Reasonable Construction Technology Research On Road Cutting Slope Of Weathering Layers

Slope stability has always been a hot research topic in geotechnical engineeringfield, people often using the safety factor based on limit equilibrium method toevaluate it. Limit equilibrium method is simple and practical, but can not fully reflectslope’s stress and displacement state. While numerical simulation method is a goodway to solve the stability of excavation slope. In this paper, rely on the Ministry ofCommunications Western Project （200631880237）, the reasonable constructiontechnology of weathering layer cut slope is studied based on FLAC^3D. The mainconclusions and results obtained are as follows:（1） The traditional dichotomy is modified by using advance and retreat,combined with the strength reduction method and then the strength reduction of slopestability analysis based on modified dichotomy is proposed.（2） Based on self-made strength reduction method, the road cutting slope ofweathering layers is simulated by using FLAC^3D, with the stress displacement, plasticzone and the velocity vector obtained, which reveals the law of potential slidingsurface changing with excavation ratio and excavation depth. The results show thatslope stability is more sensitive to excavation ratio than excavation depth.（3）Assuming that the best excavation depth with the soil strength and shapeparameters are quadratic polynomial function relationship, the coefficients of thepolynomial is obtained by fitting a large number of calculated dates from the slopesafety factors under various parameters and excavation depths, so the best excavationdepth table is recommend. And the reasonable slope ratio range of homogeneous rockslope is given according to the calculated dates from the shear strength values as theslope safety factor of various parameters and excavation depths equal to1.3.（4） Based on self-made strength reduction method, the process ofthree-dimensional slop excavation is simulated by using FLAC^3D, finding that theslope safety factor and the excavation width is not simply the inverse relationship, butdetermined by the excavation depth. A design process of anchor slope supportingtimely after excavation is proposed, which is simulated to find out the potentialsliding surface after timely anchor supporting will extend to internal slope. Finally,the project example of anchored slop is analyzed by using software of both Li-zhengand FLAC^3Dand the failure reason is summarized. Both calculation results are consistent to verify the accuracy of this numerical simulation.