Study On Prior Error Evaluation Time Adaptive Method And Application In Seismic Liquefaction Analysis Of Saturated Sand

Seismic liquefaction is a common disaster phenomenon.In order to study the degree and mechanism of seismic liquefaction,dynamic numerical simulation is an effective research way to reproduce and predict the process of seismic liquefaction.However,in order to improve the calculation accuracy,if the time step is set too small in the process of dynamic numerical simulation,the calculation cost is too high.In order to save calculation time,if the time step is set too large,the calculation results will diverge and even the calculation will be interrupted suddenly.In order to improve the computational efficiency,it is difficult to find an appropriate time step to save the computational cost and improve the computational accuracy.In order to solve the above problems,this paper developed a new priori error evaluation time adaptive method,and the main conclusions are as follows:(1)A new priori error evaluation time adaptive method is proposed.Two sets of formulas for calculating the adaptive time step are derived and determined,and the formulas are verified by an example with analytic solutions.The results show that the priori error evaluation time adaptive method can effectively improve the computational efficiency.(2)By studying the correlation between the adaptive time step and the calculation precision and the external load,the rationality of the time adaptive method is analyzed.And the method is valued in four aspects of calculation accuracy,computational efficiency,convergence and stability.The following conclusions are drawn:after time adaptive,the computational efficiency of the original numerical calculation program can be effectively improved while the computational accuracy can be guaranteed,the calculation convergence can be guaranteed at least not lower than the original numerical calculation program,and the computational stability of the original numerical calculation program can be improved to some extent.(3)To solve the problem of how much the computational efficiency of nonlinear dynamic numerical computation program which cannot obtain analytic solution can be improved by using the method proposed in this paper,the solution is proposed and its effectiveness is verified respectively.(4)The application of posteriori error evaluation time adaptive method in numerical calculation of seismic liquefaction is introduced,and its defects is analyzed.On this basis,the time step of the posteriori error evaluation time adaptive method is optimized by using the method presented in this paper,and then it is verified that the method proposed in this paper can effectively improve the efficiency of numerical calculation of seismic liquefaction.Finally,the method proposed in this paper is applied to the numerical simulation of seismic liquefaction finite element,the time step setting problem is solved effectively by a 2-dimensional earth embankment example,and the computational efficiency is significantly improved.