摘要
针对水合物分解条件下海底黏土质斜坡破坏机制认识不足的问题,采用通气的方式模拟水合物分解后气体对海底斜坡的影响,开展了不同土体强度、水合物埋深、气体流量及分解范围组合条件下的多组模型实验.结合图像测量技术,深入分析了坡面及坡体的变形演化过程,初步揭示了模拟水合物分解条件下海底黏土质斜坡的变形破坏特征.在此基础上,采用极限平衡方法,建立了海底斜坡破坏时的临界气体压力解析式,从理论上解释了斜坡变形破坏过程中出现的临界气压值.研究结果表明:海底斜坡的变形破坏过程可分为气压累积、土体弹性压缩、斜坡破坏隆起和变形稳定4个阶段;气体临界压力计算结果与实验结果虽有偏差,但可在一定程度上反映临界压力的真实水平.研究成果为深入认识水合物分解条件下海底黏土质斜坡的变形破坏机制,发展稳定性分析理论和评价方法提供有益参考.
In view of the insufficient recognition of the failure mechanism of submarine clayey slope induced by gas hydrate dissociation, the effect of gas on submarine slope after gas hydrate dissociation was simulated by means of venting. Furthermore, multiple of experiments were carried out under different combinations of soil strength, embedment depth of gas hydrate, flow rate and dissociation zone. Combining with the image processing, the deformation and the evolutionary process of slope surface and slope body were deeply investigated. The deformation and failure characteristics of submarine clayey slope induced by hydrate dissociation were initially revealed. On this basis, a limit equilibrium method was used to establish the critical pressure analytic expression of submarine slope failure, which is theoretically explained the critical pressure value in the failure process of slope deformation. The results show that the deformation and failure processes of the submarine slope are divided into four stages: the accumulation of air pressure, the elastic compression of soil, the upheaval failure of slope, and the deformation stability of slope. Although, there is a deviation between the calculated and experimental results of gas critical pressure, it can reflect the true level of the critical pressure to some extent. The research results can provide some references for the further understanding of the deformation and failure mechanism of submarine clayey slope induced by gas hydrate dissociation, and the developments of the stability analysis theory and evaluation method.
作者
宋晓龙
赵维
年廷凯
焦厚滨
SONG Xiaolong;ZHAO Wei;NIAN Tingkai;JIAO Houbin(State Key Laboratory of Coastal and Offshore Engineering,Dalian University of Technology,Dalian 116024,Liaoning,China)
出处
《上海交通大学学报》
EI
CAS
CSCD
北大核心
2020年第1期43-51,共9页
Journal of Shanghai Jiaotong University
基金
国家重点研发计划课题(2018YFC0309203)
国家自然科学基金(51879036,51579032)资助项目
关键词
天然气水合物
海底黏土质斜坡
变形破坏机制
模型实验
gas hydrate
submarine clayey slope
deformation and failure mechanism
model experiment
