CAREER: Characterization and Modeling of Marine Clays for Slope Stability

海底边坡的稳定性问题越来越受到人们的关注。全球经济需要更好、范围更广的基础设施，能够迅速将石油和天然气等资源从生产点分配到使用点。不断扩大的横跨海底的电信电缆网络和斜坡破坏造成的破坏将中断或延迟世界各地的信息流动。大型海底滑坡会引发海啸，对海浪路径上的沿海社区造成毁灭性的破坏。这项研究有助于理解软质海洋沉积物中海底斜坡在动载作用下的破坏机理。主要目标之一是开发一个广泛的简单剪切土壤行为数据库，专门针对墨西哥湾和西非海岸的近海粘土。实验结果是利用一种新的先进测试设备获得的，该设备是专门为在广泛的频率范围内进行多向加载而构建的。该试验用于表征土壤在不同初始和排水条件下的响应，以及不同加载路径下的响应，更接近于地震或风暴波的影响。此外，还研究了应变率对软粘土特性的影响。试验结果对本构模型的改进和验证是必不可少的，能够再现海相粘土的响应，并在用于海底斜坡响应分析的有限元程序中实现。通过参数研究，研究了导致故障触发的不同因素的重要性。通过对选定案例的研究，预测工具得到了验证。这项工作的更广泛影响包括提高学生和公众对地震如何影响土壤以及土壤如何改变地面震动的认识。本科生使用研究生开发的模型，参与构建针对不同能力水平的用户的可视化工具。这些活动还包括编写教材，将研究纳入数学和科学教学，并通过教师研究体验方案并与南得克萨斯州农村系统倡议合作，对教师进行培训。这项研究被引入到本科生和研究生的课程中。国际和平协会与沃思沃斯科学与历史博物馆合作，正在开发一个关于自然灾害的展览。

Increasing attention is being focused on the problem of submarine slope stability. The global economy requires a better, wider reaching infrastructure, able to quickly distribute resources, such as oil and gas, from the point of production to the points of use. An expanding network of telecommunication cables cross the ocean floors and breakages caused by slope failures would interrupt or delay the flow of information around the world. Large submarine slides can cause tsunamis, which can be devastating for the coastal communities in the wave's path.This research contributes to the understanding of failure mechanisms for submarine slopes in soft marine sediments subjected to dynamic loading. One of the primary goals is to develop an extensive database of soil behavior in simple shear, specifically targeting offshore clays from the Gulf of Mexico and off the coast of West Africa. The experimental results are obtained using a new advanced testing device, which has been specifically constructed for multidirectional loading at a wide range of frequencies. The testing is used to characterize the response of the soils subjected to different initial and drainage conditions, and a variety of loading paths, replicating more closely the effects of earthquakes or storm waves. The importance of strain rate on the behavior of soft clays is also investigated. The test results are essential for the refinement and validation of a constitutive model, able to replicate the response of the marine clays, and implemented in a finite element program for the analysis of submarine slope response. The importance of the different factors contributing to the triggering of failures is investigated through parametric studies. The predictive tools are validated through the study of selected case histories. The broader impacts of this work include increasing awareness among students and the general public of how earthquakes affect soils, and how ground shaking is also changed by the soils. Undergraduate students are involved in building visualization tools targeting users at different levels of ability, using the model developed by the graduate students. The activities also involve development of educational materials integrating research into the teaching of math and science, and the training of teachers, through a Research Experience for Teachers Program and in collaboration with the South Texas Rural Systemic Initiative. The research is introduced in courses at the undergraduate and graduate level. The PI, in partnership with the Forth Worth Museum of Science and History, is developing an exhibit on natural hazards.