Numerical Simulation Research On Pressure Relief Groove Mechanism Of Deep Roadway Floor In Gaocheng Coal Mine

This paper takes the serious floor heave phenomenon of the deep transportation main roadway floor in the south wing auxiliary mine of Dengfeng city Gaocheng coal mine as the engineering research background,and analyzes the causes of the floor heave.Based on comprehensive research on the existing technology of floor heave treatment,and in accordance with the inevitable trend of mechanized construction of excavation roadways,this paper has carried out research on the influence of the depth and width of the pressure relief groove on the deformation of the floor and the stress distribution of the surrounding rock.The parameter design of the machinery provides engineering data support;at the same time,the Mohr-Coulomb and Elastic constitutive models in FLAC^3D are used to simulate the filling materials in the pressure relief tank with different mechanical properties,and the different positions in the pressure relief tank are filled with different sizes and properties.The influence of different materials on the distribution of deformation,stress,and plastic zone provides a reference for the construction process after mechanical grooving.After research and analysis,the following results are obtained:（1）The mechanics model of the roadway floor is established using elastic theory,and the deformation and failure of the floor are briefly analyzed.Using rock mechanics,the changes in the stress distribution state of surrounding rock before and after floor slotting were analyzed,and the mechanism of stress relief by floor slotting was studied.（2）By simulating the excavation of pressure relief grooves of different sizes in the floor,the plastic zone distribution,stress changes and floor deformation around the roadway are studied and analyzed.The results show that:too shallow groove depth or too small groove width cannot play the role that satisfactory pressure relief effect.However,when the groove depth and width are excessively increased,the increase in pressure relief effect will be greatly weakened,and even the already brought pressure relief effect will be weakened.The proper size of the pressure relief groove can control the growth of the floor heave,increase the range of the pressure relief area around the roadway,transfer high stress to the deep part of the surrounding rock,and eliminate the stress concentration phenomenon at the bottom corner of the roadway.（3）By using the Mohr-Coulomb constitutive model to simulate the filling material in the pressure relief groove,the strength,rigidity,size and filling position of the filling material are studied and analyzed.The results show that:when the strength,rigidity and size of the filling material are too small,it cannot be enhanced pressure relief effect.Excessive material strength will cause the filling material and the two sides to squeeze the bottom rock layer together,which will increase the floor heave.Excessive material rigidity will prevent the filling material from deforming in harmony with the rock formation and weaken the pressure relief effect caused by the filling of the groove.Excessive material size will cause different degrees of stress concentration inside the filling material and reduce the range of low stress areas around the roadway.When the material filling position moves in the pressure relief groove from top to the bottom,a tensile stress zone will appear in the surrounding rock above the filling material and a large range of stress concentration will occur inside the material.At the same time,the high-level stress zone will continue to approach the bottom plate.The drum volume also gradually increased.（4）By using the Elastic constitutive model to simulate the filling material in the pressure relief groove,the rigidity,size and position of the filling material are studied and analyzed.The results show that the rigidity of the filling material in the groove changes from small to large,the inside of the material generate that the stress concentration area that decreases firstly and then tends to be stable.The floor heave volume presents a trend of firstly decreasing and then increasing;high-level stress gradually shifts to the deep rock.Changing the size and filling position of the filling material exhibits the same changes as when using the Mohr-Coulomb constitutivemodel.Through comprehensive analysis of the simulation results of the two types of filling materials,it is concluded that the appropriate filling material is filled in the appropriate position in the pressure relief groove,mainly through its own properties to absorb the deformation of the floor and adjust the stress distribution state of the surrounding rock to enhance the effect of pressure relief.This paper contains 73 figures,16 tables and 82 references.