冻融循环作用下砂岩的力学特性及细观损伤本构模型研究  

Mechanical properties of sandstone under freeze-thaw cycles and studies on meso-damage constitutive model

作　　者：肖鹏 陈有亮[2] 杜曦 王苏然 XIAO Peng;CHEN Youliang;DU Xi;WANG Suran(Institute of Geotechnical Engineering,Southeast University,Nanjing 210096,China;Department of Civil Engineering,School of Environment and Architecture,University of Shanghai for Science and Technology,Shanghai 200093,China;School of Civil and Environmental Engineering,University of New South Wales,Sydney 2052,Australia;Department of Underground Architecture and Engineering,Tongji University,Shanghai 200093,China)

机构地区：[1]东南大学交通学院岩土工程研究所,江苏南京210096 [2]上海理工大学环境与建筑学院土木工程系,上海200093 [3]新南威尔士大学土木与环境工程学院,悉尼2052 [4]同济大学地下建筑与工程系,上海200093

出　　处：《岩土工程学报》2023年第4期805-815,共11页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(10872133);上海市软科学研究领域重点项目(18692106100)。

摘　　要：针对寒区岩体工程中岩石的冻融问题,选取砂岩为试样,通过进行室内冻融循环试验、扫描电子显微镜观测和三轴压缩试验对砂岩质量损失、微观结构和力学特性进行了分析。然后基于Lemaitre应变等效假设理论,通过引入能够反映岩石冻融破坏过程中的细观冻融损伤变量和力损伤变量来描述岩石材料的劣化程度及损伤演化规律,并采用连续损伤力学理论,建立了冻融与围压耦合作用下岩石的损伤演化方程及细观损伤本构模型。采用理论推导的方法得出所需的模型参数表达式,最后利用冻融岩石的三轴压缩试验数据对该模型的合理性和准确性进行了验证。将试验曲线的峰值点与模型理论曲线的峰值点进行对比,结果表明两者吻合度较好,该损伤本构模型能够较好地反映岩石三轴压缩过程的应力-应变峰值特性,验证了该模型及模型参数确定方法的合理性与可靠性。该模型拓展了岩石在冻融与围压耦合作用下的损伤模型,进一步的揭示了岩石在冻融与围压耦合作用下的损伤机制和破坏规律。To address the freeze-thaw problems of rocks in cold-zone rock engineering,the sandstone is selected as the specimen and analyzed for mass loss,microstructure and mechanical properties by conducting the cyclic indoor freeze-thaw tests,scanning electron microscope observations and triaxial compression tests.Then,based on the Lemaitre strain equivalence hypothesis theory,the meso-scale freeze-thaw damage variables and force damage variables are introduced to reflect the process of freeze-thaw damage of the rocks to describe the degree of deterioration of rock materials and the damage evolution law.Using the continuous damage mechanics theory,the damage evolution equation and the meso-scale damage constitutive model for the rocks under the coupling of freeze-thaw and cofining pressure are established.The theoretical derivation method is used to obtain the required expressions for model parameters.Finally,the rationality and accuracy of the model are verified by the triaxial compression test data of freeze-thaw of the rocks.The peak points of the test curve are compared with those of the theoretical curve by the model,and the results show that they are in good agreement.The damage constitutive model can better reflect the stress-strain peak characteristics of the rocks during triaxial compression,which verifies the rationality and reliability of the proposed model and the relevant method for determining the model parameters.This model expands the damage model for the rocks under the coupling of freeze-thaw and confining pressure and further reveals their damage mechanism and failure law.

关 键 词：冻融循环 力学特性 细观冻融损伤变量 SMP准则 损伤演化 本构模型 

分 类 号：TU411[建筑科学—岩土工程] TD313[建筑科学—土工工程]