2 Materials and methods

2.1 Sample description and preparation

The tested samples were collected from the Wujiafen (WJF) landslide, which was located at Zhuanfang village, eastern Chengdu Hi-Tech Industrial Development Zone, Sichuan Provence, China. Similar to the Leidashi (LDS) landslide in its 10° north by east about 2 km long. The WJF landslide collapsed along a gently inclined bedding plane due to heavy rainfall in August 2019 (Li et al., 2020). As the field investigation showed (Fig. 1), a sandwich rock structure consisting of red mudstone and argillaceous sandstone of the Triassic Penglaizhen Formation was revealed in the left lateral scarp of the WJF landslide. Intact mudstone and sandstone with slight weathering were sampled by avoiding a soft interlayer (pressed in by the cutting ring) that was parallel to the sliding direction. The physical and mechanical properties of the rock samples in Table 1 were determined in laboratory tests.