| 朱洵,蔡正银,黄英豪,张晨,郭万里.湿干冻融耦合循环及干密度对膨胀土力学特性影响的试验研究[J].水利学报,2020,51(3):286-294 |
| 湿干冻融耦合循环及干密度对膨胀土力学特性影响的试验研究 |
| Research on mechanical properties of expansive soils under cyclic action of coupling wetting-drying and freeze-thaw and density |
| 投稿时间：2019-05-23 |
| DOI：10.13243/j.cnki.slxb.20190362 |
| 中文关键词: 膨胀土 湿干冻融耦合循环 干密度 体积变形特征 弹性模量 有效抗剪强度指标 |
| 英文关键词: expansive soil coupling wetting-drying and freeze-thaw dry density volume deformation elastic modulus effective shear strength index |
| 基金项目:国家重点研发计划项目（2017YFC0405100）；国家自然科学基金项目（51879166，51709185）；中央级公益性科研院所基金基本科研业务费项目（Y319006，Y320010）；中国博士后科学基金项目（2018M640500） |
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| 中文摘要: |
| 为探讨北疆高寒地区恶劣气候对不同干密度下渠基膨胀土力学特性的影响，利用自行设计的单向环境边界加载装置，设计了满足现场渠基膨胀土压实程度、符合北疆地区实际气候条件的三轴压缩试验，研究了湿干冻融耦合循环次数及干密度对膨胀土应力-应变关系、孔隙水压力、有效抗剪强度指标等力学特性的影响。试验结果表明：低围压（σ3=100 kPa）下试样应力-应变曲线的应变硬化程度随干密度的增加逐渐降低；湿干冻融耦合循环作用下干密度较高试样的体积整体呈增大趋势，而干密度较低试样则呈逐渐降低；耦合循环次数的增加促进了试样在不排水条件下偏应力向孔隙水压力的转化，且不同干密度试样的内部土骨架结构强度随循环次数增加存在相互转化现象；耦合循环作用下高干密度试样弹性模量的衰减速率明显低于干密度较低情况；干密度的增加抑制了试样有效黏聚力的衰减，但对有效内摩擦角的衰减却起到加剧效果。 |
| 英文摘要: |
| In order to explore the influence of the harsh climate in the alpine region of northern Xinjiang on the mechanical properties of the expansive soil under different dry densities, the self-designed one-way environmental boundary loading device was designed to meet the compaction degree of the expansive soil on the site and meet the actual situation in northern Xinjiang. The triaxial compression test of climatic conditions studied the effects of the number of wet-dry freeze-thaw coupling cycles and dry density on the stress-strain relationship, pore water pressure and effective shear strength of expansive soil. The test results show that the strain hardening degree of the stress-strain curve of the sample decreases with the increase of dry density under low confining pressure (σ3=100 kPa); the overall volume of the sample with higher dry density under the action of wet-dry freeze-thaw coupling cycle The sample shows an increasing trend, while the sample with lower dry density decreases gradually. The increase of the number of cycles promotes the conversion of the deviatoric stress to the pore water pressure under undrained conditions,and the internal soil skeleton structure of different dry density samples. The strength increases with the increase of the number of cycles. The decay rate of the elastic modulus of the high dry density sample is significantly lower than that of the dry density. The increase of the dry density inhibits the attenuation of the effective cohesion of the sample,but Attenuating the effective internal friction angle. |
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