基于岩石蠕变及D-P准则的深部巷道围岩弹塑性分析

为深入分析岩石蠕变及中间主应力对深部高应力软岩巷道围岩稳定性及分区变形特性的影响机理, 通过剖析长期荷载作用下深部巷道围岩的变形特征, 揭示了基于围岩蠕变特性的深部巷道围岩四分区变形机理, 并依据Druck-Prager准则及关联性流动法则考虑了中间主应力、岩体扩容及应变软化的影响, 推导出巷道围岩各分区应力、变形和半径解析解. 结合工程算例, 通过对现场监测数据以及不同力学模型的计算结果进行对比分析, 论证了本文理论的科学性, 并揭示了不同强度准则和围岩参数对深部巷道围岩各分区形态的影响规律. 结果表明, 忽视深部巷道围岩的蠕变特性将导致初始黏聚力的取值大于实际值, 从而造成围岩的理论承载能力大于实际承载能力; 在0, 0.7]区间内提高中间主应力系数可有效控制围岩塑性区及破碎区范围的扩展; 当初始黏聚力及内摩擦角减小时, 中间主应力系数对围岩塑性区、破碎区范围及巷道变形的影响力显著提高. 研究成果可为地下工程支护设计及围岩稳定性评估提供理论参考. 

ELASTOPLASTIC ANALYSIS OF SURROUNDING ROCK OF DEEP ROADWAY BASED ON ROCK CREEP AND D-P CRITERION

In order to deeply analyze the influence mechanism of rock creep and intermediate principal stress on the stability and zoning deformation characteristics of surrounding rock in deep high stress soft rock roadway, by analyzing the deformation characteristics of surrounding rock of deep roadway under long-term load, the four zones deformation mechanism of surrounding rock of deep roadway based on the creep characteristics of surrounding rock is revealed, the effects of intermediate principal stress, the rock mass expansion and the post peak strain softening characteristics are considered according to Druck-Prager criterion and correlation flow rule, and the elastic-plastic analytical solutions of stress, deformation and radius of four deformation zones of surrounding rock in deep high stress soft rock roadway are derived. Combined with the specific engineering example, through the comparative analysis of field monitoring data and calculation results obtained by using different mechanical models, the scientificity and feasibility of this theory are demonstrated, and reveals the influence law of different strength criteria and surrounding rock parameters on the zoning shape of surrounding rock in deep roadway. The results show that ignoring the creep characteristics of surrounding rock in deep high stress soft roadway will lead to the value of initial cohesion greater than the actual value, resulting in the theoretical bearing capacity of surrounding rock in deep high stress soft roadway greater than the actual bearing capacity. Increasing the intermediate principal stress coefficient in the range of 0, 0.7] can effectively control the expansion of plastic zone and broken zone of surrounding rock. When the initial cohesion and internal friction angle of surrounding rock decrease, the influence of intermediate principal stress coefficient on plastic zone, broken zone and roadway deformation of surrounding rock increases significantly. The research results can provide theoretical reference for underground engineering support design and surrounding rock stability evaluation.