Mining Stability Criterion of Weakly Cemented Aquiclude and Its Application

Abstract

The effective discrimination of aquiclude mining stability is one of the important indexes for the feasibility judgement of water-conserved mining. Based on the mining-induced deformation characteristics of weakly cemented aquiclude and the water level change of weakly cemented aquifer in northwest China, a mechanical model of mining stability of weakly cemented aquiclude is established, and the mining instability criterion of weakly cemented aquiclude and its influencing factors are analyzed. The results show that the weakly cemented aquiclude has strong plastic deformation ability and mainly undergoes bending deformation during coal mining. Considering the mining-induced bending deformation of weakly cemented aquiclude and the groundwater pressure variation of the weakly cemented aquifer, the expressions of the deflection, stress components, and strain components of weakly cemented aquiclude are derived. Furthermore, the stress instability and strain instability criteria of the weakly cemented aquiclude are proposed. The influences of aquiclude thickness, elastic modulus, Poisson’s ratio, groundwater level, coalface length, and longwall panel length on the mining stability of weakly cemented aquiclude are analyzed. The research results are applied to the feasibility judgment of water-conserved mining in Xinjiang Ehuobulake Coal Mine, and the validity of the mining stability criterion of weakly cemented aquiclude is verified.