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Journal of Zhejiang University SCIENCE A
ISSN 1673-565X(Print), 1862-1775(Online), Monthly
2025 Vol.26 No.2 P.151-165
A novel shear damage model of the shear deformation and failure process of gas hydrate-bearing sediments
Abstract: A novel shear damage model based on homogenization theory and a modified Mohr-Coulomb criterion is proposed to predict the full deformation process of gas hydrate-bearing sediments (GHBSs) during shearing by analyzing micro-mechanisms of shear deformation and failure characteristics. Then, the physical significance of the model’s parameters is explored. Finally, the damage evolution and shear stress partition inside GHBSs during the shearing process are analyzed in detail. The results show that model parameters have clear physical meaning, and the shear damage model is capable of reflecting the nonlinear deformation and strain softening characteristics of GHBSs due to its ability to better describe the damage evolution and shear stress partition mechanisms inside GHBSs during the shearing process. Comparisons of experimental and theoretical results show that the global performance of the novel shear damage model is satisfactory. The model is expected to be widely adopted to analyze submarine landslide instability due to hydrate dissociation.
Key words: Gas hydrate-bearing sediments (GHBSs); Shear damage model; Homogenization theory; Modified Mohr-Coulomb (MC) criterion; Damage evolution
机构：1中国石油大学(华东)，储运与建筑工程学院，中国青岛，266580；2武汉大学，水工程科学研究院，中国武汉，430072
目的：水合物开采造成的水合物饱和度降低严重影响了水合物储层的宏观力学响应，进而引起储层失稳和海底滑坡等灾害。基于水合物沉积物的微观变形机制，本文旨在提出可以考虑水合物含量影响的水合物沉积物的剪切损伤本构模型。
创新点：1.基于均匀化理论和修正摩尔-库伦准则，提出了水合物沉积物的剪切损伤本构模型；2.采用该模型研究了模型参数的物理意义和水合物沉积物剪切变形破坏的细观机制。
方法：1.通过分析水合物沉积物剪切变形的微观机制，基于均匀化理论建立水合物沉积物的剪应力分配方程；2.基于统计损伤力学和考虑水合物饱和度的修正摩尔-库仑强度准则，建立水合物沉积物的剪切损伤本构模型；3.将理论预测结果与试验结果进行对比，验证所提模型的可行性和有效性。
结论：1.该剪切损伤模型通过引入损伤力学，可以预测水合物沉积物的变形破坏特征，特别是水合物胶结破坏引起的应变软化特征；实验结果与理论结果比较表明，该剪切损伤模型能够较好地模拟水合物沉积物的剪切应力-剪切位移曲线全过程。2.分布参数F0主要反映水合物沉积物的统计平均宏观强度，而分布参数m主要影响水合物沉积物剪切应力曲线的峰后形态。3.本研究提出的剪切损伤模型能够更好地描述剪切过程中水合物沉积物内部的损伤演化和剪应力分配机制，揭示了细观损伤演化、细观应力分配与宏观力学行为之间的跨尺度关系，因此该方法能更准确地反映含天然气水合物沉积物的非线性变形和应变软化特征。
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DOI:
10.1631/jzus.A2300373
CLC number:
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On-line Access:
2025-02-28
Received:
2023-07-21
Revision Accepted:
2023-12-02
Crosschecked:
2025-02-28