STUDY ON STRESS STATE AND PROTECTION OF EXCAVATED CUTTING OF HIGH SLOPE IN GENTLY INCLINED RED BEDS

More and more rock slope problems are met in highway construction.Because of complex structure of rock body,there are many difficulties in calculating and protecting slope stability.The stresses and deformations of excavated cutting of high slope(height 40,50,60,70,80 m with slope ratio 1∶0.5,1∶0.75,1∶1,1∶ 1.25,1∶1.5) are calculated as the prototype in gently inclined red beds natural slope of an expressway in Sichuan province,adopting the numerical simulation technology of finite element method(FEM).The computed results indicate that shearing stress focus zone moves from slope foot to top slope as slope ratio changes from steep to slow and the surface of deformation-failure of slope will also move in this wayi,.e.,as the excavated slope ratio is greater than 1∶0.75,slope body shearing stress is concentrated near the slope foot;when the excavate slope ratio is lower than 1∶0.75,shearing stress focus zone is not located near the slope foot,but lie in position on the upper side of the middle of slope body.According to this conclusion,a rational protection pattern of rock slope is presented for reference to engineering design.