冻融循环作用对青藏粘土物理 力学性质影响.pdfVIP

第24 卷 第23 期 岩石力学与工程学报 Vol.24 No.23 2005 年 12 月 Chinese Journal of Rock Mechanics and Engineering Dec. ，2005 冻融循环作用对青藏粘土物理 力学性质的影响 王大雁，马 巍，常小晓，孙志忠，冯文杰，张军伟 ( 中国科学院 寒区旱区环境与工程研究所冻土工程国家重点实验室，甘肃 兰州 730000) 摘要：为研究冻融循环作用对土物理力学性质的影响，以青藏粘土为研究对象，通过对室内制备的粘土试样在经 历 0～21 次完整冻融循环过程后，进行不同围压下三轴压缩试验，研究经多次冻融作用后，高度、试样含水量、 应力–应变行为、破坏强度、弹性模量、抗剪强度指标等物理力学性质的变化。试验结果表明：冻融过程是使土 体从不稳定态向动态稳定态的发展过程，反复的冻融循环改变了土体的性状，使得土体向新的动态稳定平衡状态 发展。 关键词：土力学；冻融循环；青藏粘土；三轴试验；破坏强度 中图分类号：TU 411 文献标识码：A 文章编号：1000 –6915(2005)23 –4313 –07 PHYSICO-MECHANICAL PROPERTIES CHANGES OF QINGHAI—TIBET CLAY DUE TO CYCLIC FREEZING AND THAWING WANG Da-yan ，MA Wei ，CHANG Xiao-xiao，SUN Zhi-zhong，FENG Wen-jie ，ZHANG Jun-wei (State Key Laboratory of Frozen Soil Engineering ，Cold and Arid Regions Environmental and Engineering Research Institute ， Chinese Academy of Sciences，Lanzhou 730000，China) Abstract ：A fine-grained clay was compacted in the laboratory and was thereafter exposed to a maximum of 21 closed-system freezing and thawing cycles. The sample height，water content ，stress-strain behavior，failure strength，elastic modulus，cohesion and internal friction angle were measured in unfrozen soil as well as in thawed soil. The results show that the physio-mechanical characteristic of investigated soils changed after freezing and thawing. The height of studied sample increased and water content decreased before 7 freezing and thawing cycles and kept invariable after 7 freezing-thawing. The curves style of stress-strain behavior were not be affected by freeze-thaw process ；but the elastic modulus and failure strength were heavily influenced by the number