Integrated Geophysical Method, Standard Penetration Test, and Remote Sensing for Interpreting, Correlating, and Analysing Cause of Landslides from Irrigation Pipe Leakage, Case Study: CBLP Hydro Power Plant

Abstract

CBLP Hydro Power Plant has experienced landslide that caused damage to waterway structure. Relocation of waterway was done in order to move into a more stable area. However, this solution is ineffective wherein the southern part of waterway still encounters landslide. Integration of 2.5D Electrical Resistivity Tomography (ERT), 3D Vertical Electrical Sounding (VES), Very Low Frequency (VLF), Standard Penetration Test (SPT), and digital elevation model from Remote Sensing are carried out to determine lithology, hydrology, topography, and determine local anomaly of research area. From VES model, the lithology consists of landslide material, breccia altered into sandstone with high water content, and massive breccia. From ERT model, we found a shallow anomaly of low resistivity in line 3 and 7. This anomaly is validated by doing 2 meters deep excavation and found a rapid flow of water caused by a leak from irrigation pipe. VLF model is used to validate water leakage continuity. In conclusion, northern part of waterway is relatively safe due to water leakage continuity absence, with relative density of 34 (SPT) and resistivity number 6.87 μm, whereas the southern part of waterway is high risk because affected by continuity of water irrigation pipeline leak.