Numerical Simulation Of Progressive Failure Mechanism Of Anchorage Interface In Soft Rock

With the in-depth promotion and implementation of the "the belt and road initiative" plan and the new round of China’s western development strategy,a large number of complex and high-risk construction projects such as large-scale water conservancy projects,high and steep slopes,deep and long buried tunnels,and kilometers of mining mines have emerged in China in recent years.Affected by the project site selection and special geological environment,the above-mentioned projects will inevitably cross the weak stratum.Due to the low quality index of stratum rock and soil and loose structure,the traditional anchoring support members generally have problems such as low anchoring force,poor anchorage,easy interface slippage failure,etc.,which bring severe risk challenges to the project safety construction and even induce project safety accidents.In this paper,aiming at the problem that anchorage support in soft rock stratum is prone to failure and disaster,based on the results of early indoor shear test of anchorage interface,the progressive failure mechanism of anchorage interface in soft rock stratum is revealed by means of theoretical analysis and numerical simulation,which has certain theoretical guiding significance for guiding the design of anchorage support in soft rock stratum and ensuring the safety construction of engineering projects.The main work of this paper includes the following three aspects:1.On the basis of literature research at home and abroad,the structural composition of anchorage interface in soft rock stratum and the rationality of interface mechanical action model are analyzed,the existing mechanical constitutive relation of anchorage interface failure behavior is summarized,and the strength weakening characteristics and progressive failure mechanical characteristics of anchorage interface in soft rock stratum are analyzed.2.Based on the results of early laboratory shear test of anchorage interface in soft rock stratum,in ABAQUS finite element analysis software,the mechanical parameters and constitutive relation of interface unit layer are modified twice by constructing the interaction unit layer of anchorage agent-stratum soft rock interface,considering the elasticity,plasticity and damage evolution characteristics of interface unit layer,which reproduces the laboratory shear test process and mechanical evolution characteristics,and realizes the effective simulation of gradual failure process of anchorage interface in soft rock stratum.3.Based on the revised numerical simulation method of gradual failure process of anchorage interface in soft rock stratum,considering different anchorage length,borehole diameter,interfacial bond strength,elastic modulus of soft rock and other factors,a series of comparison schemes are designed,and the numerical simulation comparative study of gradual failure process of anchorage body in soft rock stratum is carried out,which reveals the influence law of different working conditions on stress distribution and ultimate bearing capacity of anchorage body,establishes the sensitivity evaluation index of influencing factors of anchorage body bearing capacity,analyzes the influence sensitivity of different factors,and gives corresponding engineering suggestions and measures.