| 冻融循环对黏质粗粒土单轴抗压性能影响的试验研究 |
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| 引用本文： | 陈涛,毕贵权,陈国良,杨晗,牛富俊,穆彦虎,罗京.冻融循环对黏质粗粒土单轴抗压性能影响的试验研究[J].冰川冻土,2019,41(3):587-594. |
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| 作者姓名： | 陈涛 毕贵权 陈国良 杨晗 牛富俊 穆彦虎 罗京 |
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| 作者单位： | 兰州理工大学土木工程学院,甘肃兰州730050;中国科学院西北生态环境资源研究院冻土工程国家重点实验室,甘肃兰州730000;西藏华泰龙矿业开发有限公司,西藏拉萨,850000;中国科学院西北生态环境资源研究院冻土工程国家重点实验室,甘肃兰州,730000 |
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| 基金项目： | 中国黄金集团公司科研计划重点项目（2016ZGHJ/XZHTL-YQSC-26）；国家自然科学基金新疆联合基金重点项目（U1703244）；国家自然科学基金项目（51568043）资助 |
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| 摘 要： | 循环冻融作用下粗粒土的力学性质对于高寒地区边坡稳定性分析意义重大。以藏区某一排土场土体作为依托，开展了不同冻融循环次数后不同级配黏质粗粒土的单轴压缩试验，研究冻融循环作用对黏质粗粒土单轴抗压性能的影响。结果表明：冻融循环作用对黏质粗粒土应力-应变关系曲线性状及破坏模式有一定的影响，可使其应变呈现由脆性破坏（软化）向塑性流动（硬化）变化的规律。当提高冻融循环次数时，该类土体的弹模和抗压强度均显著减小，其中5~9次冻融循环前减小幅度较大，之后基本保持不变。单轴抗压性能的弱化与土样循环冻融过程中伴随的细颗粒团聚、大中孔隙增多、密实度下降有关。20次冻融循环后，该土质土样抗压强度、弹模最大降低幅度各自高达43%和77%。可见随着提高细砾组的含量，土样的抗压强度和弹模均呈现下降的趋势，这与该土样内粗、细土颗粒的比例及强度发挥机理密切相关。粗粒土单轴抗压破坏应变随冻融循环次数和细砾组含量的增加有一定的增加趋势。
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| 关 键 词： | 粗粒土 冻融循环 细砾组含量 单轴抗压强度 弹性模量 破坏应变 |
| 收稿时间： | 2018-04-28 |
| 修稿时间： | 2018-12-20 |
Laboratory study on effect of cyclic freeze-thaw on the uniaxial compressive properties of clayey coarse grained soils |
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| CHEN Tao,BI Guiquan,CHEN Guoliang,YANG Han,NIU Fujun,MU Yanhu,LUO Jing.Laboratory study on effect of cyclic freeze-thaw on the uniaxial compressive properties of clayey coarse grained soils[J].Journal of Glaciology and Geocryology,2019,41(3):587-594. |
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| Authors: | CHEN Tao BI Guiquan CHEN Guoliang YANG Han NIU Fujun MU Yanhu LUO Jing |
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| Institution: | 1. School of Civil Engineering, Lanzhou University of Technology, Lanzhou 730050, China;2. State Key Laboratory of Frozen Soils Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China;3. Tibet Huatailong Mining Development Co., Ltd, Lhasa 850000, China |
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| Abstract: | The mechanical property of coarse grained soil under freeze-thaw cycle is very important in slope stability analyses in cold regions. To study the effect of freeze-thaw cycles on the compressive property of clayed coarse grained soil,a series of uniaxial compression tests on clayed coarse grained soils under different freezethaw cycles and fine gravel contents have been carried out. The test results indicate that freeze-thaw cycles has an impact on stress-strain relationship characteristics and failure mode of clayed coarse grained soils,The strain changes from brittle failure(softening)to plastic flow(hardening). When the number of freeze-thaw cycles is increased,the elastic modulus and compressive strength of such soils decrease significantly. Among them,5-9 freeze-thaw cycles decreased greatly before freezing and thawing cycles,and remained unchanged after freezing and thawing cycles. After that,these maintain almost stable. The uniaxial compressive properties weaken is related to aggregation of fine particles,increase of large and medium pores,and decrease of density during freezethaw processes. After 20 cycles of freeze-thaw,the uniaxial compressive strength and the elastic modulus decreased by as much as 43% and 77%,respectively. With increase of fine gravel contents,the uniaxial compressive strength and the elastic modulus of coarse grained soil also reduces considerably. This is closely related to the proportion of coarse and fine soil particles in the soil sample and the mechanism of strength exertion. There is a minor increasing trend for the failing strain of coarse grained soil with the increase of the freeze-thaw cycles and the fine gravel contents. |
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| Keywords: | coarse grained soil freeze-thaw cycle fine gravel contents uniaxial compressive strength elastic modulus failure strain |
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