摘要
天然气水合物是一种潜在的能源资源,开采过程中,水合物的分解会造成工程和地质等安全隐患。为研究降压开采过程中多因素综合影响条件下沉积物的力学性质,在自主研发的低温高压三轴仪上进行了不同围压条件下含水合物沉积物的剪切试验。试验结合常规三轴剪切及一个试样多级加荷的方法,并加入了水合物的降压分解过程。结果表明:水合物的存在可以显著提高沉积物的抗剪强度。在降压分解过程中,含水合物沉积物试样的力学强度受到有效围压和孔隙中水合物含量的综合影响。前期试样由于孔隙压力降低导致有效围压大幅增加,试样抗剪强度增大,后期由于水合物含量的大幅降低,试样在较高有效围压下抗剪强度下降。有效围压对含水合物沉积物试样的体积应变有较大的影响,较高的有效围压会导致含水合物试样产生显著的剪缩现象。
Natural gas hydrate is anticipated to be a potential energy resource. During the mining process from methane hydrate reservoir, the decomposition of methane hydrate can cause risks threatening the safety of engineering and geology. A series of shear tests under different confining pressure conditions was carried out using self-developed low-temperature and high-pressure triaxial apparatus to investigate the mechanical properties of sediments containing methane hydrate under different conditions. The experiment combined with conventional triaxial shear method and multi-stage loading tests was focused on the hydrate decomposition process. It was found that the strength of the sediments was significantly increased due to the presence of hydrates. In the process of depressurization, the strength of sediments was found to be affected by the variations of effective confining pressure and the hydrate saturation. At the early stage, due to the decrease of pore pressure, the effective confining pressure significantly increased, and the shear strength increased as well. In the later stage, the shear strength of samples decreased under high effective confining pressure due to the decrease of hydrate content. The effective confining pressure had a great effect on volumetric strain of the hydrate sediments, and higher effective confining pressure led to obvious shear shrinkage.
作者
吴起
卢静生
李栋梁
梁德青
WU Qi;LU Jing-sheng;LI Dong-liang;LIANG De-qing(Guangzhou Institute of Energy Conversion,Chinese Academy of Sciences,Guangzhou,Guangdong 510640,China;Key Laboratory of Gas Hydrate, Chinese Academy of Sciences,Guangzhou,Guangdong 510640,China;Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development,Chinese Academy of Sciences,Guangzhou,Guangdong 510640,China;Guangzhou Center for Gas Hydrate Research,Chinese Academy of Sciences,Guangzhou,Guangdong 510640,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2018年第12期4508-4516,共9页
Rock and Soil Mechanics
基金
国家自然科学基金(No.51474197,No.51661165011)
国家重点研发计划(No.2016YFC0304002)
supported by the National Natural Science Foundation of China(51474197,51661165011)
the National Key Research and Development Plan of China(2016YFC0304002)
关键词
含水合物沉积物
降压开采
力学特性
三轴剪切试验
methane hydrate-bearing sediments
depressurization
mechanical properties
triaxial tests
