含天然气水合物土的关键试验技术与工程力学特性研究

Methane gas-hydrate, commonly occurring in marine continental margin and beneath permafrost sediments worldwide, is a huge potential energy resource of great interest for the energy production industry. Thus far, however, comprehensive knowledge of the engineering properties of hydrate-bearing sediments is lacking, which greatly impedes the production and utilization of gas hydrates. Oriented to the engineering properties, mechanical behavior and coupling multi-processes of the hydrate-bearing sediments under the disturbance of gas recovery, this research is proposed to investigate the associated experimental techniques and procedures that are crucial in studying the mechanical behavior of the hydrate-bearing soils (denoted as HBS for short). Based on experimental study, theoretical modeling and numerical analysis, we explore the mechanisms of the origin and development of deformation and failure of HBS systems during the recovery processes, and develop a comprehensive theoretical framework for modeling the mechanical response of HBS. Finally, an effective numerical procedure is developed for evaluating and analyzing the recovery-related engineering and geological hazards. This research will provide vital theoretical and technical support for mitigating production-related hazards such as borehole, local and regional slope stability and optimizing the recovery procedures for extracting methane from HBS.

天然气水合物广泛分布于海底大陆架边缘的地层以及寒区永久冻土层中，是一种储量巨大且极具开发价值的战略性替代能源。然而，由于目前对含水合物土的工程特性缺乏充分的认识，人类在天然气水合物开发利用方面面临着重大挑战。本项目围绕开采扰动下含天然气水合物土的工程力学特性、变形与破坏机理、多过程耦合效应等问题，重点开展关键的测试技术、试验方法、理论模拟以及数值分析研究，突破制约含天然气水合物土的工程力学特性测试的关键技术瓶颈，建成高水平的有关含天然气水合物土工程力学特性的测试平台，在深刻揭示开采扰动下土层变形与破坏机理的基础上，建立能够描述开采扰动下含天然气水合物土的动态演化过程所必需的理论和数值模型，提出开采扰动对含天然气水合物地层力学稳定性影响的科学的评价与分析方法，为防治水合物开采诱发的工程与地质灾害问题、优化开采方案等提供理论依据和技术支持。

天然气水合物是一种储量巨大且极具开发价值的战略性替代能源, 由于目前对含水合物土的工程特性缺乏充分的认识，人类在天然气水合物开发利用方面面临着重大挑战。本项目围绕开采扰动下含天然气水合物土的工程力学特性、变形与破坏机理、多过程耦合效应等问题，重点开展仪器研制、试验方法、理论模拟以及数值分析等研究。利用新建的试验平台，结合提出的含水合物土试样制备法进行了含水合物土力学试验，同时进行了模拟水合物开采扰动下土层破坏的模型试验。基于试验结果建立了水合物相平衡模型与力学本构模型。利用数值分析模拟了开采扰动下含天然气水合物土的动态演化过程。提出开采扰动对含天然气水合物地层力学稳定性影响的科学的评价与分析方法，为防治水合物开采诱发的工程与地质灾害问题、优化开采方案等提供理论依据和技术支持。