Stability analysis and support optimization for soft rock large chamber in western China

MA Zhonghui

doi:10.11799/ce202512007

Abstract：To address the challenges associated with unclear deformation mechanisms and support design difficulties for large chambers in soft rock strata in western China,an underground loading chamber in the Ordos mining area was investigated.An integrated approach combining three-dimensional numerical simulation(FLAC3D)and field monitoring was employed to analyze the stability and deformation evolution of the chamber after excavation and support.The simulation results reveal significant deformation at the chamber roof and its junction with the inclined shaft.The thickness of the plastic zone was determined to be approximately 6 m in the sidewalls,5 m in the roof,and 5.5 m in the floor,indicating a necessity for reinforcement using anchor cables with lengths of 7.5 to 8 m.Field monitoring data show that,the loads on bolts and cables increased rapidly upon support installation and then stabilized.Monitoring points inside the chamber stabilized in about 20 days,while those in stress concentration zones stabilized in about 15 days.All measured loads were below the ultimate breaking capacity,confirming the safety and reliability of the support system.The findings provide critical parameters and a theoretical basis for the support design of large chambers in soft rock strata in western China.