岩体结构非平衡演化的有效应力原理及长期稳定性分析

发布时间：2018-01-14 01:05

本文关键词：岩体结构非平衡演化的有效应力原理及长期稳定性分析　出处：《力学学报》2015年04期 　论文类型：期刊论文

【摘要】：开挖卸荷后的天然岩体往往处于非平衡演化状态,将直接影响岩体工程结构的正常运行、长期稳定和安全.时效变形和损伤演化是岩体结构非平衡演化的核心.在赖斯(Rice)内变量热力学理论框架下,提出了岩体结构非平衡演化的有效应力原理,指出有效应力是总应力中能有效驱动结构演化的部分.将内变量率形式的非弹性应变率方程和能量耗散率函数表示为有效应力形式,并提出非弹性余能概念.给定具体的余能密度函数和内变量演化方程,得到了考虑损伤的内变量黏塑性应变率方程.通过相似材料加卸载蠕变试验结果进行参数辨识,并分别计算了内变量率形式和有效应力形式的黏塑性应变率、能量耗散率和非弹性余能,并对其进行比较分析.结果表明:在过渡蠕变和稳态蠕变阶段两种形式的方程计算的黏塑性应变率几乎相等,但在加速蠕变阶段两者相差较大;非弹性余能和能量耗散率全域积分分别从驱动结构非平衡演化的内在潜力和实际效果的角度表征了结构的非平衡演化状态和演化趋势,能量耗散率积分更合适用于评价岩体工程结构的长期稳定性.最后以深埋地下洞室作为工程算例,并对其长期稳定性进行分析.
[Abstract]:The natural rock mass after excavation and unloading is often in the state of non-equilibrium evolution, which will directly affect the normal operation of rock mass engineering structure. Long-term stability and safety. Aging deformation and damage evolution are the core of non-equilibrium evolution of rock mass structure. The effective stress principle of non-equilibrium evolution of rock mass structure is proposed. It is pointed out that the effective stress is the part of the total stress that can effectively drive the evolution of the structure. The inelastic strain rate equation and the energy dissipation rate function in the form of internal variable rate are expressed as the effective stress forms. The concept of inelastic complementary energy is proposed. Given the specific complementary energy density function and the evolution equation of internal variables. The viscoplastic strain rate equation of internal variable considering damage is obtained, and the viscoplastic strain rate in the form of internal variable rate and effective stress is calculated, respectively, by using the loading and unloading creep test results of similar materials. The energy dissipation rate and the inelastic complementary energy are compared and analyzed. The results show that the viscoplastic strain rates calculated by the equations in the transition creep stage and the steady creep stage are almost equal. But there is a big difference between them in the accelerated creep stage. The global integration of inelastic complementary energy and energy dissipation rate represents the non-equilibrium evolution state and evolution trend of the structure from the perspective of the intrinsic potential and actual effect of the non-equilibrium evolution of the driving structure, respectively. The energy dissipation rate integral is more suitable to evaluate the long-term stability of rock mass engineering structure. Finally, the deep buried underground cavern is taken as an engineering example and its long-term stability is analyzed.
【作者单位】：清华大学水沙科学与水利水电工程国家重点实验室;
【基金】：国家自然科学基金项目(11172150,51279086) 水沙科学与水利水电工程国家重点实验室科研项目(2013-KY-2) 教育部新世纪优秀人才支持计划(NCET-13-0323)资助)~~
【分类号】：TU45
【正文快照】： 引言自然条件下的岩体结构经过漫长的地质演化过程而处于天然的平衡状态,即预先存在平衡[1].剧烈的工程扰动,例如开挖、蓄水等,破坏了这种平衡使得扰动岩体出现与时间有关的应力和变形重分布过程,该过程可称为非平衡演化过程,将直接影响岩体工程结构正常运行、长期稳定和安全[

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