长江科学院院报 ›› 2020, Vol. 37 ›› Issue (12): 139-145.DOI: 10.11988/ckyyb.20190935

• 岩土工程 • 上一篇    下一篇

含水合物泥质粉细砂三轴试验及本构模型

杨周洁1, 周家作2, 陈强3,4, 万义钊3,4, 韦昌富1,2, 孟祥传1   

  1. 1.桂林理工大学 广西岩土力学重点实验室,广西 桂林 541004;
    2.中国科学院武汉岩土力学研究所 岩土力学与工程国家重点实验室, 武汉 430071;
    3.青岛海洋地质研究所 自然资源部天然气水合物重点实验室,山东 青岛 266071;
    4.青岛海洋地质研究所 海洋国家实验室海洋矿产资源评价与探测技术功能实验室,山东 青岛 266071
  • 收稿日期:2019-08-01 修回日期:2019-12-30 出版日期:2020-12-01 发布日期:2020-12-28
  • 通讯作者: 周家作(1987-),男,四川达州人,助理研究员,博士, 主要从事冻土与天然气水合物沉积物方面的研究。E-mail: jzzhou@whrsm.ac.cn
  • 作者简介:杨周洁(1994-),男,浙江绍兴人,硕士研究生,主要从事含天然气水合物沉积物方面的研究。E-mail:yzhoujie1223@163.com
  • 基金资助:
    国家自然科学基金项目(41602312,41572293);国家专项海洋地质调查二级项目(DD20190231)

Triaxial Test and Constitutive Model for Hydrate-bearing Clayey Sand

YANG Zhou-jie1, ZHOU Jia-zuo2, CHEN Qiang3,4, WAN Yi-zhao3,4, WEI Chang-fu1,2, MENG Xiang-chuan1   

  1. 1. Guangxi Key Laboratory of Geomechanics and Geotechnical Engineering, Guilin University of Technology,Guilin 541004, China;
    2. State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute ofRock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China;
    3. Key Laboratory ofNatural Gas Hydrate of Ministry of Natural Resources, Qingdao Institute of Marine Geology, Qingdao 266071, China;
    4. Laboratory of Assessment and Prospecting Technologies for Marine Mineral Resources under Qingdao National Laboratory for Marine Science and Technology, Qingdao Institute of Marine Geology, Qingdao 266071, China
  • Received:2019-08-01 Revised:2019-12-30 Online:2020-12-01 Published:2020-12-28

摘要: 为了得到不同有效围压和水合物饱和度对含水合物沉积物强度和刚度的影响规律,并得出相应数学表达式,以南海北部沉积物土样级配作为参考,配制人工泥质粉细砂,利用自主研发的含水合物沉积物三轴试验机,制备不同饱和度的含CO2水合物沉积物,在1, 2, 4 MPa有效围压下等向固结并进行三轴剪切试验。由于围压能自动根据气压的变化而变化,所以在水合物生成过程中有气体消耗但有效围压保持不变。试验结果表明:初始弹性模量随水合物饱和度的增加而增加,与有效围压无关;初始泊松比随着有效围压增加而减小,而随水合物饱和度的增加而增加;黏聚力随水合物饱和度的增加而增加,而内摩擦角与水合物饱和度无关。在邓肯-张模型的基础上,引入参数水合物饱和度,建立了含水合物沉积物的非线性弹性本构模型。最后,用试验数据对模型进行了验证,其结果符合较好。

关键词: 含水合物沉积物, 泥质粉细砂, 三轴试验, 力学行为, 本构模型

Abstract: Triaxial shear tests were conducted on self-prepared hydrate-bearing sediments to obtain the influences of effective confining pressure and saturation on the strength and rigidness of hydrate-bearing sediments. The test specimens were made from artificial clayey fine sand in reference to the particle size distribution of sediment in the north part of South China Sea. CO2 hydrate-bearing sediments with different saturations were prepared by a self-developed triaxial test machine, and the triaxial shear tests were carried out under the effective confining pressure of 1 MPa, 2 MPa, and 4 MPa. As confining pressure changes automatically with gas pressure, the effective confining pressure remained unchanged during the formation of hydrate when gas was consumed. The experimental results reveal that the initial elastic modulus increased with the rising of hydrate saturation, while independent of the effective confining pressure. The initial Poisson ratio decreased with the increase of effective confining pressure while grew with the rising of hydrate saturation. The strength index cohesive force increased with the increase of hydrate saturation, while the internal friction angle was independent of hydrate saturation. In addition, the nonlinear elastic constitutive model for hydrate-bearing sediment was established by introducing a parameter hydrate saturation based on Duncan-Chang’s model, and the proposed model was validated by test data.

Key words: hydrate-bearing sediments, clayey sand, triaxial test, mechanical behavior, constitutive model

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