Applicability Analysis Of The Model Of Rotate Around The Basis Of Rigid Retaining Wall Support Expansive Soil Slope

In the slope project of expansive soils, although reinforcement measures including soil nailing wall,gravity retaining wall and anti-slide pile and major protective measures including full closed short bolt shotcrete and mortar flag stone for expansive soil slope reinforcement and protection were used by the departments at home and abroad including railway,highway and water conservancy, the failure phenomena of rigid protection in practical project.For investigating the expansive soil slope supported by rigid retaining walls, according to movement modes of expansive soil retaining walls rotated basement, the paper analyzed as follows:Firstly, the samples correlated mechanical properties were determined by the consolidated quick shear test,expansive force test and consolidation test the Bai-se expansive soil of the Bai-se expansive soil. And then, the variation relationships of the expansive force with initial water content and expansive deformation were established to the derivation of earth pressure formulas and numerical analysis.Secondly, the mathematical expression of the variation relationship between the expansive force and depth of soil layer in the climate influenced layer was proposed by summarizing the result of the laboratory test and existing research results. Then, the mathematical expression was introduced to deduce the calculation formula of the soil pressure of expansive soil retaining walls in the rigid retaining walls horizontal layer analysis method, the calculation program of Matlab was compiled to analyze the value of earth pressure,height of earth pressure acted point and the variation of wall displacement resulting from the expansive soil after moistening. According to the stability requirements of the retaining wall, the wall body section size under the expansive force in the different of wall displacement was reverse calculated, and the quantitative indexes of applicability analysis of expansive soil retaining walls were obtained by comparing with wall body section size without expansive force. The test results are showed that the earth pressure acted point rose markedly with the earth pressure increasing after expansive soils water content was less humidifying. When the expansive soil retaining walls was stationary, the wall body section size were needed to increase 2.6 times for the retaining walls stability, and only the deflection on the top of wall reaching 15cm the expansive action would be completely dissipated.Thirdiy, according to the material temperature field equivalent simulated the soil humidity field of FLAC, and the expansive soil humidifying conditions in the climate influenced layer was considered, the interaction between the soil and the retaining wall was comparative analysis. the numerical simulation results are showed the earth pressure rose markedly in the climate influenced layer after moistening, and the remarkable lateral displacement was produced between the retaining walls and the soils behind retaining wall. Considering the security and the project costiy, the rigid retaining wall is unsuitable to support the expansive soil slope.Finally, the advantages and disadvantages of expansive soil slope treatment program such as flexible supporting and rigid and rigid-flexible support were analyzed by gray theory, In considering the project cost, difficulty of construction and ecological protection, compared the flexible support is the best way of treating expansive soil slope, rigid support is the worst.