| Shallow coal resources in China are basically exhausted.With the gradual transfer of mining to the deep,the stress environment of surrounding rock is becoming more and more complex.The stability control of surrounding rock in deep roadway is becoming increasingly prominent,which brings many problems to the support of deep high stress soft rock roadway.Aiming at the problems of poor surrounding rock stability,serious deformation and anchor cable failure of 131 transportation uphill roadway in Panjiang Tucheng Coal Mine,the supporting technology of high stress soft rock roadway was systematically studied by theoretical analysis,numerical simulation and field industrial test.The main research results are as follows:(1)Four definitions of soft rock are given,and the types of soft rock are divided.The mechanical properties of soft rock engineering are discussed.It is pointed out that the main mechanical response characteristics of soft rock are large plastic deformation,water swelling,disintegration and easy disturbance.The deformation and failure mechanism of high stress soft rock roadway is systematically analyzed.The deformation and failure characteristics of soft rock roadway are summarized.The eight basic principles of soft rock roadway support are proposed.(2)The causes of roadway deformation and failure in Tucheng Coal Mine were analyzed,and the supporting countermeasures of high-stress soft rock roadway were formulated.The principle of secondary double shed grouting strengthening support was revealed,and the synergistic bearing effect of support body and surrounding rock was discussed.The combined support technology and support efficiency of soft rock roadway were discussed in detail.By establishing the mechanical analysis model of'surrounding rock-supporting body',the calculation formulas of stress and strain in three zones of roadway surrounding rock are deduced.(3)The basic algorithm,operation principle and model establishment principle of FLAC3D numerical simulation software are introduced.Combined with the field geological data,two kinds of composite support schemes‘bolt+anchor cable+shotcrete+U-shaped steel'and‘bolt+anchor cable+grouting+double U-shaped steel'are proposed.A three-dimensional numerical model is established to compare and analyze the displacement variation and plastic zone distribution of roadway surrounding rock under the condition of excavation.The simulation results show that after the implementation of the composite support scheme,the distribution range of plastic zone shrinks,the deformation of surrounding rock decreases significantly,and the roadway support effect is good.(4)The original support scheme was optimized and applied in the field,and the deformation of roadway section was investigated.After the deformation of surrounding rock reached the stable stage,the maximum subsidence of roadway roof was 68.17 mm,the floor heave was 63.28 mm,and the extrusion of two sides was 71.36 mm.The monitoring results show that the application of shed grouting support technology can effectively improve the bearing performance of surrounding rock and prevent the deformation and failure of roadway. |
PDF Full Text Request