| In the mountainous areas of southwest China,there are more reverse-slope high slopes due to the complex topography,geomorphology and geological conditions.It has been found for many years that the anticlinal slopes are often damaged by tipping,which causes great danger to human life and engineering safety.In view of this,this thesis is based on finite unit method,indoor physical test and limit equilibrium method to study the typical reservoir bank anteversion sandstone slope.The main research work and resultsare as follows.(1)Geo-Studio analysis software was used to obtain the law of stress change in the slope during the rise and fall of reservoir water level.During the rise and fall of the water level,the effective stress of the slope changes significantly at the interface between the leading edge of the slope and the rock-soil intersection.After the reservoir water level is stabilized,the stress field in the slope is still changing and finally stabilizes.During the water level rise and fall,the slope displacement traces change with the water level.As the slope angle increases,the maximum displacement position rises along the slope surface,and the sandstone displacement is smaller than the mudstone displacement after the displacement becomes stable.Analyzing the influence of different layer thickness ratios on the slope displacement,we can get that the slope displacement is smaller for the layer thickness ratio of 0.5 and 2,and the displacement is larger for the layer thickness ratio of 1 and 1.5.(2)The damage law of the reverse slope under the water level change condition was studied by the physical test of the reverse slope under the indoor water level change condition.The results show that the overlying soil pressure increases slowly due to the infiltration of water into the soil,and the soil pressure value firstly shows a rising trend.After that,the soil pressure measured at the measuring point gradually decreases because the floating support effect caused by the rising water level reduces the soil selfweight effect.Under the action of upper uniform load,the smaller the dip angle is,the higher the rock pressure is.After the damage of the rock layer,the pressure on the rock layer decreases slowly and forms a continuous damage surface.(3)Based on the cantilever beam theory of the reverse inclined slope,the formula for calculating the underthrust force and stability coefficient of each rock layer of the reverse inclined sandy mudstone interlayer slope and the calculation method for the overall stability of the slope are proposed under the condition of reservoir water level change.The stability coefficients of each rock layer and slope stability coefficients under different working conditions are analyzed and obtained.Combining with engineering calculation examples,the stability analysis law of slope of reverse inclined sandstone interlayer is obtained.The results show that due to the difference of force conditions and other factors between different rock layers,the slope as a whole shows the damage form of top tipping and bottom sliding.In order to verify the rationality of the theoretical formula,a two-dimensional model of the slope considering the water level change was established by using numerical software.Based on the limit equilibrium method,the change characteristics of the slope stability under different influencing factors were analyzed,and the change law of the seepage field and stability coefficient of the slope under the condition of water level rise and fall was derived.(4)Single-factor analysis and multi-factor orthogonal analysis are used to analyze the slope slope angle,rock layer inclination,rock layer thickness ratio and water level rise and fall rate sensitivity of slope stability factors respectively,and compare the two methods to verify the reasonableness of the results and to distinguish and rank the primary and secondary relationships of the factors influencing the stability of reverse slope according to the calculation results. |
PDF Full Text Request