Multi-factor sensitivity analysis on the stability of submarine hydrate-bearing slope

Liang Kong; Zhen-fei Zhang; Qing-meng Yuan; Qian-yong Liang; Yao-hong Shi; Jin-qing Lin

doi:10.31035/cg2018051

2018 Vol. 1, No. 3

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Article navigation > China Geology > 2018 > 1(3): 367-373

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Liang Kong, Zhen-fei Zhang, Qing-meng Yuan, Qian-yong Liang, Yao-hong Shi, Jin-qing Lin, 2018. Multi-factor sensitivity analysis on the stability of submarine hydrate-bearing slope, China Geology, 1, 367-373. doi: 10.31035/cg2018051

Citation:

Multi-factor sensitivity analysis on the stability of submarine hydrate-bearing slope

a.
School of Science, Qingdao University of Technology, Qingdao 266033, China
b.
Guangzhou Marine Geological Survey, Guangzhou 510760, China

More Information

Corresponding author: qdkongliang@163.com (Liang Kong)

Received Date: 29 July 2018

Revised Date: 09 August 2018

Accepted Date: 29 August 2018

Available Online: 29 August 2018

Publish Date: 25 November 2018

Abstract

Abstract

There are many factors affecting the instability of the submarine hydrate-bearing slope (SHBS), and the interaction with hydrate is very complicated. In this paper, the mechanical mechanism of the static liquefaction and instability of submarine slope caused by the dissociation of natural gas hydrate (NGH) resulting in the rapid increase of pore pressure of gas hydrate-bearing sediments (GHBS) and the decrease of effective stress are analyzed based on the time series and type of SHBS. Then, taking the typical submarine slope in the northern South China Sea as an example, four important factors affecting the stability of SHBS are selected, such as the degree of hydrate dissociation, the depth of hydrate burial, the thickness of hydrate, and the depth of seawater. According to the principle of orthogonal method, 25 orthogonal test schemes with 4 factors and 5 levels are designed and the safety factors of submarine slope stability of each scheme are calculated by using the strength reduction finite element method. By means of the orthogonal design range analysis and the variance analysis, sensitivity of influential factors on stability of SHBS are obtained. The results show that the degree of hydrate dissociation is the most sensitive, followed by hydrate burial depth, the thickness of hydrate and the depth of seawater. Finally, the concept of gas hydrate critical burial depth is put forward according to the influence law of gas hydrate burial depth, and the numerical simulation for specific submarine slope is carried out, which indicates the existence of critical burial depth.
- Submarine slope /
- Gas hydrate /
- Strength reduction finite element method /
- Instability mechanism /
- Sensitivity analysis /
- Critical burial depth

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References

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