Research Initiation: Experimental Investigation and Constitutive Modeling of Cohesionless Soil Under Cyclic Loading

也许工程设计中最常见的问题， 土壤，是计算运动的问题， 将一般应力状态应用于土壤。 直到最后一 十到二十年，计算出 由小载荷引起的小运动（与载荷相比 导致倒塌），或计算倒塌荷载，并假设 运动是如此之大，以至于没有必要计算 他们 对于两个极端都不成立的常见情况， 有必要应用“工程判断”。“随着 现代数字计算机，研究人员正在从事一个双管齐下的 攻击这一类问题。 一种模式涉及试图 测量广义土壤性质（完整的应变状态， 对施加应力的一般状态的反应）和 模型来描述土壤的反应。 第二种模式涉及 发展数值方法，使所得的土壤性质， 可以用来预测现场的大规模运动。 这项建议 涉及第一种模式。 本研究的目标是对这些数据进行可靠的测量， 干净砂样品对复杂应力状态的响应，以及 然后拟合适当的模型，以分析描述 产生的属性。 所谓的空心圆柱装置将是 用来测量属性。 各种本构模型将 试过了 单调加载（载荷 直接破坏）和循环载荷（重复应用 应力小于破坏应力）。

Perhaps the most common problem in engineering design involving soils, is the problem of calculating the movements that result from application of general states of stress to the soils. Until the last ten to twenty years, it was feasible to calculate either the very small movements that resulted from small loads (compared to the load that causes collapse), or to calculate collapse loads and assume that movements were so large that it became unnecess- ary to calculate them. For common cases in which neither extreme was valid, it was necessary to apply "engineering judgement." With the advent of modern digital computers, researchers are engaged in a two-pronged attack on this class of problem. One mode involves attempts to measure generalized soil properties (complete state of strain in response to a generalized state of applied stress) and development of models to describe the soil response. The second mode involves development of numerical methods so the resulting soil properties can be used to predict mass movements in the field. This proposal involves the first mode. The goal of this research is to perform reliable measurements of the response of samples of clean sands to complex states of stress, and then to fit appropriate models to allow analytic description of the resulting properties. The socalled hollow-cylinder device will be used to measure properties. A variety of constitutive models will be tried. Both monotonic loading (load directly to failure) and cyclic loading (repeated application of stresses less than the failure stresses) will be used.