| In order to alleviate the difficulty of mine replacement,gob-side roadway driven heading for adjacent advancing coal face is successfully applied in some mines.With the increase of mine output,the mine replacement may face even more tense situation.However,due to the unique dynamic pressure influence of the gob-side roadway driven heading for adjacent advancing coal face in shallow coal seam mining,the surrounding rock control of roadway faces the following problems: the roof is difficult to form a stable articulated structure,the stress environment of roadway is complex,the bearing capacity of coal pillar is insufficient,and the roadway support strength is insufficient.Therefore,it is of great significance to master the law of mining pressure in working face and select the appropriate mining and driving mode for roadway surrounding rock control.Based on the engineering example background of the auxiliary transport groove 509 driven heading for adjacent advancing working face in Madiliang Coal Mine.The mining pressure appearance law of fully mechanized caving face in shallow coal seam,the influence of coal pillar width on the surrounding rock stress environment of roadway and the control technology of surrounding rock of gob-side roadway driven heading for adjacent advancing coal face are systematically studied,and industrial experiments are carried out to verify the supporting effect.The main research conclusions obtained are as follows:(1)In the shallow buried area of 507 working face,the periodical pressure step and dynamic load coefficient are enhanced,the basic roof is difficult to form a stable bearing structure,presenting a "stepped" subsidence.The basic roof is an overhanging beam structure,and the relationship between the lateral limit suspended span and buried depth is negative exponential;the influence range of the advanced support pressure of the working face is about 60 m,and the peak stress is about 10m;the influence range of the lateral support pressure is about 40 m and the stress peak is about5 m.(2)The formula for solving the plastic zone width of rectangular tunnel is established and Lode constant was introduced to characterize the principal stress,and the influence of intermediate principal stress on the plastic zone width of rectangular tunnel was analyzed;numerical simulation is used to analyze the influence of the pillar width on the surrounding rock stress environment.When the pillar width is larger than the lateral plastic zone of the roadway,the wider the pillar width,the smaller the surrounding rock stress and breakage degree,and finally maintain stability.(3)The advantages and disadvantages and applicable conditions of different mining and tunneling methods are compared and analyzed,namely,working face mining when roadway stops tunneling,roadway excavation when working face stops mining and roadway driven heading for adjacent advancing coal face.The minimum pillar width under different ways in Madiliang coal mine are determined,which are10.5m,13.5m and 15 m respectively.(4)The obvious deformation range before and after the roadway is analyzed,and the specific range of the strengthened support section of the gob-side roadway driven heading for adjacent advancing coal face is determined to be +65m～-170 m.According to the soft and hard characteristics of the roof strata,the combined anchor cable is added to strengthen the support,forming the bearing circle of deep and shallow surrounding rocks.According to the surrounding rock control scheme,industrial experiments have been carried out.The observation results show that the surrounding rock is stable,the roof separation layer is very small,and the section has no obvious deformation;the stability of coal pillar is observed by optical fiber,and the degree of disturbance is consistent with the theoretical calculation and simulation results.Figure 55 table 11 reference 84... |
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