Stability Analysis and Support Control for a Jointed Soft Rock Roadway Considering Different Lateral Stresses

Abstract

The stability of coal mine roadways in jointed soft rock masses is an important issue for safe and efficient mining production in underground mines. Taking a main haulageway of a coal mine in Guizhou Province in China as the research background, the instability failure caused by large deformation of a roadway in a cracked rock mass was analysed, and its support control measures were put forward. First, the stability of the surrounding rock was evaluated by field investigation on the failure characteristics and statistics for the development of joints and fissures in the surrounding rock. Second, the corresponding numerical model was established by using FLAC3D software, and the influence of the lateral pressure coefficient λ on the plastic zone and principal stress were analysed quantitatively. In addition, the evolution process of the plastic zone over time was summarized. Furthermore, the key points of the reinforcement plan and support parameter design were provided on the basis of the technical approach for deformation control of the surrounding rock of the roadway. The original supporting scheme was optimized step by step, and the combined supporting scheme with “short bolt, long anchor cable and two-step grouting shell” serving as the main concept was put forward. Finally, the results of numerical calculation and field practice showed that the optimized scheme could effectively restrain the local deformation in the plastic zone of the surrounding rock of the roadway. The overall deformation was in a controllable range. In addition, the reinforced anchor cable was anchored to the deep part of the surrounding rock, ensuring the safety and stability of the roadway.