Application Of Improved Finite Element Upper Bound Analysis In Slope Stability Analysis

Geological disasters caused by slope instability have a great impact on China's construction,water conservancy,road and bridge projects.The development of efficient and accurate slope stability evaluation methods is the research focus of researchers.Based on the traditional finite element upper bound analysis method,this paper introduces the improved Zoutendijk algorithm to calculate the upper bound programming model,and uses the double strength reduction coefficient to replace the equal coefficient reduction to improve it.It proves the feasibility of the method and affects the slope stability.The main factors were studied.Based on reasonable assumptions,this paper establishes a finite element upper bound programming model for two typical engineering examples by numerical discrete technique,and introduces the improved Zoutendijk algorithm and double strength reduction coefficient for iterative calculation.It is found that the algorithm is effective compared with the software built-in optimization algorithm.The calculation efficiency is improved.The accuracy of the calculation results is proved by the finite element strength reduction method and the limit equilibrium method.The double strength reduction factor can further improve the accuracy of the results based on the equal coefficient reduction.The final node velocity field and software simulation are obtained.The slope instability form fits well,indicating that the finite element upper bound analysis method with improved Zoutendijk algorithm and double strength reduction factor is feasible.For the internal factors affecting the stability of the slope,the classical slope example is calculated by the improved method and software simulation proposed in this paper.The maximum horizontal displacement increment,the reduction ratio of the reduction factor and the stability coefficient are plotted.The larger the calculation range is.The more accurate;the change of internal friction angle and cohesion force is linearly related to the slope stability coefficient.Under the double strength reduction factor,the cohesion force has greater influence on the slope stability than the internal friction angle;under certain preconditions,the elastic modulus And the effect of Poisson's ratio is negligible.The numerical results of the improved method proposed in this paper are better,and the overall results are slightly smaller than the software simulation results,which is consistent with the upper bound solution.In view of the role of external water,this paper mainly studies the working conditions of water level drop in the reservoir area,introduces the delay height and nonlinearly fits its formula,corrects the traditional Boussinesq equation,and derives the expression of hydrostatic pressure outside the slope and pore water pressure in the slope.Taking the bank slope of the spillway project as an example,an upper bound planning model is established,and the improved Zoutendijk algorithm and the double strength reduction factor are introduced for calculation.Select different reservoir water deceleration,permeability coefficient,water supply and average aquifer thickness,using traditional immersion line calculation formula and software simulation as a comparison: reduce water supply;reduce reservoir water deceleration;increase permeability coefficient;increase aquifer The thickness can increase the slope stability coefficient,and the result of considering the delay height is more accurate than the traditional immersion line result,and the software simulation fits well,which is in line with reality.