Research on Overburden Failure Characteristics Based on the Theory of Plates and Shells

Abstract

To reveal the overburden failure characteristics during backfill mining, theoretical analysis based on the theory of plates and shells and field measurements were combined. Based on the theory of plates and shells, a mechanical model for the overburden failure mechanism during backfill mining was established, through which the fracture conditions of overburden during backfill mining were judged. By analyzing the fracture process and revealing the fracture mechanism, the fractured zone in overburden during backfill mining was found not to develop uniformly, but changed in a leaping manner. Field measurement was conducted taking the 1327 working face in Xima Coal Mine (Shenyang City, Liaoning Province, China) as an example to monitor and analyze the roof-to-floor convergence (RFC), strata behaviors at the working face, and overburden failure during backfill mining. Monitoring results show that the distance between the monitoring points and the working face was highly consistent with the periodic weighting interval when the RFC increased in a leaping manner; the RFC grew in a leaping manner after each roof weighting, as well as the fractured zone. By monitoring and analyzing overburden failure, it was determined that the maximum height of the fractured zone was 10.7 m and a leaping phenomenon was present in the development process of the fractured zone. The conclusions of theoretical analysis were completely consistent with those of the field measurements, thus confirming the leaping development of the fractured zone in overburden during backfill mining.