Research On Failure Mechanism Of Ranistorm-lnduced High Cutting Slope And Supporting Countermeasure

With the rapid development of China’s expressway, the stability of high cuttingslope in expressway received extensive attention.There are a lot of high cuttingslopes along the expressway in Guizhou province.It developes lots of structuralsurface, rock is broken in high cutting slope,which are not advantageous to thestability of the slope. In this paper,there are a lot of structural surface in the highcutting slate slope, slate on the surface weathered seriously and the foot of slope is infault fracture zone after excavation.Theoretical analysis and numerical analysis areused to analyse the deformation and failure mechanisms including during excavation,considering rainfall after supporting.Numerical analysis and stability evaluation areused to analyse the seepage considering rainfall, having a study on treatmentscheme.There are the following results:1.According to the phenomenon in the Field survey and excavation process,fundamental factor leading to deformation and destruction is artificial excavationwhile inducing factor is rainfall.2.According to the shape of slope, rock structure, factors leading to deformationand destruction, it appears creep-crack form.3.Numerical analysis is used to simulate the deformation of slope by FLAC3D,itappears that there is steep free face during the first stage of slope excavation,second and sixth grade slope appeared partially destroyed, shear failure zone does notconnect, potential sliding surface is not formed.After completion of the excavationand support, near the edge of the stairs and the second stage it appears the maximumprincipal stress concentration,potential sliding surface is formed.4.According to the result of seepage study, it appears that with the increase inrainfall time, pore pressure increases, slope stability decreases. When the rainreaches42hours, slope stays limit equilibrium state, slope needs for reinforcementin this case.5.According to the first anti-slide pile calculation, deformation of the slope,location of the most dangerous sliding surface and so on, prestressed anchor cable should be choosed to reinforce the slope.