Research On Excavation And Support Technology In Deep&High Stress Chamber Group

With the increase of coal mining depth,it becomes more difficult to excavate and support underground roadway and chamber.Taking the-1150 chamber group in Anju coal mine as an example,the stability of surrounding rock and the support technology of pumphouse are studied.The main natural factors affecting the stability of deep chamber groups are the distribution of in-situ stress and lithological conditions.The average vertical stress in the area of the-1150 level chamber group is 28.2 MPa,which is basically equal to the weight of the overlying strata per unit area.The maximum horizontal principal stress is about 34.9 MPa,which is basically in the direction of NW-SE,and is basically consistent with the axial direction of the chamber group.The uniaxial compressive strength of fine sandstone in this area is 66.9 MPa,the elastic modulus is 8.6 GPa,and the strength of surrounding rock is high,which is conducive to the maintenance of roadway and chamber.The stability of deep chamber group is mainly affected by excavation,which is a complex process of dynamic and multi-factor coupling.Therefore,it is necessary to adopt dynamic construction mechanics to optimize the design of the excavation scheme of the adit group.Based on the elastoplastic theory,the stress changes in the excavation process of adjacent tunnels and Chambers are discussed.The numerical model of-1150 level chamber group was established,and the interaction in the excavation process of adjacent roadways and the stress superposition at the intersection of Chambers were studied.When the size of rock pillars between adjacent Chambers is small,the peak value of horizontal stress concentration increases and the vertical stress concentration area is connected due to mutual disturbance in the excavation process.The intersecting point in the adit is easy to produce stress superposition during excavation,and the stress concentration increases.The excavation process of the chamber group is divided into three stages and the construction optimization plan is formulated.The optimal construction sequence of each stage is determined through numerical simulation analysis as follows:The first phase,main body of water pump room,substation,pipe channel;The second phase,absorbing well niche B1B3,B2,electrical niche A1A3,A2,distribution well niche C1C2;The third phase,absorbing well A1A3,A2,distribution well B1B2,water distribution drift C.The stability control idea of surrounding rock in deep high-stress chamber group is put forward,that is,pressure relief,pressure relief,secondary support and high-stiffness support.The detailed construction plan is designed for anju coal mine-1150 horizontalchamber group and the field application is carried out.The research results can be applied to the excavation and support of deep high-stress chamber group in coal mine.