孔隙液体相态对饱和砂土力学特性影响试验  

Triaxial Test on Mechanical Properties of Saturated Sand Influenced by Pore Liquid Phase State

作　　者：季伟伟 杨庆[1] 孔纲强[2] 杨钢[1] 徐洁[2] JI Weiwei;YANG Qing;KONG Gangqiang;YANG Gang;XU Jie(State Key Laboratory of Coastal and Offshore Engineering,Dalian University of Technology,Dalian 116024,China;Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering,Hohai University,Nanjing 210098,China)

机构地区：[1]大连理工大学海岸和近海工程国家重点实验室,辽宁大连116024 [2]河海大学岩土力学与堤坝工程教育部重点实验室,江苏南京210098

出　　处：《防灾减灾工程学报》2023年第4期871-877,共7页Journal of Disaster Prevention and Mitigation Engineering

基　　金：海岸和近海工程国家重点实验室开放基金重点项目(LP21V2)资助。

摘　　要：天然气水合物开采过程中,水合物分解会引起沉积物孔隙液体相态变化,降低海床的安全稳定性。基于低温、高压三轴试验仪,以粉细砂土为骨架,制备含冰/不含冰甲烷水合物沉积物试样以及饱和砂土试样,开展三轴压缩试验,分析饱和砂土中孔隙液体处于不同相态条件下试样的应力-应变和强度特性,比较在剪切过程中孔隙水压力以及切线模量等参数变化。试验结果表明:含冰/不含冰甲烷水合物沉积物以及饱和砂土的强度比值约为2.6∶1.7∶1,且均表现为应变硬化;含冰水合物沉积物的结构性较其余两者相对更强,即初始切线模量值相对更高;但是在遭受剪切后结构均破坏,切线模量迅速降低。The decomposition of hydrate will cause changes in the pore liquid phase of the sediments during the process of natural gas hydrate mining,which reduces the safety and stability of the seabed.Based on the low temperature and high pressure triaxial test apparatus,using silt fine sand as the skele-ton,the ice-containing/ice-free methane hydrate sediment samples and saturated sand samples were prepared,and the triaxial compression tests were carried out.The stress-strain and strength character-istics of the sample with different pore liquid phases were analyzed.The changes in parameters such as pore water pressure and tangent modulus during the shearing process were compared.The test results show that the strength ratio between ice-containing/ice-free methane hydrate sediments and saturated sand is about 2.6:1.7:1,and all three samples show strain hardening;the structure of the ice hydrate sediment is stronger than the others,which means a high initial tangent modulus of the ice hydrate sed-iment;but its tangent modulus decreases rapidly when the structure is destroyed after shearing.

关 键 词：相态变化 砂土 力学特性 三轴试验 

分 类 号：TU398.9[建筑科学—结构工程]