Study On Support Technology Of Top Coal Roadway Along The Bottom With Small Coal Pillar Of Thick Coal Seam In Shanzhai Coal Mine

At present,the proportion of China’s thick-seam coal is for 40%～60% of total coal reserves.The deformation process of roadway in thick coal is complicated and the supporting is hard in different geological conditions.Therefore,the optimization of roadway support technology and the increasing strength of surrounding rock contribute to the long-term sustainability of the roadway.Based on the engineering background of3506 return airway in Shanzhai Coal Mine,aiming at the characteristics of high stress,large deformation,serious subsidence and deformation of roof,obvious internal movement and contraction of two sides,and destruction of supporting components,this thesis analyzes the deformation and failure characteristics and stability influencing factors of roadway around the stability of surrounding rock of roadway by means of theoretical analysis,mechanical analysis,numerical modeling and site test.The supporting technology of roadway with small coal pillar along the bottom of top coal is studied.The main conclusions and achievements are as follows :1)The related engineering geological parameters of surrounding rock of small coal pillar roadway in Shanzhai Mine were determined According to the measurement of ground stress,strength of roadway surrounding rock and releasing circle,it is shown that the fractures in the shallow part of the roadway rock are developed,and the deep part is relatively complete.It can be judged that the 3506 return air gateway is a deep buried thick medium hardness coal seam roof roadway.2)The mechanical model of roof stability analysis of typical small coal pillar roadway along the bottom is established Based on the characteristics of roadway layout horizon,the mechanical model of small coal pillar roadway along the bottom supporting top coal is established.Through the analysis of the maximum tensile stress under the condition of roof subsidence,the use of high prestressed diffusion anchor cable echelon support can reduce the load of coal rock beam,reduce the load of two sides,increase the thickness of top coal appropriately,and reduce the span of roadway can improve the stability of roadway surrounding rock.3)The influencing factors of surrounding rock deformation and failure stability of small coal pillar roadway along the bottom of thick coal seam are revealed According to the numerical model to simulate the deformation and failure characteristics of the roadway,the results show that the surrounding rock has the characteristics of high stress,large deformation,rock mass fracture development,serious internal movement of the two sides,and low overall bearing capacity.According to the mechanical model and numerical simulation,the key factors which affect the stability of roadway are the low global strength of surrounding rock,the large buried depth,the high ground stress and the different stress state of the two sides.4)The combined support technology of roof and side of small coal pillar roadway along the bottom of thick coal seam is proposed Based on the research on the support technology of the top coal roadway and the small coal pillar roadway,the bolt cable support technology of the small coal pillar roadway along the bottom of the thick coal seam is proposed.The roof echelon support is mainly used to control the roof subsidence deformation and improve the stability of the surrounding rock.The combined support of ’ four high bolts ’ and high resistance yielding anchor cable can strengthen the strength of surrounding rock in deep high stress and large deformation roadway and improve the ability of weak rock mass to resist deformation and failure.The numerical simulation support effect shows that the optimized support scheme has smaller roadway deformation and stronger surrounding rock bearing capacity.5)The field application of optimized support scheme in 3506 return airway of Shanzhai Coal Mine meets the requirements of efficient and safe production Based on the bolt and cable support technology of small coal pillar roadway along the bottom of thick coal seam,the field practice was carried out in 3506 return airway of Shanzhai Coal Mine.The field mine pressure observation results show that After the parameter optimization of the support scheme of the roadway,the maximum sinking capacity of the roof plate is 120.9mm,and the maximum total internal migration of the two groups is 187.4mm,and the stability of the surrounding rock of the roadway is effectively controlled.There are 54 figures,11 tables and 73 references in this thesis.