Influence of gassy soils and gas hydrates on submarine slope failure

近海地质灾害影响经济发展和海洋基础设施的安全运行。 发生在洋底的滑坡是一种常见的地质灾害，具有相当大的破坏和生命损失的可能性;然而，人们对海底滑坡的触发和演变还没有很好的了解。 在研究土壤中气体的影响时尤其如此。 气泡或水合物形式的天然气与许多海底边坡破坏有着密切的联系。 然而，它仍然是一个重大的挑战，将气体的作用，以定量分析和预测的海底斜坡故障。本研究旨在通过实验和理论相结合的方法，对海洋土壤中气体的重要性进行综合了解。 实验研究将使用位于卡尔加里大学两个新设施的定制土工测试设备，调查含有天然气和天然气水合物的土壤的基本行为。 本构模型，实验室程序的结果进行验证，将被开发来描述水合物分解和含气土壤卸载过程中的土壤的理论行为变化。 本构模型将被纳入稳定性评估，定量分析海底斜坡的稳定性。 最后，将综合所有阶段的结果，以制定有关海底斜坡稳定性的建议，特别强调控制参数，如气体含量、水合物含量、土壤条件、地形和海洋学数据。 这些建议最终将导致制定准则，以便能够评估现有基础设施和沿海发展受到损害的风险，并促进今后岸外发展的更安全和更具成本效益的设计。 由于寻找资源需要我们进入更深的水域、偏远地区和陌生的地区，而且不断增长的全球人口继续给已经迅速发展的沿海地区带来压力，因此，加强对海底条件的了解至关重要。

Offshore geohazards impact the economic development and safe operation of marine infrastructure.  Landslides occurring on the ocean floor are a common geohazard that have considerable potential for damage and loss of life; yet, the triggering and evolution of submarine slides is not well understood.  This is particularly true when examining the effects of gas in soils.  Gas, in bubble or hydrate form, has been circumstantially and theoretically linked to many submarine slope failures.  However, it remains a major challenge to integrate the role of gas into the quantitative analysis and prediction of submarine slope failures. This research is aimed at obtaining an integrated understanding of the significance of gas in marine soils using a combined experimental and theoretical approach.  Experimental studies will investigate the fundamental behaviour of soil containing gas and gas hydrates using customized geotechnical testing equipment located in two new facilities at the University of Calgary.  Constitutive models, verified with the results of the laboratory program, will be developed to describe the theoretical behavioural changes of the soil during hydrate dissociation and gassy soil unloading.  The constitutive models will then be incorporated into stability assessments to quantitatively analyze the stability of submarine slopes.  Finally, the results from all phases will be synthesized to develop recommendations regarding submarine slope stability, with particular emphasis on the governing parameters such as gas content, hydrate content, soil conditions, topography, and oceanographic data.  These recommendations will ultimately result in the development of guidelines that will enable the risk of damage to existing infrastructure and coastal developments to be evaluated and facilitate safer and more cost-effective designs of future offshore developments.  As the search for resources takes us into deeper water, remote regions, and unfamiliar territory, and the expanding global population continues increasing pressure to already burgeoning coastal areas, improved knowledge of the seabed conditions is of critical importance.