Stability Analysis Of Composite Soil Nailing Support Structure And Sensitivity Analysis Of Its Influencing Factors

The stability analysis of composite soil nailing structures is mostly based on soil nailing walls,stability analysis commonly used the limit equilibrium method in engineering practice and research.Because the slip surface is affected by factors such as soil parameters and the shape of the pit,how to determine the position of the slip surface becomes a difficult point in the stability analysis by the limit equilibrium method.When analyzing the influence of various factors on the stability of the support structure,the most common method is to assume that a certain factor changes within a reasonable area and the remaining factors remain unchanged,and then judge according to the magnitude of change of the drawn curve.However,this method can only analyze the trend of the impact of various factors on the stability index,and can not judge the influence level of each factor to stability.In view of the above problems,this paper mainly analyzes the sensitivity of factors that affect the stability and stability of the composite soil nailing structure on the basis of existing studies.The specific content is as follows:?1?Firstly,this article starts with the structural composition of the anchor-soil nailing compound support structure to explain the mechanism of the reinforcement of the composite structure and analyze the reason for the change of soil parameters during the consolidation process.Secondly,based on the failure modes of soil nails and the characteristics of anchor-soil nailing compound support structures to analyze the failure modes of composite soil nail structures.Based on the existing studies,the commonly used sliding surface forms in the analysis of support structure stability were summarized.Finally,summarizing the existing methods for analyzing the stability of support structures and the search methods for sliding surfaces,and elaborating the principles,advantages and disadvantages of various methods,which provides theoretical support for the study of this paper.?2?This paper assume that the sliding surface of the composite soil nailing support is parabolic.Learning from the thought of traditional segmentation method,using the integral method to analyze the internal stability of the anchor-soil nailing compound support structure,and then calculating the stability coefficient by the ratio of the anti-sliding force and the sliding force at the sliding surface.On this basis,deducing the functional relationship between the position coordinates of the slipping point on the slip plane and the stability coefficient,and then using the genetic algorithm in MATLAB to perform a dynamic search within the possible area of the slipping out point.Obtaining the minimum stability coefficient and the position coordinates of the slip point of the corresponding slip surface.Finally,the calculation method deduced in this paper is used to analyze the stability of a certain foundation pit project,and its rationality is verified from the calculation results of Lizheng Deep Foundation Pit 7.0 and FLAC^3D.?3?According to the appropriate criteria to select reasonably the factors and levels.On the basis of the orthogonal experiment test,using the stability analysis model established in this paper,and then choosing the stability coefficient and the slip surface position as the response indicators of the stability of the anchor-soil nailing compound support structure.From the uncontrollable factors and the controllable factors to analyze the sensitivity of the influence factors of the stability of the support structure and explore the primary and secondary relationships between the influence of various factors on the stability of the composite soil nailing structure.