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.**

岩土地震工程建模的未来将几乎完全基于基于性能的抗震设计理念。 PBSD 需要向基于位移或变形的设计转变，而不是传统的基于力的设计。它比传统的分析和设计方法更加合理，可以实现更具成本效益的施工或更安全的设计。 PBSD 要求对计算变形的可靠性进行充分的测量。对不规则地震荷载作用下的地质结构变形的真实模拟非常复杂。模拟工具应基于有效应力公式、完全耦合的固体-孔隙流体相互作用以及用于处理大型问题的并行/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正确本构建模。当前工程实践中使用的土壤模型不包括许多影响应力应变关系的非常重要的因素。解决地震的多向循环载荷也极具挑战性。从与主要从业者（例如处理土坝的 BC Hydro）的讨论中可以看出，他们主要关心的是可用的不同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关注。 ***拟议的研究将解决复杂多向载荷下沙子、淤泥和粘土的本构和数值模拟的几个具有挑战性的方面。将收集一系列相关的实验室元素测试数据并进行详细研究。这些信息将用于开发几种新颖的本构模型特征，用于沙子、粉砂和粘土的多向循环荷载。重点是开发 SANISAND-Z 模型，该模型具有零弹性范围、用于多方向载荷的精致固有和不断发展的织物，以及用于积累大液化后剪切变形的规定。此外，速率依赖性的重要特征也将被添加到最近开发的 SANICLAY-B 模型中。开发的模型将在 FLAC3D、OPENSEES 和/或 DIANA 中得到可靠实施。模型和开发的工具将使用元件测试和离心机测试结果进行广泛的验证和验证。在许多相关问题的应用方面，重点将放在以下非常具有挑战性和重要的问题上：（i）多维地震场地响应分析，以及（ii）土坝地震变形分析，它给出了极端事件中的干舷损失，并研究大坝稳定性补救措施的有效性。开发的建模工具和模拟导致人们重新审视使​​用 PBSD 的传统地震分析和设计，这对于降低加拿大的地震风险具有重要意义。**