Field Geological Investigations and Stability Analysis of Duanjiagou Landslide

Abstract

This paper analyses the stability of the Duanjiagou landslide on the Bazhong to Guangan Expressway K134–K135 segment in China. The Duanjiagou landslide took place on 4 November 2015. In order to discover the cause of the landslide, we carried out field geological investigations. The indoor physical property experiments were performed by taking the undisturbed soil sample from the borehole cores. To study the strength of the soil, we carried out a saturation direct shear test and saturation residual shear test on sliding zone soil samples. According to the physical properties of soil and the saturated shear strength parameters of sliding zone soil, the stability was analyzed by the landslide force transmission method and numerical simulation method. The results showed that in the initial sliding stage, the safety factor obtained by using the average value of saturated shear strength parameters was in good agreement with the field observation situation. The landslide was at an unstable state. The softening of soil and roadbed excavation at the foot of the slope are the main reasons for landslides.