Experimental Study on the Evolution Mechanism of Landslide with Retaining Wall Locked Segment

Abstract

The failure of locked segment-type slopes is often affected by rainfall, earthquake, and other external loads. Rainfall scours the slope and weakens the mechanical properties of rock-soil mass. At the same time, rainfall infiltrates into cracks of slope rock mass. Under the action of in situ stress, hydraulic fracturing leads to the development and expansion of rock cracks, which increases the risk of slope instability. Under seismic force, the slope will be subjected to large horizontal inertial force, resulting in slope instability. In this paper, a self-developed loading device was used to simulate the external loads such as rainfall and earthquake, and the model tests are carried out to study the evolution mechanism of landslide with retaining wall locked segment. Three-dimensional laser scanner, microearth pressure sensors, and high-definition camera are applied for the high-precision monitoring of slope shape, deformation, and stress. Test results show that the retaining wall locked segment has an important control effect on landslide stability. The characteristics of deformation evolution and stress response of landslide with retaining wall locked segment are analyzed and studied by changing the slope shape, earth pressure, and the displacement cloud map. The evolutionary process of landslide with retaining wall locked segment is summarized. Experimental results reveal that as the landslide with retaining wall locked segment is at failure, the upper part of the landslide thrusts and slides and the retaining wall produces a locking effect; the middle part extrudes and uplifts, which is accompanied with shallow sliding; and compression-shear fracture of the locked segment leads to the landslide failure.

Experimental study on tilting deformation and a new method for landslide prediction with retaining-wall locked segment

“…Wang et al 44 determined that the tangential angle of displacements–time curve before landslide instability was generally 89°–89.5° through statistical analysis, which was used as one of the early warning and prediction criteria of landslides. They proposed the displacement tangential angle criterion, and the value of tangential displacement angle was further determined through coordinate axis transformation 41 . The angle–time curve of a landslide is consistent with the displacement–time curve, and both have typical creep characteristics that can be divided into three stages.…”

“…Relevant studies have shown that the locked segment is of low brittleness 39 . Based upon the existing studies of locked-segment type landslides 40 , 41 , water, gypsum, and sand were selected to simulate the retaining-wall type locked segment with a mass ratio of 1:1.4:1. According to the same ratio of the cylindrical sample, using YAW6206 electro-hydraulic servo press to carry out a uniaxial compression test, the uniaxial compressive strength was 3.27 MPa.…”

“…After the landslide enters the tertiary creep stage, the tangent angle is much greater than 45°. According to relevant studies and the summary of landslide cases 41 , when the tangent angle of the landslide ( 3) www.nature.com/scientificreports/ is > 80°, the landslide deformation is significantly accelerated. When the tangent angle of the landslide is > 85°, the landslide shows signs of an impending slide, the deformation rate sharply increases, and the landslide becomes unstable and slides in the near future.…”

Study on deformation and failure characteristics of oblique-cut locked rock slope under rainfall conditions

“…Some scholars have pointed out that 20 any part that controls the stability of the slope can be defined as the ‘locked segment’, so the ‘locked segment’ is the key to analyzing the progressive failure of many slopes. Aiming at the locked landslide in the western region of Henan Province, China, Liu Handong et al 21 used a self-developed loading device to simulate external loads such as rainfall and earthquakes and carried out the evolution mechanism of the ‘retaining wall’ type locked segment landslide. Li Dongdong et al 22 carried out a series of large-scale landslide physical model tests using specific flume test equipment and tested the difference between the failure time and deformation behavior of the three locking section shapes under the same rainfall conditions.…”