Experimental study on disaster mechanism of completely weathered granite landslide induced by extreme rainfall

Abstract

Background With the increased frequency of extreme weather, landslides induced by extremely heavy rainfall pose a major threat to human lives and property safety. In July 2020, a landslide occurred in the strongly weathered Laoshan Scenic Spot in Qingdao, China, and a short period of heavy rainfall was the main factor inducing the landslide. Method Based on the similarity criterion, three groups of laboratory model tests under different extreme rainfall conditions were conducted using a large landslide model test box. The rainfall infiltration responses under different rainfall intensities, deformation processes, and failure modes of the slope were analyzed. The inducing mechanism and rainfall disaster process of granite landslides induced by extreme rainfall in strongly weathered areas were summarized. Result The results showed that (1) a completely weathered granite landslide induced by rainfall had four stages, i.e., infiltration erosion, surface deformation, damage deepening, and overall instability, and the landslide was characterized by "sheet slip". (2) With greater rainfall intensities, the rainfall infiltration rate was higher, the changes in soil pressure, pore water pressure, water content, and matrix suction were faster, and the hysteresis effect was weaker. (3) A certain spatial distribution pattern was observed between slope deformation/damage and rainfall infiltration, and the research results could provide references for landslide warning and treatment in strongly weathered granite areas.

Study on Fluid–Solid Coupling Numerical Simulation and Early Warning of Weathered Granite Landslides Induced by Extreme Rainfall

“…In this example, soil displacement starts from the middle of the slope and gradually develops towards the top of the slope, and finally deformation occurs at the bottom of the slope. This means that the top of the slope undergoes deformation first, and it can be inferred that the landslide is a thrust-type landslide, which is consistent with the results of physical model tests [32]. Under different rainfall intensity conditions, the rate of pore pressure increase at the same monitoring point is significantly different.…”

“…According to the survey report data of the Fanling landslide [32], 3D rainfall fluidsolid coupling modeling [33,34] of the main sliding surface of the landslide is carried out. The geological profile is shown in Figure 6.…”

“…Due to the high degree of weathering and soft rock and soil strength, fully weathered granite slopes are prone to instability under extreme rainfall conditions. In previous studies, the author has conducted three sets of large-scale physical model tests (Figure 1) on the fully weathered granite landslide in Fanling under different rainfall conditions and preliminarily summarized the mechanism and failure process of rainfall-induced fully weathered granite landslide [32]. This paper is a follow-up study.…”

Experimental Study on Runoff and Sediment Production of the Fully Weathered Granite Backfill Slope under Heavy Rain in Longling, Yunnan Province

“…The proportion of surface runoff increases with the rainfall intensity, while the variation in proportion is relatively small with changes in slope gradient. These findings have certain guiding significance for the study and management of soil erosion in granite areas [36,37]. However, the slope erosion characteristics, erosion patterns, and controlling factors of slopes composed of completely weathered granite and its backfill soil are still not well understood.…”

Numerical Simulation Study on the Spacing of Landslide Anti-slip Piles Based on Strength Reduction Method

“…The Huiling landslide is in Laoshan District, Qingdao City, Shandong Province, China. The area has a high degree of weathering and is a typical fully weathered granite landslide [12]. In August 2020, under the influence of rainfall, the landslide was damaged [13].…”