Research On Reliability Of Bolt-supported Roadway Based On Response Surface Method

With the increase of mining depth,the in-situ stress gradually increases,the mining difficulty of the roadway increases,and the stability of the roadway decreases.Especially in the condition of large cross-section and weak rock formation,the roadway is prone to safety accidents such as roof fall and gangway,which seriously endanger the underground staff and life safety,affecting the normal production and operation of the coal mine underground system.Therefore,solving the problems of roof fall and gangway in roadway is the key link to ensure the safety and efficient mining of underground coal resources.In this paper,relying on the National Natural Science Foundation of China（52074116,51804113,52004088）,based on the failure mode of the roadway under the bolt support,the limit analysis upper limit method,the response surface method,the numerical simulation and the field monitoring method are combined to investigate the stability of the large-section soft rock roadway,which can provide a reference for the supporting design of similar roadways in the future.The main work done in this paper is as follows:（1）Based on the plastic limit analysis and Platts theory,considering the influence of in-situ stress,the failure mode and velocity field of the large-section soft rock roadway under the condition of bolt support are constructed,and the rationality of the failure mode is verified by FLAC^3Dnumerical simulation.（2）Introduce the nonlinear Hoek-Brown strength criterion to characterize rock mass characteristics,and use the upper limit method of limit analysis to deduce the external power and internal energy dissipation rate such as gravity,ground stress,bolt support force,etc.in the failure of large-section soft rock roadway.The energy dissipation conservation equation is established,and the optimal upper limit solution of the support force of a single bolt is solved by the sequential quadratic programming algorithm（SQP）in MATLAB software.（3）According to the reliability theory,the reliability model of the large-section soft rock roadway under bolt support is established,and the response surface method is used to solve the failure probability and reliability index of the large-section soft rock roadway to obtain a reasonable support force range.（4）Taking the transport roadway of the Mine as the engineering background,limit analysis theory and response surface method are used to solve the optimal upper limit solution of supporting parameters such as bolt spacing and inclination angle,and three support schemes for roadway surrounding rock are proposed.FLAC^3Dfinite difference software was used to simulate the three support schemes,and the rationality and superiority of the optimal solution were obtained by combining on-site monitoring to verify the theoretical method.