考虑超孔压影响的海底能源土斜坡稳定性数值模拟和评价

水合物分解极易引起海底能源土出现超孔压现象,进而导致能源土变形,引发海底滑坡等地质灾害。本文基于热力学基本理论,并考虑水合物最终分解状态下的相态演变,以及水合物分解过程中海水对甲烷气体的溶解,修正了孔隙气体非逃逸的Grozic超孔压模型,并将修正模型应用到海底能源土斜坡稳定性分析中。研究结果表明：考虑甲烷气体在海水中的溶解,采用修正模型计算的超孔压值相比于原模型减小约26%；水合物分解过程中,相比土体强度参数软化这一不利因素,超孔压积聚对斜坡稳定性影响更为明显,因此在海底能源土斜坡稳定性分析中,必须考虑超孔压积聚这一不利因素。

Numerical Simulation and Evaluation of the Stability of Submarine Energy Soil Slope Considering the Effect of the Excess Pore Pressure

Dissociation of gas hydrate can easily cause the excess pore pressure in submarine energy soils, leading to deformation and triggering geological disasters such as landslides. Using the basic idea of thermodynamics, and the phase evolution of the hydrates in the final dissociation state, the Grozic excess pore pressure is modified by considering the dissolution of methane gas from seawater during hydrate dissociation. The modified model is applied to analyze the slope stability of submarine energy soils. The results of the study show that the calculated value of the excess pore pressure using the modified model can be up to 26% different from the original model, and it is more accurate because the dissolved methane gas in seawater is taken into account; In the process of hydrate dissociation, compared with the unfavorable factors of softening of soil strength parameters, the accumulation of excess pore pressure has a more negative impact on slope stability. Therefore, it is necessary to consider the adverse factor of excess pore pressure in the analysis of slope stability of submarine energy soils.