Advanced computational geomechanics for analysis of earth structures

岩土[地震]工程建模的未来将是基于性能的设计（PBD），本质上是基于位移的土结构。PBD和屈服后行为的评估需要向基于位移或变形的设计范式转变，而不是传统的基于力的设计，这种设计已经应用于土力学和基础工程问题。非线性材料在不规则地震荷载作用下的真实三维模拟是非常复杂的。为此，我们需要先进而高效的计算工具。这些工具需要处理一些岩土工程中的关键建模点，如瞬态加载，超孔隙压力的真实产生和消散的完全耦合固流相互作用，三维分析，结构元素的包含以及土基质的本构行为，这是成功的数值模拟的关键部分。当前建议的长期目标是将建模带到下一个层次，并为研究和工程社区提供更新和更准确的分析方法。这里的重点将给予砂和粘土在地震荷载下的高级本构模型和三维框架的数值模拟。提出的研究成果将为岩土材料循环荷载数值模拟提供两种新的本构模型。从结果的校准和解释的角度来看，这些本构模型将是高效和严谨的，但简单和用户友好。新开发的模型将有效地集成到FLAC3D计算框架中，这将扩展其在高级研究社区和设计实践中的适用性。将使用UBC、NGI、NEES和C-Core的实验数据进行广泛的验证和验证。最后，在开发的工具的应用方面，在许多相关问题中，重点将放在土-桩相互作用问题分析，地震事件下结构粘土海底稳定性研究以及大坝三维表征中的潜在问题。

The future of modeling in Geotechnical [Earthquake] Engineering will be all about Performance-Based Design, PBD, essentially displacement based for earth structures. PBD and the evaluation of post-yield behavior require a paradigm shift toward a displacement or deformation-based design, as opposed to the traditional force-based design that has been applied to soil mechanics and foundation engineering problems. A realistic 3D simulation of the nonlinear material subjected to irregular earthquake loading is very complex. For this purpose, one needs advanced and efficient computational tools. Such tools need to handle a number of key modeling points in geotechnical engineering such as transient loading, fully coupled solid-fluid interaction for realistic generation and dissipation of excess pore pressure, three-dimensional analyses, inclusion of structural elements, and constitutive behavior of the soil matrix, which is the crucial part of a successful numerical simulation. The long-term aim of the present proposal is to bring the modeling to the next level, and to provide newer and more accurate means of analysis to the research and engineering communities. The focus here will be given to advanced constitutive modeling of sands and clays in seismic loading, and numerical simulation in 3D framework. The proposed research outcome would generate two novel constitutive models for numerical simulation of cyclic loading in geomaterials. These constitutive models will be efficient and rigorous, yet simple and user friendly from the perspective of calibration and interpretation of results. The newly developed models will be efficiently integrated into the FLAC3D computational framework, which will extend their applicability in the advanced research community and design practice. An extensive verification and validation will be conducted using the experimental data available at UBC, NGI, NEES and C-Core. Finally, on application of the developed tools, among many relevant problems, focus will be given to analysis of soil-pile interaction problems, study on ocean floor stability in structured clays under seismic events, and underlying issues in 3D characterization of dams.