Multidimensional constitutive and numerical modeling in geotechnical seismic analysis and design

岩土地震工程建模的未来将几乎完全基于基于性能的地震设计理念。PBSD要求从传统的基于力的设计转向基于位移或变形的设计。它比传统的分析和设计方法更合理，并导致更经济有效的施工或更安全的设计。PBSD要求对计算变形有足够的可靠性。不规则地震荷载作用下土工结构变形的真实模拟是非常复杂的。仿真工具应处理基于有效应力公式、完全耦合固-孔-流体相互作用以及并行/云计算特征的三维动态分析，以处理大型问题。最重要的问题是正确的土基质本构模型。目前工程实践中使用的土体模型没有包括许多影响应力-应变关系的重要因素。处理地震的多向循环载荷也是极具挑战性的。从与主要实践者的讨论中，例如处理土坝的卑诗水电公司，很明显，他们主要关心的是不同可用模型给出的不同响应；在某些情况下，这些差异足以引起极大的关注。

The future of modeling in geotechnical earthquake engineering will be based almost exclusively on Performance-Based Seismic Design philosophy. PBSD requires a paradigm shift toward a displacement or deformation-based design as opposed to the traditional force-based design. It is more rational than the conventional analysis and design methods, and leads to more cost effective construction or safer design. PBSD demands an adequate measure of reliability of computed deformations. A realistic simulation of deformation of geo-structures subjected to irregular earthquake loading is very complex. The simulation tools should handle 3D dynamic analysis based on effective stress formulation, fully coupled solid-pore fluid interaction, and parallel/cloud computing features for handling large problems. The most important issue is proper constitutive modeling of the soil matrix. Current soil models used in engineering practice do not include many of the very important factors that affect the stress-strain relationship. It is also extremely challenging to address multidirectional cyclic loading of earthquakes. From discussion made with major practitioners, such as BC Hydro who deal with earth dams, it becomes clear that their main concern is with the different responses given by the different models that are available; in some cases these differences are significant enough to cause great concern.