Stress Analysis Of Shaft Inclined Hole And Evaluation Method Of Roadbed Soil Hole Stability

The collapse of karst soil caves is extremely common in the karst areas of southwest China,and has become a major hidden danger in linear engineering construction represented by traffic road engineering in China's karst areas.At present,a series of achievements have been made in the study of the stability of underlying cavities in karst areas,but most of them are studies on karst caves.There are not many studies on soil caves,and from the analysis of the stability of soil caves,The shape of the soil hole in the stratum is assumed to be the shape of a horizontal horizontal earth cave or a vertical vertical earth cave,and the influence of the inclination angle of the soil shaft axis is not considered.Therefore,this paper takes the inclined soil hole of the lower axis of the embankment as the object,and establishes a similar model to carry out a large number of theoretical and numerical analysis studies,in order to make positive contributions to the stability of the soil cave in the karst area.This paper mainly studies the stability of shaft inclined soil cave from the following aspects:Since the stress solution of the soil layer around the soil cave is a key step to evaluate the stability of the soil cave,the paper firstly uses the complex variable function method to solve the hole problem.The core idea is to map the plane of the hole to the unit through the mapping function.The circular outer domain is solved by the power series solution of the complex variable function or the Cauchy integral solution method and the boundary stress of the hole according to the boundary conditions.Then based on the above principle,the stress solutions of the inclined elliptical soil hole and the square soil hole of the lower axis of the embankment are obtained respectively.The method can provide reference for solving similar hole stress problems.Secondly,based on the calculated solution of the soil hole edge stress,combined with the Mohr-Coulomb strength failure criterion,the key points on the soil hole boundary are checked to determine whether the soil hole will be destroyed,and then the stability of the soil cavity is evaluated.The stability factor is introduced to analyze the sensitivity of the main factors affecting the stability of the soil cavity,and the influence of the inclination angle of the soil cavity on the stability of the soil cavity is analyzed.Then,considering the importance of uneven settlement of embankment and ultimate bearing capacity of roadbed for road engineering,based on ABAQUS finite element numerical analysis and analysis software,a large number of numerical calculations are used to calculate the Poisson's ratio,soil hole size and soil cavern.The effects of deep and earthen shaft inclination angles on the settlement deformation of the embankment and the ultimate bearing capacity of the subgrade are discussed in depth.In order to analyze the influence of the inclination angle of the soil hole more clearly and intuitively,the ultimate failure mode of the soil hole under different inclination angles is also analyzed.Finally,through the two engineering examples,the effects of the stability and inclination angle of the slope of the embankment on the settlement deformation of the embankment are compared and analyzed,which shows that the method has certain rationality and feasibility.