Optimization and application research of soft rock roadway support scheme based on AHP

Aiming at the challenge of weak and large deformation of surrounding rock and difficulty in control of coal transportation in Tucheng mine, the theoretical analysis, laboratory test and numerical simulation were used to reveal the deformation and failure characteristics of soft rock roadway and the cause of damage. Poor self-supporting capacity, unreasonable support design, complex stress environment and water erosion obviously were the main reasons for the instability of the roadway. Based on these, the analytic hierarchy process was applied to establish the evaluation index system, and proposed two engineering analog support schemes. FLAC3D were used to simulate the support effect of the two support schemes, and the anchor ( cable ) + grouting + U steel support schemes were chose. The solution can meet the requirements of the roof and two side of approaching quantities. The results of post-site monitoring showed that the overall deformation control of the surrounding rock under the new optimization scheme met the expectations. After 45 days, the convergence was shown stable and the convergence rate was less than 0.5 mm/d. The overall displacement was less than 70 mm, which fits the requirements of roadway support and has adequate support effect. © 2020, Editorial Office of Journal of Mining and Strata Control Engineering. All right reserved.