Study On Microseismic Release Of Surrounding Rock And Support Damage Evolution Of Underground Caverns

Rock and concrete are two common engineering materials with different mechanical property and failure mechanism. The underground cavern equivalent of rock and concrete are surrounding rock and supporting structure. The stability of underground cavern depends on the stability of surrounding rock and supporting structure, so it has important significance to research the failure mechanism of surrounding rock and supporting structure for the stability of underground cavern, as important as to research the microseism release of their interaction.The main works and achievements are as follows:(1) To research the microseism release mechanism for the failure process of rock and concrete, the press and tension test of concrete are done, as good as the press test of rock. The study finds that the press process of rock and concrete has four periods, that the tension test has only one period named increasing all the time of microcrack, that the tension strength is lower than compress strength, that particle diameter has bigger influence for the tension strength.(2) The numerical simulation on the interaction microseism release of surrounding rock and supporting structure is done from three aspects of supporting system, excavate ways and different angle faults. Viewing the distribution condition of shear stress and microseism events, supporting system is indispensable because it and supporting structure share the stress from rock mass. The surrounding rock may crack in the step method, so the supporting structure must timely under the condition of high stress. Under the circumstances of horizontal fault, fault with an angle of 30 degrees and fault with an angle of 45 degrees, the cavern with horizontal fault fails latest, as you can see that horizontal fault does less damage to the stability of cavern.(3) After processing the microseism monitoring data of underground house in dagangshan, on the basis of space-time distribution regularity of surrounding rock and supporting structure, the stability of house is analyzed from three aspects which they are distribution regularity, fail microseism distribution, microseism influence factor. The analysis shows that the microseism events around the house mostly have a close correspondence with construction activities, that the hypocenter is far away from the house, that the magnitudes of events is small without big events, that the displacement caused by microseism is very small. Based on these, the underground house is stable. After caved area is supported which caused by fault, it is analyzed from the angle of space, magnitude, and displacement. According to the analysis result, the caved area has no possibility to fail again under the combined influence of surrounding rock and supporting structure, and the underground house is stable.