Slope Stability Analysis Under Earthquake Action Based On Sarma Method And IRMO Algorithm

Cause the instability of slope geological disaster is one of the common engineering practical problems facing the world,and process of slope instability to earthquake hazard is particularly serious,how to evaluate and predict the slope stability under earthquake force,and the critical sliding surface of the slope to the appropriate location search and shape,is under the action of earthquake urgently needs to solve the core problem of slope stability analysis.In this paper,through the analysis of slope instability mechanism in the process of the earthquake by pseudo-static method to simplify the seismic effect,is introduced into the modified Sarma method of limit equilibrium,is deduced based on the improved Sarma method under the seismic action of slope,the safety coefficient expression of the implicit solution as objective function of the radial movement(IRMO)algorithm,The problem of searching the critical slip surface of slope and calculating the corresponding safety factor is transformed into the problem of solving the functional extremum of slide path optimization,and then a slope stability analysis theory based on Sarma method and IRMO algorithm is proposed.The main work and conclusions of this paper are as follows:(1)Using the limit equilibrium Sarma method for calculating the slope safety factor,and to improve the traditional Sarma method,improve the layout of underground water level of the side effects of hydrostatic pressure and under the heterogeneous soil slope more,how shear strength parameters of the lateral changes,etc,to adapt it to the more complex conditions under the condition of slope stability analysis.The iterative solution expression of the horizontal seismic force coefficient Kh containing the safety factor Fs in the improved Sarma method is constructed as the objective function of the subsequent algorithm,in which the seismic force coefficient simulates the seismic effect of the slope in the way of quasi-static method,and the parameter composition of the seismic force coefficient in different engineering specifications is summarized and the applicable scope is limited.The monotonicity and convergence of the Sarma method are strictly verified by mathematics,which overcomes the problems of the traditional Sarma method,such as difficult convergence,complicated calculation process and low accuracy.(2)In this paper,by further improving the data structure of IRMO algorithm and standardizing the mutation probability of the progeny particles,and adjusting the inertia weight that reflects the change trend of the living space of the particle population reasonably,the global and local search effect of the algorithm is improved,and the self-feedback ability of the particles in the algorithm and the probability of selectively preserving the good information of the previous generation particles are increased.In the slope stability analysis under the action of seismic force,the expression of critical non-circular slip surface of seismic slope is formed by the multidimensional vector matrix composed of the starting point of the upper boundary slip surface and the dip Angle between the slip surface and the horizontal plane as variables,and corresponds to the nod dimensional matrix representing the relative positions of the children in the algorithm.By taking the implicit solution expression of safety factor of modified Sarma method under seismic force as the new objective function of the algorithm,the critical slip surface of target slope under seismic force is searched and the safety factor is solved.(3)Based on the combination of Sarma method and IRMO algorithm theory,the analysis program was compiled by Qt creator with computer language logic,and three ACADS computer association test examples were used to verify the feasibility of the improved Sarma method in slope stability analysis.Through four typical examples of slope subjected to seismic forces,the wide applicability of the program in the study of slope stability under seismic forces is verified,and the specific effects of horizontal and vertical seismic coefficients on slope stability properties,safety factors and the development trend of critical sliding surface are analyzed.Finally,it is proved that the program has many advantages in computational efficiency,accuracy and stability according to two engineering examples.(4)The sensitivity analysis of cohesion c,internal friction Angle φ,soil gravity γ and slope Angle β is carried out in the case of slope under the influence of complex seismic effects.The effects of these parameters on the safety factor and the range of critical slip surface are summarized.The corresponding function relations are summarized.It is concluded that cohesion and slope Angle have the greatest effect on slope stability under earthquake action,which provides a train of thought and direction for anti-slip treatment of earthquake slope.96 figures,26 tables and 104 references...