Collaborative Research: SWCC Based Models for Realistic Simulation of Swell Behavior of Expansive Soils

目前工程实践中对非饱和膨胀土体积变化特性的确定大多是基于简化试验，并与指标性质进行相关。这样的做法可能导致不经济和损坏倾向的基础设计。因此，有一个基本的研究需要审查目前的特性的做法，在膨胀土，并修改它们，以反映目前的知识状态的非饱和土力学。来自UT阿灵顿和亚利桑那州立大学的研究团队正在通过执行各种实验和建模任务来努力实现这一研究需求。实验任务包括调查八种类型的膨胀土，以确定土壤水分特征曲线（SWCCs）在很宽的土壤吸力，测量体积膨胀应变和膨胀压力考虑粘土矿物，含水量，干容重，应力历史。建模任务包括开发分析公式，使用SWCC属性、粘土矿物学、孔隙数据预测膨胀特性，并研究基于流动和变形的有限元建模，以模拟体积变化行为。本研究的最终成果是开发出利用非饱和土力学原理更好地预测膨胀土特性的方法，研究的更广泛影响将集中在培养研究生和本科生非饱和土力学和膨胀土特性方面，将研究成果纳入本科和研究生课程，加强对膨胀土体积变化特性的了解，为膨胀土基础设施基础设计提供更好的表征工具;让妇女和少数民族学生参与研究任务;以及在暑期班教授简单的实验单元，以提高学生对土木工程的兴趣。

Current engineering practice for determining the volume change behavior of unsaturated expansive soils are mostly based on simplified tests, and correlations with index properties. Such practices can lead to uneconomical and distress prone foundation designs. Hence, there is a fundamental research need to review the current characterization practices in expansive soils and to revise them to reflect the current state of knowledge of unsaturated soil mechanics. The research team from both UT Arlington and Arizona State University are working towards accomplishing this research need by performing various experimental and modeling tasks. Experimental tasks include investigations on eight types of expansive subsoils to determine Soil Water Characteristic Curves (SWCCs) over a wide range of soil suction, measure volumetric swell strain and swell pressure with consideration of clay mineralogy, moisture content, dry unit weight, and stress history. Modeling tasks include development of analytical formulations to predict swell characteristics using SWCC attributes, clay mineralogy, pore void data, and study flow and deformation based finite element modeling to simulate volume change behavior. The final outcome of this research is the development of methods for better predictions of expansive soil properties using unsaturated soil mechanics principles.The broader impacts of the research will focus on training graduate and undergraduate students in unsaturated soil mechanics and expansive soil characterization; incorporating research findings into undergraduate and graduate courses; strengthening understanding of volume change behavior of expansive soils and providing better characterization tools for design of infrastructure foundations on expansive soils; involving women and minority students in research tasks; and teaching simple experimental modules in summer classes to K-12 students to enhance their interests in civil engineering.