RUI: Understanding the Role of Flexible and Rigid Barriers in Mitigating Surface Blast Effects on Underground Structures

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。在拟议的项目中，将调查与地下结构（如隧道和管道）相邻的柔性和刚性保护屏障受到表面爆炸的影响。 离心机是这类实验的一个有吸引力的工具，因为爆炸规模的影响是离心机比例因子的立方，因此在离心机模型中使用少量炸药可以产生与原型规模上大量炸药相同的效果。 离心模型试验的结果将用于校准三维数值模型，该模型将用于模拟表面爆炸，使用显式动力分析技术。 在技术文献中有充分的记载，使用土工离心机进行试验，模拟爆炸对模型的影响。 最近还采用数值分析来模拟爆炸的影响。 该项目包括物理和数值模拟的协同使用，以了解不同屏障在减轻爆炸影响方面的作用。 该项目将继续PI？的早期工作，其中报告了紧邻地下结构的柔性屏障的潜在缓解作用。 将进一步研究早期研究中确定的有益效果的局限性。 一旦校准，数值模型将用于了解各种参数的影响，例如屏障的刚度和厚度，土壤的相对密度，爆炸的大小和位置等。本项目将提供土壤参数和保护屏障对地面爆炸对地下结构造成的损害的影响的了解。 土，障碍物和地下结构之间的相互作用，由于动态加载，如爆炸是不太清楚。 利用离心和数值模拟的研究预计将提供有价值的理解。本项目将作为本科研究机构（RUI）进行。 一名本科生研究助理将与PI一起从事该项目，并将获得宝贵的研究经验，特别是与伦斯勒理工学院（RPI）的合作。 该项目的活动将与曼哈顿学院（主要是本科院校）的本科生和研究生以及参加该学院暑期工程课程的当地高中学生分享。 估计共有120名学生将受到该项目的影响。 来自RPI的实验的现场视频广播将向曼哈顿学院的学生（高中生、本科生和研究生）播放。 在拟议的研究（实验涉及爆炸和动画从数值模型）和重点专题问题（恐怖威胁）强烈的视觉元素预计将吸引学生，并向他们展示土木工程专业可以为国土安全作出贡献的方式。

This award is funded under the American Recovery and Reinvestment Act of 2009(Public Law 111-5).The effects of flexible and rigid protective barriers adjacent to underground structures (such as tunnels and pipelines) subjected to surface explosions will be investigated in the proposed project. The centrifuge is an attractive tool for this type of experiments, since the effects of a blast scale as the cubed of the centrifuge scaling factor, such that a small quantity of explosives can be used in a centrifuge model to create the same effects as a much larger quantity of explosives on a prototype scale. The results from centrifuge model tests will be used to calibrate a three-dimensional numerical model, which will be used to simulate the surface blast, using explicit dynamic analyses technique. The use of a geotechnical centrifuge to conduct tests where the effects of blasts are simulated on models is well-documented in technical literature. Numerical analyses have also been recently employed to simulate effects of explosions. This project includes synergistic use of physical and numerical modeling to understand the role of different barriers in mitigating the effects of explosions. The project will continue the PI?s earlier work in which the potential mitigating effects of flexible barriers immediately adjacent to underground structures were reported. Limitations to the beneficial effects identified in earlier research will be further investigated. Once calibrated, the numerical model will be utilized to understand the influence of various parameters, such as stiffness and thickness of barrier, relative density of soil, size and location of explosion, etc.This project will provide an understanding of the influence of soil parameters and protective barriers on damage caused by surface blasts on underground structures. The interaction between soil, barrier, and underground structure due to dynamic loading such as explosions is not well-understood. A study utilizing both centrifuge and numerical modeling is expected to provide valuable understanding.This project will be undertaken as Research in Undergraduate Institution (RUI). An undergraduate research assistant will work on this project with the PI and will gain valuable research experience, especially from collaborative work with Rensselaer Polytechnic Institute (RPI). The activities of this project will be shared with undergraduate and graduate students at Manhattan College (a predominantly undergraduate institution) as well as students from local high schools, who participate in summer engineering programs at the College. An estimated total of 120 students will be impacted by the project. Live video broadcasts of the experiments from RPI will be shown to students (high school, undergraduate and graduate) at Manhattan College. The strong visual elements in the proposed study (experiments involving blasts and animation from numerical model) and the emphasis on topical issue (terrorist threat) are expected to appeal to students and demonstrate to them ways in which the Civil Engineering profession can contribute to Homeland Security.