Stability analysis of hyperbolic coal pillars with peeling and high temperature effects

Abstract

In this present study, a twice-peeling model was established to analyze the hyperbolic coal pillars stability in underground coal gasification and then propose the concept of stripping degree to show model details for numerical simulation. The data shows that hyperbolic coal pillars stability can be analyzed through the twice-peeling model. Considering the coal pillars peeling and high temperature effects, one side of coal pillars will decrease 3 m, and the stability coefficient is 1.6 which has enough bearing capacity. When the arch depth ratio is 0.6, the critical condition for the coal pillar instability is reached. In this paper, underground coal gasification industrial test area still had strong bearing capacity after twice stripping, and there was no sudden instability. The research results can provide reference for the gasifier design and the stability of non-uniform coal pillars in the future.