Damage mechanism of roadway surrounding rock under coupling of high pre-stress and gas explosion

In recent years,China's coal mine safety has been improved to some extent,but the gas explosion accident has not been fundamentally eliminated,and it is still the top priority of coal mine accidents. The gas explosion in the deep roadway of coal mine caused huge accident damage. The explosion impact not only caused casualties,but also caused roadway collapse,mainly because of the coupling effect of high pre-stress and explosive loading. In order to study the high pre-stressed damage and gas explosion loading under the action of coupling damage law of roadway sur-rounding rock and the mechanism of action of several kinds of superposition of loading,based on the numerical simulation software ANSYS/LS-DYNA,the implicit/explicit coupling analysis method was used,and the 0,5,10 and 15 MPa initial in-situ stress and the dynamic response of the roadway surrounding rock under the action of explosion loading coupling characteristics were simulated,through the study of change and displacement of pre-stressed damage and pre-stressed and coupling damage under explosion loading,the change of displacement and stress,it is concluded that the following results:In the absence of in-situ stress,the roadway has almost no pre-stress damage and initial displacement. With the increase of in-situ stress,the extent and area of pre-stress damage and initial displacement of the roadway gradually increase. The roadway has almost no displacement and little damage under the action of explosion loading alone. Under the coupling of the damage caused by the explosive loading and the pre-stress,the roadway displacement and the damage stress increase. Under the coupling action of in-situ stress and explosive loading,the propagation of stress generated by explosion is inhibited in roadway,and the inhibition effect becomes more obvious with the increase of ground stress. There are two functions of in-situ stress:before the action of explosion loading,in-situ stress causes the pre-stressed damage of surrounding rock of roadway,reduces the strength of rock,and leads to deformation and failure of surrounding rock under the action of explosion loading. When the gas explosion loading is applied to the surrounding rock,the in-situ stress inhibits the propagation of stress in the surrounding rock.