Reliability Analysis Of Anti-sliding Stability Of Complex Gravity Dam Foundation Based On Improved Response Surface Method

Anti-sliding stability analysis of gravity dam foundation has always been an important content of dam design and safety evaluation.Scientific and reliable analysis results provide effective decision-making basis for engineers and managers.At present,there is no efficient reliability analysis method based on complex dam foundation model in the reliability study of anti-sliding stability of gravity dam foundation.When traditional response surface method is faced with the complex problems of high dimension,high nonlinearity and heavy calculation cost,the fitting accuracy and solving efficiency are not high.Based on the theory of structural reliability and considering the randomness of variables,this paper presents a reliability analysis method for anti-sliding stability of complex gravity dam foundation based on improved response surface method,which combines the stability analysis of dam foundation complex model with the improved response surface method.The main research results are as follows:(1)Aiming at the problems of low training accuracy,slow training speed and many iterations,etc.of traditional response surface method in dealing with small sample,high dimensional and high nonlinear regression problems,firstly,an improved response surface method is proposed: Using extreme learning machine(ELM)to fit implicit performance function,meanwhile,using partial least squares(PLS)to optimize the number and input weights of layer neurons in ELM,which not only improves the fitting accuracy and training speed of response surface model,but also reduces the redundancy of ELM structure as results.Secondly,Dynamic iteration strategy is used to update response surface efficiently and dynamically,which effectively reduces the iteration times and improves the iteration efficiency.(2)In view of the limitation of using plane stress model and finite element model of dam foundation to reflect the complex geological conditions in the past reliability analysis,a reliability analysis method is proposed for anti-sliding stability of complex gravity dam foundation based on improved response surface method.Firstly,according to the geological survey data of gravity dam section,the complex 3D finite element model of gravity dam foundation is constructed.Meanwhile,the performance function value of anti-sliding stability of dam foundation is calculated by using strength reduction fem,and then the improved response surface method proposed in is used to solve the reliability of anti-sliding stability of dam foundation efficiently.(3)The reliability analysis method for anti-sliding stability of complex gravity dam foundation based on improved response surface method is applied to practical engineering.Firstly,the effectiveness and practicability of the proposed method is verified,the distribution structure of sample point is observed,the principal component is studied.Then,the sliding failure process of gravity dam foundation is studied,meanwhile,three instability criterions of dam foundation,which including entirely run-through of plastic zone,displacement of characteristic points and non-convergence calculation,are compared and analyzed.Furthermore,the sensitivity analysis of research variables is carried out based on trained response surface.