is because it
separated and semi plastic. Slope with high slope will
increase the propulsive force than the retaining force.
Based on sliding plane, type of landslide in researcharea is translational landslide.

Some important parameters as the trigger
landslides, among others, is the slope. The greater theangle of slope the greater the thrust due to increased
shear stress is inversely proportional to the normal
stress in the form of retaining strength. Besides thedynamic load will also affect the magnitude of the tilt
angle. In areas that have a high dynamic load effects,
then the angle of the slope should be smaller than thearea of influence of the low dynamic loads. Dynamic

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10th Asian Regional Conference of IAEG (2015)

Figure 2. Location AA

Figure 3. Location BBFigure 4. Translational Landslide Model

Beside landslides, other types of ground movement thatdevelops is creep. Creep is a type of slow-moving.
Grain size soil is coarse and fine. Type of this landslideis almost unrecognizable. After quite a long time creep
landslide types can cause telephone poles, trees, orhouses tilted. In Ciherang village house started
cracking and the floor separately.

CFigure 5. A,B,C. Impact of Creep Movement

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5.

References

Conclusion and Discussion

Hansen, M.J., (1984), Strategies for Classification ofLandslides, (ed. : Brunsden, D,& Prior, D.B., 1984,
Slope Instability, John Wiley & Sons, p.1-25
Bowles, JE.,(1989): Sifat-sifat Fisik & Geoteknis Tanah,Erlangga, Jakarta, 562 hal.
Zakaria,Zulfiadi.( 2009): Analisis Kestabilan Lereng
Tanah. Engineering Geology University of
Padjadjaran.
Varnes, D.J., (1978): Slope Movement and Types andProcesses, In Landslide: Analysis and Control.
Transportation Research Board.
Silitonga, P.H. (1973). Regional Geological Map ofBandung. Puslitbang. Bandung.

The type of soil found in the area of research is theresult of volcanic eruption. This soil has a red in color,sand and clay grain size, and fertile. The type of soil
which is less dense when it rains, water will infiltrate
into the soil cracks that quickly expands backaccumulates at the bottom of the slope, causing lateral
movement, it is because it is separated by a semi plastic
plasticity level. Slope with high slope will increase theretaining force than the driving force. Population
density was a contribution of ground movement due toload that exceeds the soil makes the soil lose theconnective power, so comes the movement of soil.
governance paddy fields, cultivation, and the puddles
on the steep slopes developed in this area. At the rootof paddy fields strong enough to bind the grains of soil
and make the soil becomes soggy and saturated withwater so it is easy to landslides. Because Ciherangvillage located on the side of the road between theprovinces of heavy vehicles such as buses, trucks,
minibus passing from morning to night and vice versa
then generate vehicle traffic vibration. Consequences
thereof is ground, road, floors, and walls cracked.
6.

Acknowledgement

Thanks to Faculty of Engineering Geology that easy in
our research. And Sumedang District Government thathas given permission to conduct research. Thanks to Mr.
Delyuzar (Pusat Pengembangan dan Penelitian Geologi
Kelautan) for funding this research.

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