Research on the evolution patterns of plastic zones in rock masses of multi-disturbance roadways and support control measures

The dynamic response characteristics of stress redistribution in roadway surrounding rock and the distribution patterns of plastic zones during different stages are pivotal to controlling rock mass stability. Addressing the vulnerability of retained roadways to repeated mining impacts from adjacent working faces under dual- or multi-roadway layouts, this study examines the 22,104 auxiliary transport roadway at Shangwan Coal Mine. Employing a combined approach of field investigations, theoretical analysis, and numerical modelling, it investigates the dynamic response characteristics of stress redistribution and the distribution patterns of plastic zones throughout the roadway’s entire lifecycle. Results indicate that during the overlapping mining activities of the 22,104 and 22,105 working faces, the evolution of the plastic zone within the 22,104 auxiliary transport roadway’s surrounding rock can be divided into four distinct phases based on its expansion morphology during the initial mining phase. During the secondary mining phase, the plastic zone evolution comprises three phases. When the magnitude and direction of stresses acting on the roadway rock mass change, the morphology of the plastic zone evolves from circular to butterfly-shaped, accompanied by a degree of deviation. Existing active support methods fail to anchor unstable rock within the plastic zone to stable rock. Based on the aforementioned evolution patterns of the rock mass plastic zone, a reinforcement support strategy suitable for the 22,104 auxiliary transport roadway is proposed.