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冰川冻土 ›› 2016, Vol. 38 ›› Issue (5): 1346-1352.doi: 10.7522/j.issn.1000-0240.2016.0158

• 寒区科学与技术 • 上一篇    下一篇

冻土的单轴抗压、抗拉强度特性试验研究

黄星1,2, 李东庆2, 明锋2, 邴慧2, 彭万巍2   

  1. 1. 四川农业大学 建筑与城乡规划学院, 四川 都江堰 611830;
    2. 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
  • 收稿日期:2016-04-18 修回日期:2016-08-20 出版日期:2016-10-25 发布日期:2017-01-22
  • 通讯作者: 李东庆,E-mail:dqli@lzb.ac.cn. E-mail:dqli@lzb.ac.cn
  • 作者简介:黄星(1988-),女,四川雅安人,2010年毕业于兰州交通大学,现为中国科学院寒区旱区环境与工程研究所在读博士研究生,主要从事冻土超声波参数与冻土物理力学性质试验研究.E-mail:hxcas7@163.com
  • 基金资助:

    国家自然科学基金项目(41271080);中国科学院前沿科学重点研究项目(QYZDY-SSW-DQC015);国家自然科学基金项目(41371090)资助

Experimental study of the compressive and tensile strengths of artificial frozen soil

HUANG Xing1,2, LI Dongqing2, MING Feng2, BING Hui2, PENG Wanwei2   

  1. 1. College of Architecture and Urban-Rural Planning, Sichuan Agricultural University, Dujiangyan 611830, Sichuan, China;
    2. State Key Laboratory of Frozen Soil Engineering, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China
  • Received:2016-04-18 Revised:2016-08-20 Online:2016-10-25 Published:2017-01-22

摘要:

在寒区工程建筑物设计中,冻土的抗压、抗拉强度是两个重要的力学指标.在负温条件下,对粉质黏土、黄土和砂土进行单轴抗压和劈裂抗拉试验,研究冻土破坏时的破坏形态、破坏机理、应力-应变曲线和拉应力与径向位移关系曲线的形式,分析单轴抗压强度和劈裂抗拉强度的差异以及这两种强度随土质特性和温度的变化规律.试验结果表明:单轴载荷作用下试样破坏后呈鼓状,且表现为应变软化型塑性破坏特征;劈裂作用下产生沿直径向试样两侧延伸的裂缝,不同土质破坏后裂缝扩展的宽度和深度不同;冻土的抗压强度与抗拉强度均与负温存在很好的线性相关性,随温度的降低而增大;在相同温度条件下,冻土的抗压强度大于其抗拉强度;对于同一种冻土,其抗压强度的温度效应比抗拉强度的温度效应显著.本试验分析结果可为寒区工程的实际应用提供参考.

关键词: 人工冻土, 室内试验, 抗压强度, 抗拉强度, 温度效应

Abstract:

The compressive strength and tensile strength of frozen soils are two important mechanical indexes for designing engineering structures in cold regions. In this paper, uniaxial compressive strength test and splitting test of silty clay, silt and sand at the temperatures below 0℃ were carried out to study the failure mode and mechanism of frozen soil, the forms of stress-strain curves and the curves of tensile stress and radial displacement, and to analyze the difference between compressive strength and tensile strength and to reveal the dependence of the two strengths on soils and temperatures. Experimental results showed that the specimen has a drum-shaped deformation under uniaxial load and all behaves as strain softening and plastic collapse characteristics. Cracks occurs along with diameter to sides under the action of splitting; the width and depth of cracks are dependent on soil behavior. There is a good linear relativity between compressive strength, as well as tensile strength, and temperature; the strengths increase with decrease in temperature. The compressive strength of frozen soil is greater than its tensile strength at the same temperature. For the same frozen soil, the temperature effect for compressive strength is stronger than that for tensile strength. The datum and results of the experiment are helpful for engineering in cold regions.

Key words: artificial frozen soil, laboratory test, compressive strength, tensile strength, temperature effect

中图分类号: 

  • P642.14