| 引用本文: | 胡田飞,刘建坤,房建宏,徐安花,常丹.冻融循环下含水率对粉质黏土力学性质影响试验[J].哈尔滨工业大学学报,2017,49(12):123.DOI:10.11918/j.issn.0367-6234.201702062 |
| HU Tianfei,LIU Jiankun,FANG Jianhong,XU Anhua,CHANG Dan.Experimental study on the effect of moisture content on mechanical properties of silty clay subjected to freeze-thaw cycling[J].Journal of Harbin Institute of Technology,2017,49(12):123.DOI:10.11918/j.issn.0367-6234.201702062 |
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| 冻融循环下含水率对粉质黏土力学性质影响试验 |
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胡田飞1,2,刘建坤1,2,房建宏2,徐安花2,常丹1,2
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(1.北京交通大学 土木建筑工程学院,北京100044; 2.青海省交通科学研究院 多年冻土地区公路建设与养护技术交通行业重点实验室青海研究观测基地,西宁810000)
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| 摘要: |
| 为研究初始含水率对土体力学性质冻融循环效应的影响规律，以青藏高原粉质黏土为对象，进行不同含水率、围压及冻融次数条件下的三轴试验.结果表明：冻融循环使得不同初始含水率试样的应力-应变曲线趋于接近，低含水率试样的力学性质表现为劣化，在一定范围内，含水率越高，劣化效果越显著；当含水率增加至某一值后，一般为接近塑限时，冻融循环效应则表现为强化; 封闭条件下土体冻融循环中的水分迁移会引起含水率的增减分区分布，且初始含水率越高，水分迁移量越大; 土体破坏强度随含水率的增加以非线性规律减小，因此试样冻融循环后含水率增大区和减小区的强度变化幅度不同，会引起破坏强度增大、减小及不变等3种不同的变化趋势; 冻融循环下土体力学性质会受到干密度、水分重分布及土体结构改变等多方面的影响，初始含水率和冻融次数不同，占主导地位的因素也不同，冻融循环效应就相应地呈现出多样化特征.
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| 关键词: 冻融循环 含水率 粉质黏土 破坏强度 非线性 抗剪强度指标 |
| DOI：10.11918/j.issn.0367-6234.201702062 |
| 分类号:U416 |
| 文献标识码:A |
| 基金项目:交通运输部应用基础研究计划(重点平台)项目(2014319363200)；国家自然科学基金(7,1) |
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| Experimental study on the effect of moisture content on mechanical properties of silty clay subjected to freeze-thaw cycling |
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HU Tianfei1,2,LIU Jiankun1,2,FANG Jianhong2,XU Anhua2,CHANG Dan1,2
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(1.School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China; 2.Transportation Industry Laboratory of Highway Construction and Maintenance Technology in Permafrost Regions-Qinghai Research Observation Base, Qinghai Research Institute of Transportation, Xining 810000, China)
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| Abstract: |
| To study the effect of moisture content on mechanical properties of soil subjected to freeze-thaw cycling, a series of triaxial tests were conducted under different confining pressures for samples which were made of silty clay from Qinghai-Tibet Plateau with different original moisture contents and had experienced various freeze-thaw cycles. The results show that the stress-strain curves of samples with different moisture contents tend to be similar after freeze-thaw cycling. The freeze-thaw cycling effect is uncertain because of the level of original moisture content. It is deteriorating for soil with low moisture content, and the deteriorating degree aggravates with the increase of moisture content within a certain range. When the moisture content is increased to a certain value which is generally close to the plastic limit, the effect is strengthening conversely. The water migration inside samples, which are subjected to freeze-thaw cycling in a closed system, leads to the redistribution of moisture content. The higher the original moisture content is, the larger the water migration amount is. The failure strength of soil decreases with the increase of moisture content in a nonlinear law, so the change amplitude of strength in the increase zone of moisture content is different with that of the decrease zone. The failure strength of sample may exhibit different tendencies including increase, decrease or remain unchanged. The mechanical properties of soil subjected to freeze-thaw cycling are affected by the dry density, moisture redistribution and soil structure simultaneously, but the dominant factor is changeable due to different moisture contents and number of freeze-thaw cycles, which makes the freeze-thaw cycling effect on soil diversified correspondingly.
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| Key words: Freeze-thaw cycling moisture content silty clay failure strength nonlinear law shear strength index |
