Experiment Study On Charcaterisic Of Deformation And Failure Of Roadway's Surrounding Rock And Its Controlling Technique In Deep Mine

With the continuous development of the deep coal resources and the building of the deep mines, the occurrence of the high stress problems becomes the dominating factor endangering the roadway rocks stability. Thus, the roadway supporting theory and technology for the shallow mining can hardly adapt the problems on the roadway rocks stability and supporting in the state of the high stress, which makes a new research topic on the roadway rocks stability and the safety of the roadway projects be put forward. Therefore, it is particularly important and urgent to study such problems as the deformation and damage mechanism of surrounding rocks and the support and reinforcement technique of the roadways. From this starting-point and combined with the National Natural Science Foundation Item"Deformation and damage process of surrounding rocks of deep roadway and mechanism of stability control"(50674083) and the entrusted project"Damage mechanism and control technique of surrounding rocks of deep roadway"from Shandong Yuncheng Mine, based on mining science, rock mass mechanics, elastic-plastic mechanics and fracture mechanics, the deformation and damage mechanism of the surrounding rocks of the deep roadway in the coal mines was studied with the similar material simulation, theory analysis, numerical simulation, site observation and engineering practice, then the support technique and method of the roadway in the state of the high stress is put forward. The major contents in this paper are as follows:The similar material simulation of first load and then excavation is carried out for the roadway in the state of the high stress with the test platform system for simulating the big scale 3D underground engineering. The failure characteristics of the roadway rocks are simulated in different support ways such as the pneumatic mandrel supporting structure self-designed and built, the collapsible supporting structure and nothing supported, the load transfer mechanism and the evolution rules of the principal stress during being loaded are gained with the main direction strain sensors and the convergence deformation laws are obtained with the displacement gauges.The failure characteristics of the roadway rocks given by the similar material simulation under the condition of high stress in different support ways are analyzed, the relationship between the evolution rules of the principal stress in the roadway rocks or at the driving face and the roadway deformation is studied and the affects of different support ways are analyzed though the convergence laws of the surface displacement of the roadway.Based on the deformation and failure characteristics and the broken range of the roadway rocks under the condition of high stress as well as the measured results of the deformation and failure of the excavated roadways actually by using the sight instrument, it can be shown that the measured results are in accord with that of the similar material simulation. The reason for the occurrence of the initial cracks on the surface of the roadway rocks is studied with the energy analysis method, then, combined with the fracture mechanics relevance theory, the expanding and linking process in the roadway rocks is analyzed. With the continuous evolution of the principle stress, the deep roadway rocks under the condition of high stress fails into the inside by the compressive-shear action. Finally, a few shearing and slippage cracks take place in the area of compressive stress concentration, which make the roadway instable. At the same time, the mathematical description of the shapes of the cracks is developed.Based on the analysis and research of the deformation and failure mechanism of the roadway rocks under the condition of high stress, the similar material simulation is verified by the numerical simulation with FLAC3D and the impacts of the coefficient of horizontal pressure and the cohesion on the size and the shape of the broken rock zone.Based on the results of the similar material simulation, theoretical analysis and numerical simulation, the control of the stability of the road-surrounding rocks is analyzed theoretically, then such control methods are put forward as the gradual supports, the timely stress restoration, the improvement of the stress state, consolidation and reparation, rock reinforcement and the reinforce for the key parts.For the existing problems on the supports of the deep roadway under the condition of high stress, based on the result of the theoretical analysis and the practice, the supporting project is designed with pertinence and the in situ engineering tests are carried out. It can be shown from the measured data that the supporting project used controls the big deformation and failure of the roadway rocks and improves the safety of the roadway, which verifies the feasibility of the project.