摘要
开展荷载作用下冻土的宏-细观力学特性试验研究,对揭示冻土细观力学特性和建立宏-细观力学性质之间的联系具有重要的意义。利用重新研制的可配合医用CT进行扫描的冻土三轴仪开展了不同温度、围压条件下的饱和冻土常规三轴压缩试验研究,其中在轴向加载过程中共对试样进行了8次CT扫描。通过对CT数平均值和应力应变曲线的分析发现:当应力应变曲线表现为应变硬化时,冻土试样CT数平均值随着轴向应变的增加而线性降低;当应力应变曲线表现为应变软化时,试样CT数平均值在软化阶段加速降低。结合动态扫描过程中试样CT数平均值的变化规律,提出利用试样CT数平均值对体积破损率进行表征,建立了饱和冻土的二元介质细观本构模型,并利用试验数据对建立的本构模型进行了验证,结果表明提出的本构模型能够很好的预测冻土在常规三轴应力路径下的应力应变行为。
It is of great significance to carry out experimental researches on the macro-meso-mechanical properties of frozen soils to reveal the mechanism and the relationship between the meso-and the macro-meso-mechanical properties of frozen soils.The triaxial compression tests on the saturated frozen soils under four temperatures and four confining pressures are carried out by using the newly developed frozen soil triaxial instrument,which can cooperate with medical CT for dynamic scanning.A total of 8 CT dynamic scans are performed on the samples during the axial loading process.Through the statistical analysis of CT numbers and stress-strain curves,it is found that when the stress-strain curve is strain hardening,the average CT number of the frozen soil samples decreases linearly with the increase of the axial strain.When the stress-strain curve is strain softening,the average CT number of the frozen soil samples decreases rapidly at the softening stage.Based on the evolution laws of the average CT number of samples during the process of dynamic scanning,the breakage rate is characterized by the average CT number value,and the mesoscopic constitutive model for the saturated frozen soils is established,and the established constitutive model is verified through the test data.The results show that the proposed constitutive model can well predict the stress-strain behavior of frozen soils under the conventional triaxial stress path.
作者
张革
刘恩龙
ZHANG Ge;LIU Enlong(Key Laboratory of Geological Hazards in Three Gorges Reservoir Area,Ministry of Education,China Three Gorges University,Yichang 443002,China;College of Civil Engineering&Architecture,China Three Gorges University,Yichang 443002,China;Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China;College of Water Resources and Hydropower,Sichuan University,Chengdu 610065,China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2023年第9期1888-1896,共9页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(41771066)。
关键词
冻土
三轴压缩
CT动态扫描
细观力学特性
二元介质本构模型
frozen soil
triaxial compression
CT dynamic scanning
meso-mechanical property
binary-medium constitutive model
作者简介
张革(1991-),男,博士,讲师,主要从事冻土本构模型及数值模拟方面的研究工作。E-mail:zhangge@ctgu.edu.cn;通信作者:刘恩龙(E-mail:liuenlong@scu.edu.cn)。
