Research On Coal Pillars Retention Method And Safety Assurance Technology Of The Fully Mechanized Caving Face Under Complex Conditions

With the continuous improvement of the intelligence degree of coal mine mechanization and the continuous upgrading of underground equipment,the intensity of most coal mining in China is constantly increasing,and the number of mines affected by the instability of coal seams and the development of geological structure is increasing day by day,if not to adopt targeted support design,the roadway deformation is serious,the amount of repair is large,and the support is difficult.Mine safety and efficient mining is more difficult.Based on the engineering background of the 8103 working surface back-mining roadway of Dong Zhou Yao mine,this thesis makes an in-depth study on the arrangement of the work surface roadway of small coal column under complex conditions and the technical measures of safety and security by combining theoretical analysis,numerical simulation and field test.Firstly,the relatively complex geological conditions of 8103 working surface are analyzed and ground stress test is carried out.Secondly,based on the theory of bullet plasticity,a model of dynamic analysis along the air laneway is established,and it is calculated that the range of 8103 working surface along the lateral stress reduction area is 5.32 m to 8.87 m,and the numerical simulation of the remaining 4m,5m,6m,7m and 8m coal columns by Flac3 D is used to determine the reasonable size of the coal column width by taking into account various factors.Using Flac3 D to carry out numerical simulation of the impact range of the working surface forward support pressure,taking into account the effect of the length of the recovery equipment,the pressure of the front support of the work surface and the working surface cycle to press the width of the stop coal column,it was initially determined that the width of the reasonable stop coal column was 80m;By analyzing the influencing factors of roadway deformation and destruction under complex conditions,the design of support scheme for 5103 lanes and the on-site industrial test were carried out.On-site observation shows that the two groups of the maximum transfer amount 65 mm in the process of roadway excavation,the maximum transfer of the top base plate 57 mm,the maximum transfer amount of the two groups during the face recovery 355 mm,the maximum near amount of the top bottom plate 135 mm,and tend to stabilize.Finally,a technical system of safety and security along the empty excavation lane is constructed,and targeted safety and security techniques and measures are put forward for the hidden dangers such as gas over limit,coal spontaneous combustion in the mining area,adjacent work surface burst water and over-steady loading chamber.The deformation of the roadway surrounding rock is effectively controlled,which ensures the normal mining replacement and safe production of the mine,and has important guiding significance for the scientific design of the support scheme along the empty roadway under complex conditions,and the safe and efficient production of the mine.There are 66 figures,14 tables and 82 references in this thesis.