Application Of High Strength U Section Steel Holder In The Soft Rock Roadway Of Ning Village Coal Mine

The east main roadway and the partial chamber in Ningzhuang coal mine of Li Yuan coal mine in Pingdingshan are loose, weak and water swelling, and it has characteristics such as big deformation and rheology etc. In the original support ways of bolting with wire mesh and shotcreting and compressible U section steel support, the deformation of the excavated roadway is large; the excavated roadway is continued rheology; the largest deformation of the roadway is 412 cm; the average convergence rate is 2.5 mm/d in three months. Therefore, the original support way can not solve the problems of surrounding rock effectively such as big deformation and rheology etc. The main contents of this paper include the calculation and analysis of support capacity, the determination of physical mechanical parameters of rock, the analysis of numerical simulation of controlling surrounding rock of soft rock rheology roadway and industrial test. In the calculation and analysis of support capacity, calculate the semi-circular arch U29 section steel holder with the mechanical equation in structural mechanics, and obtain results:when the uniform load of holder leg is 0.62 times of uniform load of holder arch, the effects to support capacity of the bending moment and the normal force are same; when the uniform load of holder leg is less than 0.62 times of uniform load of holder arch, the effect to support capacity of the normal force is greater; when the uniform load of holder leg is more than 0.62 times of uniform load of holder arch, the effect to support capacity of the bending moment is greater. In the determination of physical mechanical parameters of rock, according to the geological conditions of the east main roadway, the physical mechanical parameters of rock of related roadway are determined, and the physical mechanical parameters of rock were reduced to the corresponding parameters of rock by the related formula, so as to provide effective and accurate data for the numerical simulation of controlling scheme of soft rock rheology roadway. In the analysis of numerical simulation of controlling surrounding rock of soft rock rheology roadway, firstly, the variations of semi-circular arch setion and horse-shoe section are compared and analyzed without support by the finite element simulation software such as ANSYS and FLAC3D, and obtain the conclution that the convergence of horse-shoe section is less than the convergence of the semi-circular arch section, so it can clearly be seen that the support effect of horse-shoe section is better than the support effect of semi-circle arch setion. Secondly, compare and analyze the distribution of the vertical stress, the horizontal stress, the shear stress, the displacement and the plastic zone of the east main roadway in the support ways of the bolting with wire mesh and shotcreting, compressible U section steel support and yield-rigid U section steel support, and obtain the conclution that the support effect of yield--rigid U section steel holder is better than the support effect of the bolting with wire mesh and shotcreting and compressible U section steel support. In the industrial test, observe the deformation of the partial roadway and chamber of the east main roadway and analyze the failure reasons of the bolting with wire mesh and shotcreting and compressible U section steel support; determine the late convergence rate of the roadway; according to the principle of equivalent rectangular, calculate the displacement of the roadway with yield-rigid U section steel support in order to make sure whether the displacement meets the requirement. According to the above analysis, this paper propose the support way of compressible-rigid U section steel holder for controlling the surrounding rock, and the support way can control big deformation and rheology of the surrounding rock effectively, and achieve good support effect.