Failure mode of rainfall-induced landslide of granite residual soil, southeastern Guangxi Province, China

Abstract

Abstract. Granite residual soil landslides are widely distributed in the southeast of Guangxi, China. They pose threats to local communities, economic development and ecological restoration. To understand the failure mode, the landslide can provide a scientific basis for early warning and prevention. In this study, we conducted artificial flume model tests to investigate the failure mode of granite residual soil landslide. The macroscopic phenomena of landslides were observed and summarized. The response and variations of soil moisture content and pore water pressure were analyzed. And the discrepancies in landslide initiation were explored. The results had three aspects: (1) the response of volume moisture content was not synchronized with that of pore water pressure. Their variations were influenced by initial dry density, slope angle and rainfall intensity. The fluctuation of pore water pressure depended on soil mechanical behavior and its diffusion. (2) The differences in the formation process of granite residual soil landslides included the initiation time and mode. The starting time of landslide was delayed with increasing initial dry density and slope angle but shortened with increasing rainfall intensity. The failure mode could be changed from a sudden type to a progressive type due to the increase in initial dry density. (3) There are five stages in the landslide mobilization as follows: rain infiltration and crack generation, soil slide at the slope toe, occurrence of surface runoff and soil erosion, formation of steep-free surface, and soil slide at the upper slope. This research can provide valuable reference for the prevention and early warning of granite residual soil landslide in southeastern Guangxi.

Pencirian Geohazad Tanah Runtuh Pendam Lama di Kawasan Bukit Fraser, Pahang

“…Permukaan batuan granit mengalami proses luluhawa yang tinggi, menghasilkan tanah baki. Keadaan ini sesuai untuk berlakunya tanah runtuh (Hirata & Chigira 2019;Saffari et al 2019;Wu et al 2022). Lapisan tanah baki tebal meliputi lebih daripada 80% kawasan tanah di Malaysia (Saffari et al 2019), lebih daripada 75% permukaan di Malaysia diliputi oleh tanah baki terurai daripada granit, sedimen dan metasedimen serta lebih kurang 50% permukaan tanah di Semenanjung Malaysia terdiri daripada batuan granit (Abdul Samad et al 2018).…”

A review of impacts of soil rock fragments on slope erosion: Mechanism and processes

“…In this sense, with the emergence of a free surface on a slope (mostly through manual excavation), the erodibility of lower coarse‐textured layers on the free surface is more susceptible to erosion and prone to forming depressions under waterfall flow erosion, creating a niche‐shaped gully head (Figure 6b), and triggering the formation of large gullies through repeated collapse and regeneration (Figure 6c) (Bacellar et al, 2005; Gao et al, 2022; Liu et al, 2021; Xu et al, 2016). Additionally, moisture‐rich coarse‐textured layers might create a sliding surface across the slope, potentially leading to larger‐scale geo‐hazards, such as landslides and mudslides (Elkamhawy et al, 2018; Wakatsuki et al, 2005; Wu et al, 2022).…”