长江科学院院报 ›› 2018, Vol. 35 ›› Issue (3): 1-5.DOI: 10.11988/ckyyb.20171094

• 岩土力学试验与理论 • 上一篇    下一篇

冻融循环作用下砂岩卸荷强度特性试验及损伤特性研究

朱珍德1a,1b, 色麦尔江·麦麦提玉苏普2, 方若进1a,1b, 倪骁慧3   

  1. 1.河海大学 a.岩土力学与堤坝工程教育部重点实验室;b.江苏省岩土工程技术工程研究中心,南京 210098;
    2.喀什大学 土木工程学院,新疆 喀什 844006;
    3.嘉兴学院 建筑工程学院,浙江 嘉兴 314001
  • 收稿日期:2017-09-20 出版日期:2018-03-01 发布日期:2018-03-16
  • 作者简介:朱珍德(1964-),男,河北盐山人,教授,博士,博士生导师,主要从事岩石力学与工程方面的教学与科研工作。E-mail: zzdnj@hhu.edu.cn
  • 基金资助:
    国家自然科学基金项目(41272329,51379065);国家自然科学基金青年基金项目(51409122)

Unloading Strength Characteristics and Damage Characteristics of Sandstone under Freeze-thaw Cycles

ZHU Zhen-de1,2, Semerjan Memetyusup3, FANG Ruo-jin1,2, NI Xiao-hui4   

  1. 1.Key Laboratory of Geomechanics and Embankment Engineering of Ministry of Education, Hohai University,Nanjing 210098, China;
    2.Jiangsu Research Center for Geotechnical Engineering Technology, HohaiUniversity, Nanjing 210098, China;
    3.College of Civil Engineering, Kashgar University, Kashgar844006, China;
    4.College of Civil Engineering and Architecture, Jiaxing University, Jiaxing 314001, China
  • Received:2017-09-20 Online:2018-03-01 Published:2018-03-16

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摘要： 建立在寒区的岩土工程,其岩石的损伤劣化不仅受冻融风化作用,而且还受到开挖卸荷的影响。采用冻融循环试验和三轴卸荷试验相结合的方法,对砂岩同时受2种破坏作用的强度特性和损伤特性进行系统的分析。分析结果表明:随围压的增加,冻融循环下岩石的破坏特性由张拉破坏逐渐转变为剪切破坏特征,随着冻融次数的增加,岩样明显产生侧向膨胀,侧边中部明显向外凸出,并出现了不同级别的张裂纹、环向裂纹及许多岩粉和岩石碎块;对于三轴卸荷试验,岩样的峰值强度随着冻融次数的增加而降低;扩容应力随冻融次数增加呈指数下降关系;破坏围压与冻融次数呈二次函数关系;冻融损伤值随冻融次数增加呈线性增长,表明岩样的损伤受冻融的影响逐渐增大。研究成果可为寒区岩土工程设计和施工提供指导。

关键词: 砂岩, 冻融循环, 三轴卸荷试验, 强度特性, 损伤特性

Abstract: Geotechnical projects in cold regions suffer from both cyclic freezing-thawing and excavation unloading, giving rise to rock degradation. In this article, the strength characteristics and damage characteristics of sandstone subjected to both cyclic freezing-thawing and excavation unloading are analyzed systematically by freeze-thaw cycle test and triaxial unloading test. The results are concluded as follows: in freeze-thaw cycle test, the sandstone experienced a stage from tension failure gradually to shear failure as confining pressure rises; as the freeze-thaw cycle proceeds, the sandstone witnessed an apparent lateral expansion in the middle, with different levels of tension cracks, circular cracks, rock powder and rock fragments; while in triaxial unloading test, as freezing-thawing proceeds, the peak strength of sandstone reduces, and dilatancy stress declines in an exponential relation; destructive confining pressure is in a quadratic functional relation with cycle number; moreover, the freeze-thaw damage value increases linearly with the number of freeze-thaw cycles, indicating that the effect of cyclic freezing and thawing intensifies gradually.

Key words: sandstone, freezing and thawing cycles, triaxial unloading test, strength characteristics, damage characteristics

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