Back-analysis of ground movement based on displacement matching approach : a case study of landslide at bridge abutment using 3D finite element method

Abstract

Phenomena of slope movement were identified on the southern side of Penggaron Bridge, which is Abutment 2 (A2) and Pier 9 (P9), at the end of 2011. Geotechnical instrumentation gives a result that the landslide movement is instead directed toward the North-East direction. A common way of backanalysis is by assuming that the Safety Factor (SF) is equal to unity through a defined sliding plane. Nevertheless, the fact is that the movements are still limited, and the residual strength is to be determined. Hence, a threedimensional landslide back-analysis is performed to assess the slope stability for such a particular condition. A new back-analysis approach, namely the displacement matching method, is introduced and briefly explained. The results show that the method is prospective to be used, especially for the assessment of the existing Safety Factor of the slope. This study gives a better illustration of the real safety factor.