基于颗粒组构模型的水合物沉积物三轴压缩力学性质研究

Triaxial Compression Mechanical Behavior of the Hydrate Sediments Based on Particles Arranged Model

摘要: 天然气水合物是一种重要的新型清洁能源，具有广阔的开发前景。天然气水合物沉积物可看作土颗粒与水合物颗粒组成的混合物，具有明显的非连续力学特征。针对水合物沉积物力学性质，本文采用同时生成土体–水合物两种类型颗粒并赋予线性接触的方式制备不同饱和度的水合物沉积物颗粒组构模型试样，并研究其三轴压缩力学特性。本文模拟水合物的力学性质结果与Brugada等结果取得较好的一致。研究结果表明：水合物沉积物的峰值强度及残余强度随着水合物饱和度增加而增大；围压的增加有助于提高试样弹性模量、剪切强度、体积应变等力学参数；饱和度的变化对水合物沉积物试样内摩擦角影响显著。本研究可为水合物的安全开采提供基础力学参数和技术参考。

Abstract: Natural methane hydrate is an important clean energy with broad exploration prospects. Methane hydrate sediment may be regarded as a mixture of soil and hydrate particles, which has typical discontinuous mechanical behaviors. Focusing on the mechanical properties of hydrate sediment, a series of triaxial compression simulations were performed based on the particles arranged model samples. The hydrate sediment samples with different hydrate saturation were prepared through generating soil particles and hydrate particle simultaneously and giving them liner contacts. The simulation results are in good agreement with Brugada’s study. The simulations show that the peak strength and residual strength of hydrate sediment increased with hydrate saturation. The confining pressure has an important effect on the elastic modulus, shear strength, volumetric response of hydrate sediment. The hydrate saturations contribute to the internal frictional of hydrate sediment. This study provides a mechanical parameter database and technical reference for the safe exploitation of methane hydrate.