Numerical Simulation Study on the Mechanism of Rainfall Induced Disaster of Excavation Soil Slope in a Certain Highway
This paper takes a rainfall-induced landslide disaster in a certain highway engineering area in the upper reaches of the Dadu River as a case study.Based on detailed post-disaster investigation,the original topography of the slope is restored.Numerical simulation technology is employed to simulate the seepage field and stability of the excavated slope,elucidating the disaster mechanism of the landslide under heavy rainfall conditions.The study shows that the landslide is a small-scale cohesive soil landslide,sliding along the interface of the base covering and shearing out along the excavation face.Under the influence of heavy rainfall,significant changes occur in the original slope seepage field,with transient saturation zones forming locally on the slope surface.Gravity-induced pore water converges towards the slope toe,leading to the formation of saturated zones at the foot of the excavation.Additionally,the stagnant water belt near the base-covering interface contributes to the creep deformation of the slope.With the continuous impact of heavy rainfall,the broken stone soil transitions from unsaturated to saturated state.The lubrication and softening effects of pore water lead to mechanical strength degradation,combined with the lack of the anti-slide segment after excavation,ultimately resulting in instability and failure of the slope under self-weight.Such rainfall-induced landslides are common in engineering construction.Failure to address or improper disposal after excavation may create conditions conducive to disaster.The study of this case provides reference for similar engineering projects.
Excavated slopeBlock gravel soilHeavy rainfallNumerical simulationSeepage field