Characteristics and mechanical analysis of the collapsed accumulation body in the underground fault fracture zone

Abstract

ABSTRACT Based on the blockage of the rescue route of roadway caused by the collapsed accumulation body in coal mine underground fault fracture zone, the geological characteristics and accumulation form of fault fracture zone are analyzed. According to the theory of natural balance arch and elastoplastic theory, the height, the width of the accumulation body roof-fall area, the range of the accumulation body, and the height calculation formula of the accumulation body were derived. At the same time, the mechanical analysis of the accumulation body was carried out, and the calculation formula of the boundary force of the accumulation body was deduced, and the experimental verification was carried out by using the self-made experimental device. The results show that the collapse in the roadway of the fault fracture zone is mainly filled with rock fragments. The “self-organization” adjustment mode is divided into lateral movement adjustment, longitudinal movement adjustment and self-rotation adjustment; the maximum lateral instability width of the accumulation body, the longitudinal maximum collapse height of the accumulation body are related to the roadway height, roadway width, lateral stress coefficient, and the internal friction angle of the fragment filling body; the accumulation range is the total of the length of the fault fracture zone, the pre-decomposition zone, and the post-decomposition zone. The passive resistance is related to the bulk density of the block, the buried depth, the horizontal distance of the highest point of the accumulation body, and the natural repose angle; the correctness of the passive resistance calculation formula is verified by the experiment, but the formula has certain applicable conditions, depending on the ratio K of the particle size to the horizontal size of the accumulation body, the smaller the K value, the more suitable the formula is. The study provides theoretical and technical support for the implementation of the pre-repair roadway collapse form, rescue time, and the development of corresponding rescue programs.