摘要
在寒区隧道工程中,冻胀的水分迁移作用加剧了隧道围岩的冻融破坏。耦合水分迁移作用的岩石本构模型对防治冻融渗漏、崩塌等隧道围岩灾害有着重要意义。基于内状态变量理论,将冻胀过程中的水分迁移量作为本征变量引入Helmholtz自由能,在热力学框架下建立了一个岩石力-热-水耦合本构模型。模型描述了温度和水分迁移对冻融后岩石损伤阈值、等向强化饱和值、等向强化速率等力学参数的影响。模拟了岩石冻融后力学性质的劣化。区别于全量经验公式,本模型以增量形式给出,为复杂应力历史条件下的数值模拟提供了便利。通过将模型模拟曲线与冻融后岩石常规三轴压缩试验曲线进行对比,初步验证模型的可靠性,为实际寒区工程的冻胀破坏预测提供参考。
In cold region tunnels, the moisture migration during the frost heave always aggravates freeze-thaw induced damage of the surrounding rock. Therefore, it is of great importance to consider the moisture migration effect on the collapse and landslide mechanisms of rocks due to freezing and thawing weathering. In this paper, the moisture migration was introduced into Helmholtz free energy as an intrinsic variable based on internal state variables theory. A general thermo-hydro-mechanical coupled constitutive model was proposed under the thermodynamic framework. The effects of temperature and moisture migration on the damage threshold, isotropic hardening saturation and isotropic hardening rate of the rock after freezing and thawing were described. The degradation of mechanical properties of rock after freezing and thawing was simulated. This model was given as an incremental form, which was convenient for the numerical modelling under complex stress loading conditions. The parameters used in the constitutive model had clear physical meanings. Finally, the simulation stress-strain curves of the constitutive model were compared with the results of triaxial compression test of the rock specimens after freeze-thaw cycles. It was proved that the proposed constitutive model could well describe the mechanical behaviors of rock after freeze-thaw cycles.
作者
王震
朱珍德
陈会官
朱姝
WANG Zhen;ZHU Zhen-de;CHEN Hui-guan;ZHU Shu(Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, Nanjing, Jiangsu 210098, China;Jiangsu Research Center for Geotechnical Engineering Technology, Hohai University, Nanjing, Jiangsu 210098, China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2019年第7期2608-2616,共9页
Rock and Soil Mechanics
基金
国家自然科学基金(No.51379065)
江苏省自然科学基金(No.BK20161508)
中央高校基本科研业务费专项资金(No.2016B42714)~~
关键词
冻融循环
热力学
内状态变量理论
水分迁移
本构关系
freeze-thaw cycles
thermodynamics
internal state variables
water migration
constitutive model
