Stability Analysis on the Movable Block Formed in the Underhand Cut-and-fill Drift under Horizontal Crustal Stress
The stability of surrounding rock in underground cavity is mainly affected by ground stress,and the horizontal crustal stress component is the critical influencing factor.According to the forming conditions and the stress state of the movable block formed in the underhand cut-and-fill drift,a stability analytic method considering the horizontal crustal stress was presented by vector algebra and mechanical analysis.Then the impact of the horizontal crustal stress on the movable block's stability was studied when the maximum horizontal crustal stress direction and the underhand cut-andfill drift direction were in different angles.Results showed that the stability of the movable block was closely related to the acted direction of the horizontal principal stress.The degree of impact on the stability of the movable block decreased gradually with the increase of the angle between the horizontal crustal stress direction and the underhand cut-and-fill drift direction.The block stability coefficient decreased faster when the angle changed during 0to 30degrees.As the angle increasing,the changes of the block stability coefficient tended to be gentle.Good results of this calculation method were achieved in engineering practice.