Research on pressure relief technology of roof cracking caused by static expansion agent in No.1305 working face of Runhong Coal Industry
Based on the geological conditions of No.1305 working face in Runhong Coal Industry as the engineering background,static expansion technology for roof cutting and pressure relief in transportation roadways was adopted to avoid the lateral stress concentration on the coal pillar.By means of theoretical analysis,laboratory and field engineering test,the expansion force performance of static expan-sion agent was analyzed and tested,the drilling parameters of roof cutting and pressure relief under static expansion agent were calculat-ed and analyzed,and the detailed construction technology was designed.The results show that the maximum expansion force of the static expansion agent can reach 70 MPa and the duration is long,which can be used in coal or rock fracturing engineering.Drilling spacing,drilling diameter and drilling angle are the main parameters that affect the fracturing effect of static expansion agent.The static expan-sion pressure produced in the drilling acts on the drilling wall and can be maintained until the roof enters the goaf.Under the action of mine pressure,weight and static expansion force,the roof would appear three processes,including cracks,crack expansion and roof cracking and collapse.According to the specific engineering conditions on-site,the superposition of expansion stress can be formed un-der the joint expansion action of multi-component row drilling,which can play a better fracturing effect.The research results provide ref-erence for exploring and promoting non explosive roof fracturing technology in coal mines.
roof crackingstatic expansion agentrow spacing between drillingroof cutting and pressure relief
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