Energy Principles for Monotonic and Cyclic Loading of Cohensionless Soils

9304506 Muhunthan 在地震期间，地面运动将动能和势能输入土体或结构中。 这些系统在受到振动时耗散能量的能力是抗震系统设计的关键因素。 传统上，能量原理为抗震结构的设计提供了方法，但对于土壤动力学，该方法一直集中于基于应力应变的公式。 因此，该项目的动机是利用能量原理来检查土壤结构对地震荷载的响应，以量化直至破坏的土壤性能。 该研究项目的目的是确定和开发导致破坏和土壤液化的单调和循环载荷中相关能量特征之间的关系，并使用状态边界表面作为能量包络线，提供单调和循环载荷之间的统一联系。 作为这一发展的一部分，有必要研究国家边界表面的唯一性问题。 主要目标是： 1. 建立单调土壤行为的能量包络及其与状态边界表面的关系。 2. 研究当输入能量水平超过循环加载中的耗散能时液化开始的假设。 3. 根据能量原理，开发一个框架来分析液化引起的土壤破坏。 这是一个涉及华盛顿州立大学和佐治亚理工学院的合作研究项目。 ***

9304506 Muhunthan During an earthquake, the motion of the ground inputs both kinetic and potential energy into a soil mass or structure. The ability of these systems to dissipate this energy when subject to vibration is a key factor in the design of earthquake-resistant systems. Energy principle have traditionally provided methods for the design of earthquake- resistant structures, but for soil dynamics, the approach has been to concentrate on stress-strain based formulations. Thus, this project is motivated to examine the response of soil structures to earthquake loading using energy principles to quantify soil performance up to failure. The objective of this research project is to identify and develop the relationships between relevant energy characteristics in monotonic and cyclic loading leading up to failure and soil liquefaction, and to use the state boundary surface as an energy envelope that provides a unifying link between monotonic and cyclic loading. As part of this development, it is necessary to examine the question of uniqueness of the state boundary surface. The main objectives are: 1. Establish an energy envelope for monotonic soil behavior and its relationship to the state boundary surface. 2. Investigate the hypothesis that liquefaction initiates when the input energy level exceeds the dissipation energy in cyclic loading. 3. Develop a framework to analyze soil failure due to liquefaction, based on energy principles. This is a collaborative research project involving Washington State University and the Georgia Institute of Technology. ***