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为了确定卸压程度,降低卸压过程中围岩强度弱化对巷道稳定的不利作用,基于应变软化准则建立了变形压力的力学模型,依据变形压力的变化规律分析了有控卸压机理,并提出了“临界塑性区半径”作为有控卸压的判定准则.结合某软岩大巷的有控卸压支护实践,确定该巷道的“临界塑性区半径”为7.78 m,并将该结果应用于有控卸压支护参数的设计.工程应用表明,通过对卸压程度的合理控制,不但有效释放了围岩的变形能减小围岩对支护体的变形压力,并能降低围岩强度弱化对围岩稳定的不利作用,提高二次锚杆支护效果,保证了支护强度满足要求,使巷道处于长期稳定状态.
In order to determine the degree of pressure relief and reduce the detrimental effect of surrounding rock strength weakening on the stability of the roadway during pressure relief, a mechanical model of deformation pressure was established based on the strain softening criterion. The controlled pressure-relief mechanism was analyzed according to the variation law of deformation pressure The critical radius of plastic zone is set as the criterion of controlled pressure relief.Based on the controlled pressure relief support practice of a soft rock roadway, the “critical plastic zone radius” of the roadway is determined to be 7.78 m, And the results are applied to the design of controlled pressure relief support.The engineering application shows that through the reasonable control of the degree of pressure relief, not only the deformation of surrounding rock can be effectively released, but also the deformation pressure of the surrounding rock can be reduced, And can reduce the weaker effect of wall rock strength on the stability of surrounding rock and improve the secondary bolt support effect to ensure the support strength to meet the requirements so that the roadway is in a long-term steady state.