RAINFALL INTENSITY EFFECT ON SLOPE STABILITY OF VOLCANIC RESIDUAL SOIL AT KERTAMUKTI AREA, SUKABUMI REGENCY, WEST JAVA (CASE STUDY: PLTM BASE)

• Main Author: Priksawan, Agditya
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/39836
• Institution: Institut Teknologi Bandung

Utilization of water energy in Indonesia has only amounted to 5,258 MW recently, therefore a hydroelectric power plant (PLTM) construction needs to be done to improve the development of water energy potential in Indonesia. The construction of PLTM Kertamukti can contribute to the utilization of the water energy potential in Sukabumi Regency by using the Cicatih watershed. This research is useful for providing slope engineering considerations related to those activities. The methods used in this research included field observations, petrographic analysis, engineering properties test of rocks and soils, rainfall duration analysis, rainfall frequency statistic analysis and slope numerical analysis. The slope used as a study is composed of the Volcanic Breccia Formation (Qvb) which is Plistocene age. The Volcanic Breccia Formation revealed in the study area is mainly consist of volcanic breccias, sandstones, tuffaceous sandstones and tuffs. Generally, these rocks are exposed in slightly-completely weathered conditions. Based on the results of rainfall intensity analysis, the maximum frequency of rainfall that may occur in the study area within 50 years return period using a normal distribution is 134 mm/day with a rainfall duration for 19 days. Based on the results of numerical analysis, changes in pore water pressure on artificial slopes occur more significantly compared to natural slopes. The simulated rainfall variations on artificial slope cause slope instability which is reflected in the decreased safety factor value up to 54.57%, while in the simulation of rainfall variations on natural slopes have reduced the safety factor only 7.55%. In this case, it appears that the slope instability is a function of the decrease in matric suction in the slope constituent material.