Study On Stability Control Of Surrounding Rock Of Deep Large Section Chambers

With the increasing intensity and depth of comprehensive mechanized mining of coal resources,the mine is faced with the shortage of gangue discharge and lifting capacity.Based on this,the in-situ sorting and filling technology of coal gangue is proposed.In order to ensure the safe and efficient application of this technology,the stability control of surrounding rock in large cross-section chambers and chambers has become an urgent problem.In this paper,the large section chambers in the coal gangue separation system of Xinjulong coal mine is taken as the research object,and a combination of theoretical analysis,numerical simulation,laboratory tests and field measurements is used to study the stress field of the surrounding chamber of the chamber.Displacement field and plastic area distribution characteristics,and based on this,the stability control technology of the surrounding rock of the Yanshi Group is proposed.The main research results are as follows:(1)The mechanical model of the roof of the chamber was established,and the displacement distribution law of the variable-section beam at different positions was determined.The displacement of the roof rock beam increased with the increase of the buried depth and the span of the rock beam.The thickness increases and decreases;at the same time,it is determined that the deformation process of the roof of the chamber includes two stages: the initial deformation of the roof surrounding rock and the later deformation of the roof surrounding rock.(2)The relationship between the width of the limit equilibrium zone of the surrounding rock and the width of the rupture zone is studied.It increases and decreases with the increase of cohesion and internal friction angle and elastic modulus of the interface position;the proportionality coefficient increases with the increase of the burial depth,Poisson's ratio of the rock mass,and compressive strength of the rock mass,and softens with strength The strain,the friction angle in the rock mass and the elastic modulus of the rock mass increase and decrease.(3)The mechanical model of cylinder with wall rock is established,and the distribution law of initial displacement and tensile stress at different positions of wall rock is determined.The numerical calculation method determines that as the width-toheight ratio of the chamber increases,the amount of roof subsidence becomes larger,while the deformation of the surrounding rock of the upper part decreases;as the contact strength of the contact surface decreases,the amount of subsidence at the roof position changes less,and the deformation of the surrounding rock increases,and the maximum displacement of the surrounding rock of the gang is concentrated in the upper and middle positions of the surrounding gang.With the increase of the lateral pressure coefficient,the displacement of the roof of the chamber and the surrounding gang gradually increases.(4)The calculation formulas of the vertical stress and concentration factor distribution of the location of the roadway crossing point were established,and the numerical analysis method was used to analyze the stress field,displacement field and plasticity of the surrounding rock under different crossing point angles,lateral pressure coefficients,and chamber section sizes The distribution characteristics of the zone determine the reasonable intersection angle is 90 degrees,and the optimal lateral pressure coefficient is the same as the horizontal pressure coefficient in the two horizontal directions.At the same time,the cross-sectional size of the chamber should be minimized.(5)A mechanical model for the bearing of rock pillars was established.It was determined that the average stress on the rock pillars decreased with the increase of the width of the rock pillars and the reduction of the cross-section size of the rock pillars.The numerical calculation method was used to determine the extension depth of the surrounding rock plastic zone,the range of the fracture zone,the roof subsidence and the horizontal displacement of the surrounding rock in the area where the location of the bifurcation point and the width of the pillar were small.The surrounding rock of the chamber group adopts the anchor-net cable spraying support form,which has better onsite support effect,and can realize the stability control of the surrounding rock of the chamber group.This thesis has 67 Figures,15 Tables,and 98 References.