The Research On The Interaction Between The Deep Surrounding Rock And The Supporting Structure Based On Characteristic Curve Method

As the intensity of coal mining increases,shallow coal resources are gradually depleted,and the depth of coal mining continues to increase.On the one hand,the deep rock mass is in a complex geomechanical environment of "three highs and one disturbance",showing obvious post-peak strain softening and large deformation characteristics of expansion,which is an important reason for the large deformation and failure of deep roadways.Study the deep rock mass after the peak,the deterioration law of strength and deformation parameters is of great significance to the stability control of the surrounding rock of the roadway;on the other hand,the numerical simulation method is an important means to carry out the research of the roadway anchoring mechanism and the optimization design of the support parameters.The Cable unit in FLAC3D is often used to simulate the bolt(Cable)supporting function,but its Cable unit does not have the breaking failure attribute,which expands the control effect of the bolt(cable)on the surrounding rock,which is inconsistent with the actual force state of the bolt(cable),resulting in the existence of bolts(cables)in the roadway.Safety hazards after the support fails.In response to the above problems,this paper takes the interaction mechanism between the surrounding rock and support of the deep roadway as the research object,and comprehensively uses physical and mechanical characteristics test,theoretical analysis,numerical simulation and other means to study the rock physics and mechanics under different stress levels and plastic damage states.It reveals the strain softening mechanism and capacity expansion characteristics of the surrounding rock of the deep roadway,constructs the deep rock mass strain softening constitutive model,analyzes the bolt(cable)tensile and shear fracture mechanism,and develops the bolt(cable)fracture The simulation unit model adopts the convergence-constraint method to carry out the analysis of the interaction mechanism between the surrounding rock and the support of the roadway and the stability evolution of the surrounding rock.The main research results of this article are as follows:Firstly,MTS 815 rock mechanics test system was used to carry out 6 kinds of rock triaxial cyclic loading and unloading tests under confining pressure.With the increase of confining pressure,the peak stress,residual strength and generalized cohesion of the rock sample increased significantly,the generalized internal friction and dilatancy angle gradually decrease.With the increase of the number of cycles,the plastic shear strain increases,the dilatancy angle and the generalized internal friction angle increase first and then decrease,and the generalized cohesive decreases accordingly.Secondly,aiming at the strain softening and capacity expansion characteristics of the surrounding rock,the secondary development of the strain softening constitutive model of the surrounding rock of the deep roadway was completed using the Fish language.FLAC3D simulation is used to solve the longitudinal deformation profile and ground reaction curve,calculate the support characteristic curve of the commonly used support structure of the roadway such as shotcrete,bolt(cable),U-shaped steel bracket,analyze the law of bolting shotcrete and U-shaped steel parameters on the stability control effect of roadway surrounding rockFinally,aiming at the problem that the cable unit embedded in FLAC3D cannot simulate the failure of bolt(cable)supporting structure,a bolt(cable)breakable simulation unit considering the coupling effects of tension,shear and tension-shear is established.Taking the roadway support project in the Zhujixi coal mine,FLAC3D is used to reveal the deformation law and force characteristics of the bolt(cable)fracture simulation unit.