Study On Influence Of Excavation Effect On Stability Of Stepped Slope

With the development of human productive activities, more and more excavationslope engineering arise, the phenomenon of slope failure is increasingly frequent duringthe construction process and cause huge losses. But for stepped excavation slope, thestudy on influence of excavation effect is still not perfect and there in no clear andreasonable theory basises for engineering design. This paper has carried out the researchon influence of excavation effect on stability of stepped slope, and it provides referencefor the economic and reasonable slope design and evaluation of slope stability inengineering application, it is of immediate significance.This paper takes the second-order and third-order homogeneous stepped excavationslope, and the second-order anisotropic stepped excavation slope of upper-strong andlower-weak, as well as the slope of upper-weak and lower-strong as the research object. Ithas carried on the thorough analysis and research on safety factor and potential slidesurface of slope under the condition of different control parameters by considering theexcavation effect or not. After the thorough comparison research, a suggestion forstability calculation method and optimized design of stepped excavation slope ispresented.The main conclusions of the thesis are as following:(1) For stepped excavation slope, the excavation effect will bring down the safetyfactor of the slope, but the safety factor of the overall slope has been less affected byexcavation effect; for the potential slide surface of the overall slope, homogeneousstepped excavation slope and anisotropic stepped excavation slope of upper-strong andlower-weak has been less affected by excavation effect, but for anisotropic steppedexcavation slope of upper-weak and lower-strong, the potential slide surface is greatlyaffected by excavation effect, and will make it be shallow obviously in the middle andlower part.(2) For homogeneous stepped excavation slope and anisotropic stepped excavation slope of upper-strong and lower-weak, the traditional limit equilibrium method can bedirectly used to do the research on stability of the slope, and according to the location ofpotential slide surface of the overall slope for reinforcement can ensure the safety of theslope. But for anisotropic stepped excavation slope of upper-weak and lower-strong, theinfluence of excavation effect should be considered, and it is needed to do research onstability of the high slope, in order to ensure the safety of the overall slope and therationality of the reinforcement design.(3) The platform width of stepped excavation slope should not be less than0.5timesof the average height of the adjacent two-stage slope.(4) For homogeneous stepped excavation slope and anisotropic stepped excavationslope of upper-strong and lower-weak, the slope height ratio of the adjacent two-stageslope should be controlled in the range of1~2. But for anisotropic stepped excavationslope of upper-weak and lower-strong, the slope height ratio of the adjacent two-stageslope should be controlled in the range of0.6~1.(5) From the angle of the stepped slope rate, for different homogeneous steppedexcavation slope, when the maximal slope ratio of the local slope is certain, then from topto bottom along the slope, the slope rate of each grade slope decrease by turn will bemore conductive to the overall stability of the slope. For the anisotropic steppedexcavation slope of upper-strong and lower-weak, as well as the slope of upper-weak andlower-strong, properly reduce the slope rate of the grade slope with weak materials willbe more conductive to the overall stability of the slope.