Experimental investigation on the mechanical properties of methane hydrate-bearing sand formed with rounded particles
Experimental investigation on the mechanical properties of methane hydrate-bearing sand formed with rounded particles
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DOI：
10.1016/j.jngse.2017.05.008
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发表时间：
2017-09-01
影响因子：
--
通讯作者：
Yoshimoto, Norimasa
中科院分区：
文献类型：
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作者：
Kajiyama, Shintaro;Wu, Yang;Yoshimoto, Norimasa
对圆形玻璃微珠和天然砂形成的甲烷水合物砂进行了一系列的三轴压缩试验，以考察其力学性能。从颗粒尺度的角度解释了颗粒特性对含甲烷水合物砂岩的力学响应的影响，即颗粒间粘结力的施加和脱粘机理。与天然砂相比，甲烷水合物玻璃微珠具有相似的初始刚度，并在较小的轴向应变下迅速达到峰值剪切强度。含甲烷水合物玻璃微珠具有明显的峰后应变软化行为，与含甲烷水合物天然砂的峰后应变软化倾向不同。这归因于水合物质量几乎同时从直剪切层内表面光滑的玻璃微珠上剥落。含甲烷水合物玻璃微珠剪切强度提高的主要来源是内聚力，而含甲烷水合物天然砂的抗剪强度受内聚力和内摩擦角共同控制。与含甲烷水合物的天然砂的剪切强度差随有效围压的升高而增大的趋势相反，含甲烷水合物的玻璃微珠在相对较低的压力下对剪切强度差有较强的粘结力影响，但在较高的压力下这种影响减弱。(C)2017爱思唯尔B.V.保留所有权利。
A series of triaxial compression tests were performed on the methane hydrate-bearing sands formed with rounded glass beads and natural sands to,examine their mechanical properties. The effect of particle characteristics on the mechanical response of methane hydrate-bearing sands with regard to the exertion of bonding force and de-bond mechanism between grains is explained from the grain-scale viewpoint. In comparison with the natural sand, methane hydrate-bearing glass beads owns a similar initial stiffness and rapidly attains the peak shear strength at a smaller axial strain. The obvious post-peak strain-softening behaviour of methane hydrate-bearing glass beads which differs from the tender post-peak strain-softening tendency of methane hydrate-bearing natural sand is observed. It is attributed to almost simultaneous exfoliation of hydrate mass from the glass beads with smooth surface within the straightly sheared layers. The substantial resource of shear strength enhancement for methane hydrate-bearing glass beads is the cohesion but the shear strength of methane hydrate-bearing natural sand was jointly governed by the cohesion and angle of internal friction. In contrast to the increasing tendency of difference of shear strength with the level of effective confining pressure for methane hydrate-bearing natural sand, the methane hydrate-bearing glass beads exerts a stronger effect of bonding force on the difference of shear strength at relatively lower pressures but this effect decreases at higher pressures. (C) 2017 Elsevier B.V. All rights reserved.