Research on law of front abutment pressure change of top-coal caving

Front abutment pressure has a greater impact on stability of mining roadway. The law of front abutment pressure of top coal caving was researched combined with numerical simulation and field tests at No. 8212 Tashan coal mining. The results showed that: front abutment pressure had a single peak, and it first increased then decreased when mining face moved forward. Peak position in numerical simulation and field tests was close, at 20 m and 18 m away from mining face respectively. Meanwhile, abutment pressure fluctuated in regular due to the periodically break of old top. Numerical simulation showed that amplitude reached at 14.5% of in-situ stress. It had a great impact of stability of roadway. Therefore, this phenomenon shouldn't be ignored. Research results analyzed changing characteristics of abutment pressure further based on the predecessors' research, providing reference for the supporting of roadway.