| The heavy rainfall brought by typhoons often induces landslides and other geological disasters.As there are few plains and low hills in Fujian province,power transmission and transformation projects have to be built on steep terrain such as mountains.The slope rock and soil mass in these areas are prone to landslide and other geological disasters induced by rainfall,resulting in tower foundation failure and power tower overturning,and serious transmission line tower collapse.Therefore,it is of great engineering significance to study the stability of power transmission line foundation slope for ensuring line stability and power channel security.This paper qualitatively analyzes the causes of slope instability induced by typhoon in Fujian province through systematic collection and collation of data in the study area.Combined with field research on soil and water conservation measures of each power transmission and transformation project foundation slope,typical cases are selected for numerical simulation research.Finite difference software is used to simulate the stability of the foundation slope under different working conditions and analyze the conclusions.According to the conclusions,corresponding comprehensive treatment measures are proposed for the foundation slope,the specific contents are as follows:(1)Through field investigation,the soil and water conservation measures of power transmission and transformation project in this region are collected and analyzed,and various factors of soil erosion and geological disasters of power transmission and transformation project are analyzed and evaluated.By referring to relevant data and literature,the coupling instability mechanism between strong typhoon and geological structure,landform,formation lithology and rainfall was studied,and the slope instability caused by strong typhoon was qualitatively analyzed.Combined with the survey results of the foundation slope of power transmission and transformation projects in various cities,the stability of the foundation slope of Yidu Substation in Yongchun under the action of strong typhoon is emphatically analyzed.(2)The "Rhino-Griddle-FLAC3D" numerical modeling method was used to construct a three-dimensional numerical model for stability analysis of the foundation slope.Flac-3d software was used to conduct numerical calculation for the foundation slope under four working conditions(dead weight,gale,rainstorm and typhoon rainstorm).The displacement cloud map,shear strain increment cloud map and safety factor Fs(1.285,1.280,1.027,1.023)were obtained under four working conditions.The stability results of the foundation slope were obtained through comprehensive analysis,that is,the foundation slope was basically stable under the working conditions of dead weight and strong wind,and under the working conditions of rainstorm and typhoon.(3)The main deformation area of the foundation slope is monitored and the failure range and failure mode under the limit state are analyzed by strength reduction method.The possible sliding surface is located in the top surface of the slope 7m from the slope surface.The shear failure sequence of slope under dead weight condition is: slope surface→slope foot→slope shoulder.The shear failure sequence of slope under gale condition,rainstorm condition and typhoon rainstorm condition is: slope foot→slope surface→slope shoulder.(4)According to the basic characteristics and stability analysis results of the foundation slope of Yidu 110 KV power transmission project in Yongchun,Fujian province.It is put forward that the slope is treated comprehensively by adopting the engineering measures such as rock bolt frame grid planting grass slope protection,slope top hardening combined with intercept ditch drainage and slope foot drainage. |
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