Multiscale Meshfree Analysis of Failure in Geostructures Founded on or Containing Liquefiable Soils

地震作用下边坡的失稳破坏分析是岩土地震工程中的一个重要问题。 虽然已经开发并在实践中使用了各种基于几何的和/或简化的方法，但当前对可液化土壤的应力-应变-强度行为的认识，近年来地震期间土壤边坡和隆起的大量观测响应，以及近年来工程结构数值模拟的重大进展，已经为更严格，但更现实，的方法来分析由摩擦引起的失稳和破坏。 该项目是开发一种多尺度的方法，它允许土壤响应被捕获在两个前和后失败的阶段与一个统一的本构模型。 此外，由于传统的有限元（FE）方法完全耦合的有效应力分析的土壤是严重限制在处理近和后故障响应的岩土系统，提出了一种无网格方法，以克服已知的困难的FE方法，并产生可靠和强大的解决方案，在液化分析的各个阶段。该项目的智力价值在于开发和引入两种非常强大的本构和数值方法来分析土壤液化。 所提出的方法将在公共领域的开源代码中实现，可供研究人员和从业人员使用。 开发的计算工具将通过对土壤斜坡和路堤响应的一系列实验和现场观察进行验证和验证。该项目更广泛的影响包括本研究中开发的技术在其他工程领域的潜在应用，例如生物孔隙力学和金属和合金的热轧工艺。 在这个项目的过程中培训的研究生将有一个很好的机会，发展液化和液化引起的变形和破坏的机制，以及在岩土系统建模的专业知识，使用两个最先进的分析和建模方法在工程力学的透彻理解。 这种研究训练的深度和广度应该对岩土工程实践具有重要价值。

Analysis of liquefaction-induced instability and failure in slopes and embankments is an important problem of geotechnical earthquake engineering. While various empirically-based and/or simplified approaches have been developed and used in practice, the current state of knowledge of stress-strain-strength behavior of liquefiable soils, the wealth of observed response of soil slopes and embankments during recent earthquakes, and the significant progress in numerical modeling of engineering structures in recent years, have prepared the ground for a more rigorous, yet realistic, approach to the analysis of liquefaction-induced instability and failure. This project is to develop a multiscale approach, which allows the soil response to be captured in both pre- and post-failure stages with a unified constitutive model. Moreover, since the traditional finite element (FE) approach for fully-coupled effective stress analysis of soils is severely limited in handling the near- and post-failure response of a geotechnical system, a meshfree method is proposed to overcome the known difficulties of an FE approach, and to produce reliable and robust solutions in all stages of a liquefaction analysis. The intellectual merit of the project lies in the development and introduction of two very powerful constitutive and numerical methods in the analysis of soil liquefaction. The proposed methods will be implemented in a public domain open source code, which can be used by researchers and practitioners. The developed computational tool will be validated and verified against a series of experimental and field observations on the responses of soil slopes and embankments.The broader impacts of the project include the potential use of the techniques developed in this research in other fields of engineering such as bio-poromechanics and hot rolling processes in metals and alloys. The graduate students trained in the course of this project will have an excellent opportunity to develop a thorough understanding of the mechanisms involved in liquefaction and liquefaction-induced deformation and failure as well as an expertise in modeling of geotechnical systems using two of the most advanced methods of analysis and modeling in engineering mechanics. The depth and breadth of such research training should be of significant value to geotechnical engineering practice.