Numerical study on the stratum's responses due to natural gas hydrate dissociation

ABSTRACT

Natural gas hydrate (NGH) dissociation can cause many kinds of potential hazards. Dimensional analysis is used first to obtain the controlling factors for NGH dissociation-induced stratum's responses. And then the effects of the controlling factors on the deformation and stress distribution have then been numerically investigated. A simplified critical condition for judging the instability of gentle inclined stratum after NGH dissociation was proposed. It is shown that the maximum settlement is located near the upper part of the slide body while the soil uplifts near the lower part. The fast change of the stress and deformation is located at the interface between hydrate-bearing stratum (HBS) and over layer. The slope angle has the largest effects on the responses of the stratum. The effects of modulus and water depth on the stratum's instability are small. There is a critical extension length of dissociation zone over which landslide will occur which is determined by the strength parameters, slope angle, friction coefficient and height of the over layer.

KEYWORDS:

• Gas hydrate
• dissociation zone
• slope instability
• deformation

Additional information

Funding

This paper is supported by The National Natural Science Foundation of China [grant number 11272314], [grant number 51239010], [grant number 11102209]; Project of CAS-CNPC Strategic Alliance.