冻结黏土宏细观力学特性研究  

Study on macroscopic and microscopic mechanical properties of frozen clay

作　　者：徐安花 闫一辉 常丹 马建华 XU Anhua;YAN Yihui;CHANG Dan;MA Jianhua(Qinghai Vocational and Technical University,Xining 810003,China;School of Civil Engineering,Sun Yat-sen University,Guangzhou 510275,China;Qinghai Provincial Key Laboratory of Tibet Plateau Highway Construction Maintenance Technology,Xining 810003,China;Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai 519000,Guangdong,China)

机构地区：[1]青海职业技术大学,青海西宁810003 [2]中山大学土木工程学院,广东广州510275 [3]青海省青藏高原公路建设与养护重点实验室,青海西宁810003 [4]南方海洋科学与工程广东省实验室(珠海),广东珠海519000

出　　处：《冰川冻土》2025年第2期372-381,共10页Journal of Glaciology and Geocryology

基　　金：国家自然科学基金项目(42071078);青海省科技厅基础研究计划面上基金项目(2021-ZJ-908)资助。

摘　　要：本文针对G0613西丽高速公路共和至玉树段沿线路基冻结黏土开展了宏细观力学特性研究,为获得冻结黏土的宏观力学特性,我们通过开展不同温度、不同围压下试样的室内三轴试验,得到不同试验条件下的偏应力-应变关系曲线,揭示了不同工况下试样的抗剪强度参数及其变化规律。同时基于离散单元法,建立了冻结黏土离散元模型,通过参数标定后与室内试验结果进行对比,对加载过程中冻结黏土试样变化的细观机理进行补充分析。研究结果表明:试样在高围压下表现为应变硬化,在低围压下表现为应变软化,且产生明显的压鼓现象;随着冻结温度的降低,冻结黏土的抗剪强度显著增加,黏聚力显著增加,内摩擦角变化较小;数值模拟过程中接触力链、颗粒速度和颗粒位移等规律与室内试验结果基本吻合,同时从细观角度对试样的压鼓现象进行了解释;加载后颗粒间的胶结发生了明显破坏,并以此对损伤机理进行了分析。This study focuses on the macroscopic and microscopic mechanical properties of frozen clay in the subgrade along the G0613 Xining-Lijiang Expressway,from Gonghe to Yushu.Different temperature and con⁃fining pressure conditions were applied in indoor triaxial tests to obtain stress-strain curves under various experi⁃mental conditions,revealing the shear strength parameters and their variations for different working conditions.Additionally,a discrete element model of frozen clay was established based on the discrete element method.Af⁃ter parameter calibration,it was compared with the indoor test results to provide supplementary analysis of the micro-mechanisms of frozen clay specimen changes during loading.The research findings indicate that the speci⁃men exhibits strain hardening at high confining pressures and strain softening at low confining pressures,with ev⁃ident bulging phenomenon.As the freezing temperature decreases,the shear strength and cohesion of the frozen clay significantly increase,with minimal change in the internal friction angle.The numerical simulation pro⁃cess,including contact force chains,particle velocities,and displacements,closely matches the indoor test re⁃sults,and it provides an explanatory analysis of the bulging phenomenon at the microscale.After loading,sig⁃nificant damage occurs in the inter-particle bonding,and the damage mechanism is further analyzed.

关 键 词：冻结黏土 三轴试验 离散单元法 宏细观机理 

分 类 号：P642.14[天文地球—工程地质学] TU411[天文地球—地质矿产勘探]