Composite Roof Supporting Theory Of Roadside And Roof Governing Coordinately And Its Application To Deep Soft Rock In Chengjiao Mine

Chengjiao mine’s two level mining has comprehensively started now. With the increasing of mining depth, the corresponding increasing stress, and the worsening geological conditions, the past support form of shallow exploration can’t meet the demand of roadway support in deep surrounding rock. Especially in high-stress deep soft rock composite roof coal roadways, the problems of poor supporting effect are exposed increasingly, which is seriously affecting the normal production in mine. Therefore, the failure mechanism and support methods of composite roof coal roadways of high-stress deep soft rock in Chengjiao mine must be studied as soon as possible, in order to ensure the safe and efficient mine production.Research methods of mechanism analysis, numerical simulation, rock strength test in laboratory and industrial test was adopted. According to the present domestic and overseas Roadway support theory and technology, failure characteristics and deformation mechanism of high-stress deep soft rock composite roof coal roadways in Chengjiao mine two level were analysed deeply. Deep soft rock composite roof supporting theory of roadside and roof governing coordinately in Chengjiao mine and its corresponding support technology were proposed, which were experimentally applied in 21304 section transportation drift of Chengjiao mine, and the deformation of surrounding rock was successfully controlled. The research contents and conclusions are as follows:1)The characteristics of rock around coal roadway in Chengjiao mine two level was analysed. The ground stress of Chengjiao mine two level was calculated. Vertical stress of Chengjiao mine’s two level is v?=16.755 ~ 20.915 MPa, and the maximum horizontal stress is =24.308~29.068H? MPa. The strength of typical coal roadway surrounding rock of two level was tested in laboratory. Through the research results above, mining roadway roof of Chengjiao mine two level was determined as deep soft rock composite roof.2)The distortion and failure character of mining roadway of Chengjiao mine two level was summarized, and the damage mechanics model of composite roof Coal roadway was established. Through mechanical analysis, mechanical failure mechanism of omposite roof roadway was get. Different supporting structure was comparatively analysed with the methods of mechanical derivation and numerical simulation calculation, and the roadside and roof integrally supporting structure is optimum way. Based on the analysis above, composite roof supporting theory of roadside and roof governing coordinately in deep soft rock of Chengjiao mine was proposed.3)Aimed at low strength of roadside coal of Chengjiao mine two level, the failure mechanism of bolt supporting in soft coal was studied. The roadside reinforcement technology of coal roadways in Chengjiao mine two level and the soft coal reinforcement methods, including mutual-pulling anchor, were proposed.4)Based on the cmposite roof supporting theory of roadside and roof governing coordinately, the Chengjiao mine’s current roof supporting technology was optimized in three aspects, including anchorage body reinforcement, supporting accessories, and roof anchor, to meet the technical requirement of coal roadways in Chengjiao mine two level.5)The research conclusion and results were successfully applied in 21304 section transportation drift of Chengjiao mine, and the deformation of surrounding rock was controlled effectively.