Surrounding rock control technology with synergetic support and pressure relief for gob-side entry driving in extra-thick coal seam
In order to solve the supporting problem of gob-side roadway in large scale plastic zone of whole coal using anchor-mesh-cable,taking the 8204-2 small coal pillar working face of Tashan Coal Mine as engineering background.We revealed the supporting mechanism of bolt and anchor cable for large-scale plastic zone of gob-side roadway.The bolt support acts on shallow secondary crushing area of surrounding rock,forming shallow continuous load-bearing structure;anchor cable acts on the stable surrounding rock in deep three-way stress state to form a larger range of continuous stable bearing structure.Based on this,the calculation method of effective length of bolt and anchor cable was further clarified.And the synergetic control technology of surrounding rock for gob-side entry driving in extra-thick coal seam was formed,based on the support of anchor-mesh-cable with high pre-tightening force and high strength,and using abrasive water jet roof cutting pressure relief in hard roof,large diameter borehole pressure relief in roadway side,floor pressure relief slotting relief as auxiliary.The engineering application results show that,the maximum deformation of surrounding rock of test roadway was less than 700 mm,which met the use requirements.
extra-thick coal seamsmall coal pillargob-side entry drivingsurrounding rock controlsynergetic support and pressure reliefdouble-layer continuous load-bearing structure
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