Groundwater influence to slope stability analysis at main road of Malino-Manipi, Indonesia

摘要

Malino-Manipi main road is a short cut way to connect western and eastern part of South Sulawesi Province Indonesia. This road crosses the Bawakaraeng Moutain in which suffer easily with slope failure particulary in rainy season. To understand the slope condition, it was studied to develop new design for the slope to meet standard of safety factor. A field study have been done to observed actual slope at present condition. The slope consist of volcanic tuff with mechanical properties of unit weight (??) is 20.336 kN/m3; cohesion (c) is 4.089 kN/m2; and internal friction is (??) 34.314o. The slope stability analysis was performed by using finite element method of Phase2-6.0 software. Simulation result showed the estimated of safety factor (SF) in actual slope without considering the groundwater influence is 0.503 and by considering of groundwater level became 0.473. This simulated result shows that factor of safety actual slope indicated the slope in unstable condition. In order to overcome the problem, redesign of slope geometry is needed. A new design of slope was proposed consisting 4 benches with bench height is 8.5 meters, bench width is 6 meters, overall slope is 37O and single slope is 53O. Simulation without considering the groundwater level estimated SF of 1.396 and 1.268 for 500 and 1,500 element respectively, whereas by considering groundwater level resulted SF of 1.343 and 1.250. This simulation was also figure out distribution of mean stress, maximum shear strain, and total displacement