考虑流变和中间主应力的巷道围岩变形分区

Deformation division for surrounding rock of circular roadway by considering rheology and the intermediate principal stress

  • 摘要: 考虑流变特性,将巷道围岩分为弹性区、塑性硬化区、塑性软化区和塑性流动区,并考虑围岩峰前应变硬化、峰后应变软化、扩容特性及中间主应力的影响;基于Drucker-Prager准则推导了各分区应力、位移和半径的封闭解析解,然后以实例为基础分析了围岩变形的影响因素。研究结果表明:中间主应力和围岩流变特性对巷道围岩位移和塑性区的大小均具有重要影响且中间主应力表现出强烈的区间性,在一定范围内提高中间主应力能够有效的控制巷道变形和塑性区的扩展。理论研究及工程实际中,若忽视围岩流变特性则无形中“高估”了围岩岩性,不利于巷道长期稳定性评估及支护设计参数的确定;合理运用中间主应力的Drucker-Prager准则,较Mohr-Coulumb准则更能保证工程实践的安全性。研究结果可为巷道围岩相关理论研究和工程设计提供借鉴。

     

    Abstract: With consideration to rheological behavior, surrounding rock mass in roadway is divided into elastic zone, plastic hardening zone, plastic softening zone and plastic flowing zone.And the paper derives the stress, displacement and radius of each area based on the Drucker-Prager criterion by considering the influences of pre-peak strain hardening, post-peak strain softening, dilatancy property and the intermediate principal stress.Then discusses the influences of surrounding rock deforming on the basis of a case study.Study results show that both the intermediate principal stress and surrounding rock’s rheology have great impact on plastic zone and displacement and the former has a significant interval effect.It can control roadway deforming and plastic zone extending effictively to enhace the intermediate principal stress in a specific range.In theoretical research and engineering practice, ignoring the influences of surrounding rock’s rheological behavior is actually overrating the feature of surrounding rock.It is bad for long-term stability evaluation and supporting quantitative design of surrounding rock.And in consideration of the intermediate principal stress,the Drucker-Prager criterion can ensure the safety of engineering better than the Mohr-Coulumb criterion to some extent.This study can provide some theoretical reference for related theoretical research and engineering design in roadway.

     

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