不同排水条件间歇循环荷载作用下软黏土变形特性试验研究  

Experimental study on deformation behaviors of saturated soft clay under intermittent cyclic loading with various drained conditions

作　　者：黄珏皓 徐临风 卢渊 晏文隆 陈健[1,2] 付晓东 HUANG Juehao;XU Linfeng;LU Yuan;YAN Wenlong;CHEN Jian;FU Xiaodong(State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071,China;University of Chinese Academy of Sciences,Beijing 100049,China;Faculty of Land Resources Engineering,Kunming University of Science and Technology,Kunming 650093,China;School of Civil Engineering,Chongqing University,Chongqing 400045,China;Power Transformer Engineering Research Institute,China Electric Power Research Institute,Beijing 102401,China)

机构地区：[1]中国科学院武汉岩土力学研究所,岩土力学与工程国家重点实验室,湖北武汉430071 [2]中国科学院大学,北京100049 [3]昆明理工大学国土资源工程学院,云南昆明650093 [4]重庆大学土木工程学院,重庆400045 [5]中国电力科学研究院有限公司输变电工程研究所,北京102401

出　　处：《岩土工程学报》2024年第S02期92-96,共5页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金面上项目(52079135);中国科学院青年创新促进会项目(2021325)。

摘　　要：以往研究中通常采用间歇加载循环三轴试验来研究交通荷载作用下软黏土的变形特性。但交通荷载引起的土单元应力场中,水平应力和轴向应力循环变化。而且在循环加载阶段和间歇停振阶段,土体孔隙水均可以排出。因此,通过对软黏土开展两类循环三轴试验,即不排水和部分排水条件下的间歇加载循环三轴试验,研究了间歇循环荷载作用下软黏土变形特性,分析了循环围压和排水条件对软黏土累积轴向变形的影响。试验结果表明,累积轴向应变受循环围压和排水条件影响显著。累积应变增量随加载阶段的增加而减小,但不同循环围压下应变增量的衰减程度不同;在部分排水条件下,应变增量随循环围压增加而增大,而在不排水条件下则下降;另一方面,相较于不排水条件,部分排水条件下应变增量的衰减程度更为显著;同时,不同试验条件下应变增量的差异性在第一个加载阶段中较为明显,而在后续加载阶段中则可以忽略。基于上述试验结果,提出了一个考虑循环围压和排水条件影响的预测间歇循环荷载作用下软黏土累积应变的表达式,预测结果与实测值较为吻合。上述研究成果有助于加深对间歇循环荷载作用下软黏土力学性质的认识。In the previous studies,the cyclic triaxial tests under intermittent cyclic loading are used to study the deformation characteristics of soft clay under traffic loads.Both confining pressure and deviator stress vary cyclically in the stress field under traffic loads.The pore water in the soil can be discharged during cyclic loading and intermittent periods.Therefore,two types of cyclic triaxial tests are performed on soft clay,i.e.,cyclic triaxial tests with intermittent cyclic loading are undrained and partially drained conditions.The deformation characteristics of soft clay under intermittent cyclic loading were studied,and the effects of cyclic confining pressure and drained conditions on the accumulated axial strain are analyzed.The test results indicate that the accumulated axial strain is significantly affected by the cyclic confining pressure and drained conditions.The strain increment decreases with the increasing loading stage,but the attenuation degree of strain increment varies under different cyclic confining pressures.The strain increment increases as the cyclic confining pressure increases under partially drained conditions,while decreases under undrained conditions.Besides,compared to that under undrained conditions,the attenuation degree of strain increment is more significant under partially drained conditions.Meanwhile,the difference in the strain increment under different test conditions is more pronounced at the first loading stage,and can be ignored at subsequent loading stages.Based on that,a formula for predicting the accumulated axial strain of soft clay under intermittent cyclic loading considering the influences of cyclic confining pressure and drained conditions is proposed,and the predicted results are in good agreement with the measured values.The above research results contribute to a deeper understanding of the mechanical properties of soft clay under intermittent cyclic loading.

关 键 词：间歇循环荷载 软黏土 应变增量 循环围压 排水条件 

分 类 号：TU442[建筑科学—岩土工程]