Instability Mechanisms and Control of Weakly Cemented Soft Rock Roadways Under Alkaline Water Conditions

Weakly cemented soft rock roadways in western mining areas are highly vulnerable to deformation and failure under the influence of alkaline groundwater, posing serious challenges to safe coal mining. With the 11602 transportation roadway in the Dananhu No. 7 Mine, Hami, Xinjiang as a case study, this paper investigates the deformation and instability mechanisms of such roadways and develops targeted control measures. Field monitoring, numerical simulations, and theoretical analysis reveal that alkaline water erosion significantly reduces the bearing capacity of weakly cemented mudstone, leading to progressive instability of the surrounding rock characterized by “initial unloading–plastic failure–deep stress transfer–sustained creep.” Roof separation is concentrated within the shallow 3.0‐m zone, exceeding the control range of bolts, while floor heave is intensified by stress transfer and hydration expansion of mudstone. To address these problems, an optimized support system of “short–long anchor cables, shotcrete reinforcement, and retained floor coal” is proposed. Numerical results and field tests demonstrate that the optimized scheme reduces roof subsidence and floor heave by more than 70% and effectively suppresses long‐term creep, ensuring roadway stability. The findings provide both theoretical insights and practical guidance for the support of weakly cemented soft rock roadways in alkaline water environments.