Multidimensional constitutive and numerical modeling in geotechnical seismic analysis and design

岩土地震分析和设计中的多维本构和数值建模

• 批准号: RGPIN-2015-03777
• 负责人: Taiebat, Mahdi
• 金额: $ 2.48万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=685309
• 关键词: Multidimensional; constitutive; numerical; modeling; geotechnical

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. ***The proposed research will address several challenging aspects of constitutive and numerical modeling of sand, silt, and clay under complex multidirectional loading. A series of related laboratory element test data will be collected and studied in detail. The information will be used in development of several novel constitutive modeling features for multidirectional cyclic loading of sands, silts and clay. The highlight would be on development of the SANISAND-Z model with zero elastic range, refined inherent and evolving fabric for multidirectional loading, and provisions for accumulation of large post-liquefaction shear deformation. Also the important feature of rate-dependency will be added to the recently developed SANICLAY-B model. The developed models will be robustly implemented in FLAC3D, OPENSEES and/or DIANA. The models and developed tools will be extensively verified and validated using element test and centrifuge test results. On the application side among many relevant problems focus will be given to the very challenging and important problems of (i) multidimensional seismic site response analysis, and (ii) seismic deformation analysis of earth dams, which gives the loss of freeboard in extreme events, and also study of the efficiency of remedial measures for the dam stability. The developed modeling tools and simulations lead to revisiting conventional seismic analysis and design with PBSD, which is of significant relevance to the reduction of seismic risk in Canada.**

岩土技术工程中建模的未来几乎完全基于基于绩效的地震设计理念。与传统的基于力的设计相反，PBSD需要向基于变形或基于变形的设计范式转变。它比传统的分析和设计方法更合理，并导致更具成本效益的结构或更安全的设计。 PBSD需要足够的计算变形可靠性度量。对经过不规则地震负荷的地理结构变形的现实模拟非常复杂。模拟工具应基于有效的应力公式，完全耦合的固体流体相互作用以及处理大问题的平行/云计算功能来处理3D动态分析。最重要的问题是土壤基质的适当组成型建模。工程实践中使用的当前土壤模型不包括影响应力应变关系的许多非常重要的因素。解决地震的多向循环载荷也是极具挑战性的。从与主要从业人员（例如与地球大坝打交道的卑诗省水力）进行的讨论中，很明显，他们的主要关注点是可用的不同模型给出的不同反应。在某些情况下，这些差异足以引起人们的关注。 ***拟议的研究将解决在复杂的多向载荷下的构成型和数值建模的几个具有挑战性的方面。将详细收集和研究一系列相关的实验室元素测试数据。该信息将用于开发几种新型的组成型建模特征，以用于沙子，淤泥和粘土的多向循环载荷。亮点将是开发具有零弹性范围的Sanisand-Z模型，用于多向载荷的固有和不断发展的织物，以及积累大型后地面剪切变形的规定。同样，依赖性依赖性的重要特征将添加到最近开发的Saniclay-B模型中。开发的模型将在FLAC3D，OpenSees和/或Diana中实现。模型和开发的工具将通过元素测试和离心机测试结果进行广泛验证和验证。在许多相关问题的应用方面，将重点放在（i）多维地震现场反应分析的非常具有挑战性和重要问题上，以及（ii）地球大坝的地震变形分析，这在极端事件中损失了自由板的损失，并研究了补救措施对大坝稳定性的补救措施效率。开发的建模工具和仿真可通过PBSD重新审视常规的地震分析和设计，这与加拿大的地震风险降低至关重要。**