Upper Bound Analysis Of Surrounding Rock Pressure In Deep Roadway Under Nonlinear Failure Criterion

With the gradual depletion of the shallow coal resources,the coal mining depth has gradually stepped into the kilometer level deep area.However,the complex stress environment of the deep surrounding rock,the increase of the structural stress,the increase of the plasticity of the rock mass,the high temperature,the high ground stress,the complex geological conditions and other factors often lead to the roof collapse,the sheet side,the floor heave and other catastrophes.It does harm to the service life and the service life of the roadway.This kind of disaster can be effectively solved by accurately knowing the surrounding rock pressure of deep roadway according to the surrounding rock pressure.In order to accurately solve the problem of surrounding rock pressure in deep roadway,the failure mode of"wedge collapse+rotating circular arc"is constructed based on the non-linear Mohr-Coulomb and Hoek-Brown failure criterion.The expression of the upper bound solution of surrounding rock pressure is deduced in deep roadway according to the virtual power principle of limit analysis.And the failure mode is verified.Under the nonlinear failure criterion,the influence of each parameter on the upper bound solution of the surrounding rock pressure is analyzed.Finally,the reliability of the limit analysis method is verified by numerical simulation and engineering examples.The main work and conclusions are as follows:（1）The failure mode of"wedge collapse body+rotating circular arc body"is established,and the expression of surrounding rock pressure under the ultimate failure state of deep roadway is deduced.（2）The reliability and superiority of the failure mode constructed in this paper are verified by comparative analysis.（3）The influence of rock mass parameters and failure criterion parameters on the surrounding rock pressure of deep roadway is analyzed.The results show that under the nonlinear Mohr Coulomb failure criterion,the surrounding rock pressure decreases with the increase of lateral pressure coefficient and internal friction angle,but increases with the increase of nonlinear coefficient m.Under the nonlinear Hoek Brown failure criterion,when the geological strength index GSI,rock mass constant _im and uniaxial compressive strength?_ci decrease,the surrounding rock pressure increases and the effect is obvious;with the increase of disturbance factor D,the surrounding rock pressure increases significantly.（4）The reliability and rationality of this method are verified by numerical simulation and engineering examples.Both numerical simulation and engineering examples show that the failure mode of deep roadway constructed in this paper is reasonable and reliable.