不同温压环境下深海能源土力学特性离散元分析

发布时间：2019-07-29 17:36

【摘要】：深海能源土宏观力学特性与所处温度与水压环境密切相关,明晰温压对能源土力学特性的影响对水合物的安全开采具有重要意义。首先,介绍深海能源土的温度水压力学微观胶结模型,用以描述能源土粒间的水合物胶结接触力学特性;其次,将该模型导入至离散元商业软件PFC2D中,开展不同温度与水压环境下的离散元双轴试验;最后,结合离散元双轴试验结果及同已有室内试验结果的对比分析,探讨温度与水压对深海能源土宏观力学特性的影响规律和微观作用机理。结果表明:引入胶结模型的离散元双轴试验可较好地描述深海能源土强度、变形等力学特性随温度与水压的变化关系;温度与水压影响深海能源土宏观力学特性的微观机理是颗粒间水合物胶结强度与刚度同温度与水压间的相关性;建议采用温压距离参数L(在无量纲化的温度水压坐标平面内,水合物赋存温度与水压点至其相平衡线的最小距离)评价实际复杂温压场下的深海能源土宏观力学特性。
[Abstract]:The macroscopic mechanical properties of deep-sea energy soil are closely related to the temperature and water pressure environment. It is of great significance to clarify the influence of temperature and pressure on the mechanical properties of energy and soil for the safe exploitation of hydrate. Firstly, the micro-bonding model of temperature / water pressure mechanics of deep-sea energy soil is introduced to describe the contact mechanical properties of hydrate bonding between energy soil particles. Secondly, the model is introduced into the discrete element commercial software PFC2D to carry out the discrete element biaxial test under different temperature and water pressure environment. Finally, combined with the results of discrete element biaxial test and the results of laboratory test, the influence of temperature and water pressure on the macroscopic mechanical properties of deep-sea energy soil and the mechanism of microcosmic action are discussed. The results show that the discrete element biaxial test with cement model can well describe the relationship between the strength and deformation of deep-sea energy soil and the relationship between temperature and water pressure, and the microscopic mechanism of the influence of temperature and water pressure on the macroscopic mechanical properties of deep-sea energy soil is the correlation between hydrate bonding strength and stiffness and temperature and water pressure. It is suggested that the temperature and pressure distance parameter L (the minimum distance between hydrate occurrence temperature and water pressure point to its phase equilibrium line in dimensionless temperature / water pressure coordinate plane) should be used to evaluate the macroscopic mechanical properties of deep sea energy soil under actual complex temperature and pressure field.
【作者单位】：同济大学土木学院地下建筑与工程系;岩土及地下工程教育部重点实验室;
【基金】：国家自然科学基金国家杰出青年基金项目(51025932) 国家自然科学重点基金项目(51239010) 教育部博士点基金项目(20100072110048)
【分类号】：P751;TU43

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