Study on abnormal failure laws of overlaying strata under directly passing collapse column

Abstract

When the working face passes a non-water filled collapse column，the overlaying strata of the working face can be damaged abnormally owing to the mining influence，which inevitably induces water inrush disaster.To study the abnormal failure laws of overlaying strata，the Jingfang coal mine was chosen as the engineering background in the study.A collapse column-surrounding rock fissure mechanical model was built by fully considering the formation of collapse column and geological characteristics of its surrounding rocks.Based on this model，the abnormal failure laws of overlaying strata were analyzed theoretically by combination of physical and numerical simulations.The results indicate that collapse column-surrounding rock fissure field and the mining fissure field were existent in the overburden rock with their own fracture distribution features.Under the influence of mining，some new destruction features were developed under the action of coupled fracture fields and the variation of collapse column-surrounding rock fissures.A concentrated destruction occurred around the collapse column.The new born fissures of bed-separated near the column side and longitudinal broken fissures were interconnected with the above two fissure fields.At the top of the column，the two types of new born fissures could be interconnected.The connected fissures around the collapse column and top of rock mass gradually increased ，which caused the hydraulic conductivity to be enhanced and the risk of water-inrush from roof to be increased.

Keywords

• collapse column
• physical simulation
• numerical simulation
• overlaying strata fissure