STUDY OF SLOPE STABILITY DYNAMIC ANALYSIS ON FILL AND EXCAVATION USING FINITE ELEMENT METHOD

• Main Author: LAMBANG GORO (NIM 25003013); Pembimbing: Ir. I Wayan Sengara, M.Sc., Ph.D., GARUP
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/20126
• Institution: Institut Teknologi Bandung

One of many causes of slope failure on fill and excavation is earthquake. Many seismic slope stability methods are used for slope stability design, but every method had advantages and disadvantages. One of the simple and common methods is Static Equivalent Analysis in which transient earthquake acceleration is made equivalent to a uniform horizontal force. Besides there is no representative earthquake characteristics are modeled, limitation of this method is a difficulty in assigning an appropriate seismic reduction factor. It is considered that the more realistic method is Dynamic Analysis using finite element method, which apply input motion as seismic load. The advantage of the method which in this case by using Geo-Office computer program is it can produces minimum safety factor along the impact duration of earthquake. <br /> <br /> <br /> This study compares between Static Equivalent Analysis and Dynamic Analysis on a fill and excavation models on Hard Site Classification SC, Medium/ Stiff Site Classification SD and Soft Site Classification SE following the site classification according to UBC 1997. Depths of based rock are assumed at 30m and 100m. Earthquake input motion that are applied at base rock are of type subduction and strike-slip, with peak based acceleration vary from 0,1g to 0,4g. The research also determines a reduction factor (fR) on fill and excavation model that can be used for Static Equivalent Analysis in order to produce safety factor that is similar to minimum dynamic safety factor. In this research, Static Equivalent Analysis is conducted by using a computer program PLAXIS whereas Dynamic Analysis is conducted by computer program Geo-Office. <br /> <br /> <br /> The research results show that static equivalent safety factor is always lower than dynamic minimum safety factor or it can be said that Static Equivalent Analysis is more conservative than Dynamic Analysis. By Peak Based Acceleration 0,2g on strike-slip mechanism, the seismic reduction factor (fR) for fill case over Hard Site is about 0,62, for Medium Site case, fR is about 0,2 and on the fill over Soft Site had fR is about 0,18. On the other hand, in the excavation case on Hard Site, fR is about 0,8, fR of Medium Site is below the value of Hard Site, is about 0,5 and for Soft Soil, the recommended fR is about 0,3. <br /> <br /> <br /> Continued research should be conducted for more detail fR determination on every Site Classification. Parameter range of Vs and Cu according UBC 1997 are wide enough, it needs divided by some values of Vs and Cu therefore will produces representative fR value for a Site Classification. And for produces more accurate result, it needs using soil parameter values from laboratory test result.