Instability Mechanism and Engineering Effect Evaluation on Gently Tipping Deposit Landslide Under Rainfall
There are few targeted studies based on the landslide disaster mechanism mode and landslide control engineering countermeasure model.This article takes an expressway landslide in Northwestern Yunnan as the object.The combination of macroscopic evidence investigation,landslide stability evaluation,sliding zone strength index reverse calculation,and numerical analysis calculation was adopted to systematically study the entire process of landslide induced by cutting slope excavation.The disaster mechanism of slope landslide was analyzed,and the effectiveness of its remediation engineering was evaluated.The result indicates that due to the influence of excavation and unloading during the road cutting slope construction,the stress field of slope body is adjusted.The stress relaxation occurs at the interface between the shallow surface layer in slope upper part and the soil rock interface at roadbed lower part.The stress concentration occurs locally at the slope foot,gradually expanding to form the plastic zone,ultimately forming the potential sliding surface that connects the relaxation zone in the shallow surface layer and the soil rock interface.Affected by sustained heavy rainfall,the surface water infiltrates the slope,increasing the soil moisture content and softening the rock and soil at the soil rock interface,resulting in a decrease in strength.The shallow surface stress relaxation zone of slope and the potential sliding surfaces undergo yield deformation,continuously developing upwards and downwards until they are connected,leading to cutting slope sliding.The landslide control engineering adopts comprehensive measures,e.g.,multi-level brushing and unloading,anchor frame beams,anchor anti slip piles,and interception and drainage ditches.After the rectification engineering implementation,the slope is in a stable state,meeting the regulatory requirements and achieving good results.The evolution and remediation of landslide disease have gone through the main engineering stages of initiation,excavation,deformation and failure,and engineering remediation.Comparing the stability calculation result of each stage with the macroscopic evidence investigation result,the stability calculation result is consistent with the deformation and remediation effect of landslide in each stage.
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