Study On Slope Stability Analysis Based On Double Strength Reduction Method

The finite element strength reduction method has many advantages in analyzing the slope stability:it does not have to make too many assumptions about the slope,and it is suitable for the slip surface of arbitrary shape,and can adapt to the slope stability analysis of various complicated working conditions.However,the strength reduction method is based on computer software and belongs to a numerical analysis method.Its results are affected by many factors.Therefore,it is very necessary to summarize and explore the main influencing factors.When the traditional strength reduction method is used to solve the safety factor of slope,the reduction of the shear strength parameters c and ? is performed in equal proportion and synchronously,that is,the same reduction factor is adopted;however,a large number of experimental studies have shown that the shear strength parameters are affected by external factors.The degradation law of c and ? are not the same,wherein the value of ? is relatively stable,and the fluctuation of c value is large.Therefore,reducing the shear strength parameters c and ? according to the same reduction factor does not conform to the deterioration law of the slope strength parameter.From the perspective of the mechanism of slope failure,different reduction factors should be used to reflect the reduction of strength parameters,and the relationship between the two reduction factors should reflect the deterioration law of the strength parameters.The safety factor thus obtained is more accurate.Based on the ABAQUS software,this paper studies the theory and implementation method of the strength double reduction coefficient method,and mainly does the following work:(1)The parameters of the published unsaturated soil direct shear test and triaxial shear test are fitted,and the relationship between the soil strength parameters and the water content is established.The supporting reduction mechanism of the strength parameters is derived:F?=Fck.A new comprehensive safety factor definition method is also proposed:Fs=(?).(2)Contrast the value of the safety factor determined by the three criteria of slope instability in the strength double reduction coefficient method.The results show that in the process of analyzing slope stability,the results of calculating the non-convergence criterion often deviate greatly,it is reasonable to consider the safety factor value of the plastic zone penetration criterion and the characteristic point displacement abrupt criterion.The influence of the elastic modulus E of the geotechnical material,Poisson's ratio v,soil weight ?,internal friction angle ? and cohesion c on the safety factor of the slope is also explored.(3)Combining the M-P method and the strength reduction theory,the generalized limit equilibrium-double reduction coefficient method is proposed,and the stability of several homogeneous soil slopes is analyzed by this method.The results are consistent with the finite element strength double reduction coefficient method.The correctness of the finite element strength double reduction coefficient method is demonstrated.(4)Using the finite element strength double reduction coefficient method,the safety factors of three typical complex slopes are calculated,and compared with the limit equilibrium method and the traditional finite element strength reduction method.The results show that the limit equilibrium method and the traditional finite element strength reduction method both overestimate the safety factor of complex slopes.(5)Finally,the stability of the slope strengthened by anti-slide piles is studied by the strength double reduction factor method.The three-dimensional numerical analysis of the anti-slide pile layout position Lx/XL,the anti-slide pile spacing D/d and the anti-slide pile body are explored.The double reduction coefficient method proposed in this paper has a clear theoretical basis and practical significance.It can provide a way of thinking for the stability analysis of soil slope.Engineers can use the results of this method as a basis for slope stability evaluation.