| The occurrence and development of the landslide is a process of gradual destruction,and causes huge losses to people’s lives and property.For the landslide,it usually occurs more than once,but after the landslide first stops,it will enter the dormant period,and self-healing and strength recovery will appear on the sliding surface.This self-healing phenomenon will have a great impact on the re-initiation of the landslide.In the analysis and calculation of slope stability,the residual strength value of slip soil is often an important indicator.The self-healing phenomenon of sliding belt soil in the stationary period is manifested as the increase of shear strength.Therefore,a series of studies on the mechanical characteristics and strength recovery change rules of sliding belt soil will be of great significance to the engineering construction,and also provide ideas for landslide control and protection.This paper explores the characteristics of the shear strength in different conditions by controlling the pause time and vertical pressure,and uses FLAC3 D software to analyze the stability of the landslide under the natural and saturated conditions,and simulate the influence of the change of the sliding belt soil strength parameters on the safety factor.The main research results are shown as follows:(1)The ring shear test showed that the shear strength in native soil is higher than that in saturated state.The peak strength and residual strength increase with increasing vertical pressure at different vertical pressures.Due to the structural characteristics of the original sample itself,the shear strength is higher than that of the remodeling sample.(2)The vertical pressure remains unchanged,the increase of water content reduces the cohesion force between particles,the friction between soil particles,and the residual strength will decrease with the increase of water content.When the vertical pressure increases,the porosity of soil particles decreases,the contact between particles is tighter,and the peak intensity and residual strength increase significantly.(3)Using the test scheme of "shear-pause-shear-pause-shear",it is found that while the vertical pressure increases,the pore rate increases,the shear strength increases;the recovery rate increases with the pause time and vertical pressure,but the amplitude increases becomes smaller and zero;the cohesion increases with the increase of the pause time.(4)The finite difference software FLAC3 D conducts numerical simulation of the landslide under natural state and saturation state,analyzes the stress,displacement and shear strain increment,and the strength parameters(c,φ)at different pause times can be obtained from the test data,and the safety factor will increase with the pause time,and the slope reaches the final stable state. |
