题  目：PModeling Unsaturated Granular Subgrade Material Behavior and Its Effects on Pavement Deformation

非饱和颗粒路基材料性状模拟及其对路面变形的影响

时  间：2019年7月5日9：30-11:00

地  点：7号楼学术报告厅

报告人：Balasingam Muhunthan  Professor and Chair Department of Civil and Environmental Engineering, Washington State University）

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                                      土木与交通学院

                                      2019年6月27日

报告人简介：

Muhunthan博士，P.E.，F.ASCE，华盛顿州立大学土木与环境工程系教授和主任，华盛顿X射线计算机断层扫描中心的创始人兼主任，以及华盛顿州立大学华盛顿州交通研究项目主任，曾在剑桥大学、奥克兰大学和佐治亚理工学院担任访问教授。

Muhunthan博士在University of Peradeniya获得土木工程学士学位，在Purdue University获得土木工程硕士和博士学位，Muhunthan博士的研究专长为计算和实验岩土力学。他曾参与广泛的岩土工程领域，包括山体滑坡、大坝失效、微型桩、斜坡水平排水沟和岩石坠落防护措施。 Muhunthan博士在他的研究领域有着广泛的出版记录。

Muhunthan博士因其学术成就获得了多个奖项。他是WSU所有三个顶级CEE部门奖项的获得者：杰出的教学，卓越的研究，以及Leon Luck最有效的教授奖。他还获得了华盛顿州立大学工程与建筑学院颁发的杰出教师奖，英国土木工程师学会颁发的克兰普顿奖，国家科学基金会颁发的国际奖学金奖，剑桥丘吉尔学院奖学金，普渡大学优异奖学金。Muhunthan博士是ASCE岩土特性和模拟委员会的成员，the International Journal of Geomechanics编委，主持过许多国内和国际会议，并在岩土材料本构模型方面进行了多次邀请讲座。

报告摘要：

Subgrade granular materials undergo repeated loading and their response influences the fatigue and rutting of asphalt concrete pavements. Granular materials exhibit a wide range of mechanical behavior that depends on their composition and fabric, stress history, density, and the nature of the applied force. In addition, most subgrade materials are unsaturated and their behavior is dependent on suction and water content. Subgrades with different moisture contents experience different suction force that affects their performance.  However, this effect has traditionally been difficult to be quantified using either empirical or mechanistic methods.

A new constitutive model for sands that accounts for their unsaturated behavior is presented.  It is based on critical state and bounding surface concepts and incorporates parameters that account for sand fabric and suction. The model is implemented into ABAQUS finite element software using UMAT subroutine. A 3-D FE model was developed to simulate response of pavements subgrades under differing vehicular loading magnitudes, asphalt and base properties, and saturation levels. It is shown that moduli of asphalt and base and saturation level of subgrades, were found to influence the vertical deformation experienced near the top of subgrade, especially at high wheel loads, but their influence gradually reduced with depth.