Research On Mechanism And Control Technology Of Floor Heave In Deep And Soft Rock Chamber

It has always been a key technical problem how to control chamber’s floor heave in the field of coal at home and abroad. Although many experts and scholars have carried on certain research and exposition in this field, there are a lot of difficulties to reduce the deformation of floor in deep, high stress and soft rock roadway. This dissertation takes-848m charge rectification chamber roadway of Huainan Mining Group Pan Yidong Coal Mine as the engineering research object. Through on-site survey, laboratory test, and in-situ test, it obtained stress distribution Around Roadway, plastic range of roadway surrounding rock and other geological situation of construction in the original supporting condition of roadway.The occurrence mechanism and important influencing factors of floor heave of deep, high stress and soft rock roadway are analyzed; and the control measures are studied.So the method of reinforcing roadway roof and floor and governing roadway sides to control floor heave is proposed in this paper. According to the theory of modern mechanics mechanism, the mechanism of controlling floor heave is discussed. Based on the principle of strengthening load-carrying arch and the principle of weakening stress, it discussed the mechanics mechanism of that floor grouting and the anchor wire at the roof and floor control floor heave:①the principle of weakening stress—With the anchor wire at the roof pulling radial pressure on the load-carrying arch of loose circle of surrounding rock, the compression force passing from top of the breaking rocks over the two cross sections of load-carrying arch is lessened, thereby greatly reducing failure stress and radial strain on both sides of load-carrying arch. And it has an important role to effectively decrease the support pressure of surrounding rock. Therefore, floor heave is controlled effectively.②the principle of strengthening load-carrying arch—Strength and stability of the load-carrying arch will be enhanced after performing mud grouting in the loose circle of surrounding rock, first of all, it can make the loose circle of surrounding rock form a complete closed structure, so as to greatly improve bearing capacity of the pressure arch. Second, it can enhance bearing capacity of the lower part of load-carrying arch, thus improve the resistance of the lower force part. Finally, it can put out the water in the loose circle of surrounding rock, thereby eliminating the phenomenon that floor rock became soft after soaking in water. A three-dimensional numerical model is established by the nonlinear finite element software ABAQUS. The deformation and stress states of roadway are analyzed comparatively with reinforced floor and with non-reinforced floor. The result of numerical simulation shows that the anchor wire of floor can greatly reduce the deformation of floor and improve the stress state of roadway floor. According to the damage condition of floor heave of-848m charge rectification chamber roadway, an comprehensive supporting technology of bolt-mesh-cable supporting together with U shape shed supporting, the anchor wire of floor and grouting consolidation is proposed in this paper. And a detailed description is given of the implementation process, sequence and method of supporting scheme. It solved the Technical Problem of construction that the anchor wire at the floor is carried out simultaneously together with floor grouting.The deformation of roadway is monitored comparatively with reinforced floor and with non-reinforced floor, and field monitoring data indicate that floor heave is successfully controlled with the anchor wire and grouting consolidation.