Study on Failure Mechanism and Zoning Control of Weakly Cemented Roadway Adjacent Chambers

The strength of weakly cemented surrounding rock is low, and the bonding ability is weak. The rock forming roadway is affected by the stress disturbance after the excavation and support of adjacent chambers, which can lead to problems such as large deformation of the surrounding rock and significant differences in deformation areas. Through comprehensive theoretical analysis, on-site measurement, and numerical simulation, the distribution and evolution characteristics of stress in the surrounding rock adjacent chambers were studied. The results of this study indicated that, the surrounding rock stress crosses the adjacent chambers and forms a concentrated area near the weakly cemented roadway, and that the stress increase ratio of surrounding rock within the stress concentration range can reach 50%. A longer distance of the chambers from the weakly cemented roadway corresponds to a smaller surrounding rock stress concentration area. When the distance exceeds approximately 12 times the average height of the chambers, the surrounding rock stress concentration tends to disappear. According to the support concept of “allowable deformation” + “released pressure” + “restricted shape”, control countermeasures for surrounding rock at different levels are given, which are dominated by U-shaped steel + flexible material and are effective for controlling roadway deformation.