Analysis slope stability of transmission tower 150 kV on moderately-cemented-sand due to soil excavation

T.66, transmission tower of 150 kV line Cilegon Baru – Asahimas was in high light for the threaten of slope stability because of soil mine excavation around tower area. Massive Excavation soil were occurring next to tower foundation, which is the depth approximately 14 m (height) and the inclination almost 80°. Therefore, analysis was highly needed to ensure that tower stand on stable spot. The method used in this research were study literature, soil investigation (deep boring and hand boring) and laboratory test for undisturbed samples, geoelectric test, and topography mapping. The type of soil was ‘moderately cemented sand’ slope. It has a complete characteristics and tends more challenging in determine the slope stability. By considering that, the data parameters input were approached in conservative way, which was considering literature and soil investigation data. In this case, slope stability was modeled with Finite Element Method (FEM) by doing back analysis. The result shown that tensile stress was relative small (near 0).