考虑剪胀效应的深埋圆形隧道围岩应变软化弹塑性解

发布时间：2019-05-22 22:24

【摘要】：隧道围岩非线性体积膨胀影响施工安全,如何正确评价隧道围岩塑性区域内扩容机制非常重要。多数研究从理论上推导深埋圆形隧洞应变软化围岩应力-应变场时仅采用恒定或线性变化剪胀模型,针对此不足,提出了一种基于有限差分法的分析方法,能够合理地考虑围岩非线性剪胀效应及其应变软化特性。利用已有的研究成果,验证了该方法的合理性,并进一步探讨了不同质量石灰岩与支护压力下剪胀系数在围岩塑性区域内的影响因素,比较了恒定与非线性变化剪胀模型下围岩变形的不同。结果表明:对于地质强度指标(GSI)较小、质量较差的岩体,塑性区域内主要由围压控制剪胀效应程度;恒定与非线性变化剪胀模型下围岩洞壁变形差别显著。
[Abstract]:The nonlinear volume expansion of tunnel surrounding rock affects the construction safety, so it is very important to correctly evaluate the expansion mechanism in the plastic area of tunnel surrounding rock. In most studies, the stress-strain field of strain softened surrounding rock of deep buried circular tunnel is deduced theoretically by using only constant or linear shear expansion model. In order to solve this problem, an analysis method based on finite difference method is proposed. The nonlinear shear expansion effect and strain softening characteristics of surrounding rock can be considered reasonably. Based on the existing research results, the rationality of the method is verified, and the influencing factors of shear expansion coefficient under different mass limestone and support pressure in the plastic area of surrounding rock are further discussed. The deformation of surrounding rock under constant and nonlinear shear expansion model is compared. The results show that for the rock mass with small geological strength index (GSI) and poor quality, the degree of shear expansion effect is mainly controlled by confining pressure in the plastic region, and the deformation of surrounding rock wall under constant and nonlinear shear expansion model is significantly different.
【作者单位】：华中科技大学岩土与地下工程研究所;
【基金】：新世纪优秀人才支持计划资助项目(No.NCET 06 619)
【分类号】：U451.2

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