The Research On Stochastic Mechanical Characteristics Of Ultra-deep Anti-slide Pile In Three Gorges Reservoir Region

Landslides happen frequently and on a large scale in our country. Thus, it has become a research focus to manage landslides in the field of geotechnical engineering. Now, anti-slide pile provides an effective way for the management of landslides. In fact, there are many uncertain factors in geotechnical engineering. While method of definite value without considering the randomness of rock, the results will tend to safe. Research stability of landslide and anti-slide pile structure from the perspective of built-in reliability and pay attention to the random factors that affect their safety, which not only reveal both scientificity and rationality of this reinforcement measures, also give reference about reliability between the ground part and underground part.Research in four aspects of this paper as follows:⑴Read and study relevant literatures, then summarize the development overview of current geotechnical engineering in the field of reliability, the application research on anti-slide pile in terms of reinforcing the slope, and the progress of anti-slide Reliability. Finally analyze the application progress in the aspect of reinforcing the large-scale landslides.⑵Make brief instruction about basic concepts, such as built-in reliability, probability of failure, and reliability index. Analyze and study the methods which calculate the degree of reliability. Then summarize the usable range, advantages and disadvantages of each method. At the same time,this paper choose the appropriate method to analyze the reliability of anti-slide pile structure combined with anti-slide pile structural reliability analysis of characteristics.⑶Consult the landslide engineering project in Three Gorges Reservoir Region and combine with the characteristics of geotechnical engineering and project, this paper select soil bulk density, cohesive strength, the angle of internal friction, length of anti-slide pile,cross-sectional area and the elastic modulus as the random input variables, on this base, figure out the structural performance function of anti-slide pile; and then apply PDS block in ANSYS software to analyze reliability of anti-slide pile, use Latin Hypercube Sampling in Monte Carlo Method to analyze the maximum displacement, maximum bending moment, and maximum shear force; use of the structural performance function has been built to obtain probability of failure of the displacement, bending moment, shear force are 0. 7%, 0. 87% and 0. 84%. this paper described the method to calculate the reliability of anti-slide pile is feasible by comparing the reliability index in existing literature with the papers results. This paper also regard the simulated results from Monte Carlo Method as exact solution and compare the feasibility of Response Surface Method, as a result, Response Surface Method can assess the probability of failure of the pile well.⑷Detailedly introduce the fundamental principle of sensitivity analysis and apply the spearman rank correlation coefficient method in sensitivity analyses to analyze the displacement, bending moment, and shear force sensitivity of anti-slide pile. it can conclude that pile length, the angle of internal friction in slide-body, cohesive strength of sliding zones soil all have important influence on reliability of structure.