海床中的天然气水合物分解后由固体变为气体,将直接提高孔隙水压力,减小边坡内有效应力,导致边坡稳定性下降.本文以能量上限定理为理论基础,采用二维极限分析方法分析海底缓倾角边坡的滑坡机理,研究由于水合物分解形成的软弱夹层对边坡稳定性的影响.分析表明,软弱夹层的埋深和海床土体内摩擦角会对边坡的稳定性产生直接影响.由于水合物分解而产生的膨胀压力也会降低海底缓倾角边坡的稳定性.%It is indicated by some experimental and theoretical data that the disassociation of gas hydrate could directly increase pore water pressure, decrease effective stresses in the submarine slope, reduce the friction coefficient between different soil layers in slope, and in consequence the slope stability will be weakened. In this paper, a two-dimensional numerical limit analysis, incorporating the upper-bound energy method, is presented to improve the understanding of the failure mechanism of submarine low-angle slope. Based on the analysis, it is found that the internal friction angle and the burial depth of weak layer affect the slope stability. It is also found that the expansion pressure due to gas hydrate disassociation in weak layer can affect the stability also.
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