Study On Failure Mechanism And Support Of Thick Composite Roof In Roadway In Deep Well With High Stress

The strong demand for coal resources has promoted the rapid development of coal mining technology and the continuous increase of coal production.With the gradual mining of shallow burial coal seams,coal mining shows a pattern of deep mining and poor depositing and complicated geological structures region mining trends.With the increase of burial depth,a series of support problems have emerged.It is often difficult to deal with the problems of deep roadway with high strength due to the traditional support methods and support theories.Especially,Thick composite roof roadway support problem is particularly significant.Based on the current research status and supporting technology of the thick composite roof,this paper adopts the method of theoretical analysis,on-site investigation and numerical simulation to analyze the deformation of the extremely thick composite roof damage mechanism and support technology were studied,reached the following conclusions:(1)Based on the characteristics of the deep-earth high-stress composite super-thickness roof,a qualitative destructive process derivation analysis and mechanical calculations are performed for the common tensile failures andflexural separation failures,and the high-stress and deep-thickness composite roof tensile failures in deep wells are obtained.And the mechanism of flexural breakage from the layer.(2)By analyzing the relationship between the radius of curvature and the bending moment of each rock,combined with the previous calculation results,taking into account the stratification coefficient and the two groups of stability coefficients,the tensile stress formula is deduced,and the stability of the extremely thick composite roof is the original rock stress,the factors such as the width of roadway,the damage degree of the roadway,the mechanical properties of the roof,the thickness of the rock beam,the number of layers of the rock beam,and so on?Then I put forward a number of supporting principles and performed FLAC3 D numerical simulation of various factors ? This work Provides the basis for the design of support methods.(3)In order to study the special thick composite roof support methods,a special investigation was conducted on the engineering background of this study,the thick composite roof in Maidizhang Coal Mine,and the overall strength from the surface of the roof to the interior was found to be“ Weak-strong-weak-strong-very weak” and learned that the weak sandwich and1# coal are more prone to damage.(4)By calculating the curvature,the super thick composite roof can be regarded as consisting of three groups of rock beams.Combined with the on-site investigation,it is determined that the anchor sections of the arch-beam couplingsupport structure are respectively 0.6m~2.9m,3.05m~6.6m and 7.7m~10.3m.Based on the arch-girder coupling theory,a multi-arched-beam coupling theory including multi-level anchoring of deep roofs and walls were proposed.This theory provides a reference for the support of thick composite roofs.(5)Using the numerical simulation software to record and analyze the deformation and failure characteristics of the surrounding rock of the mining roadway,the support effects of different support schemes were compared and analyzed in a comprehensive way,verifying the multiple arch-beam coupling.The supporting methods of support theory have better support effects.(6)The rationality of the selected support methods and support parameters was confirmed through engineering application.