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。拟议的工程项目将研究受地面爆炸影响的地下结构（如隧道和管道）附近的柔性和刚性防护屏障的影响。对于这种类型的实验，离心机是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，这样，在离心机模型中使用少量炸药可以产生与在原型规模上使用大量炸药相同的效果。离心机模型试验的结果将用于校准三维数值模型，该模型将用于使用显式动态分析技术模拟表面爆炸。使用土工离心机进行试验，在模型上模拟爆炸的影响，这在技术文献中有充分的记录。数值分析最近也被用来模拟爆炸的影响。该项目包括协同使用物理和数值模拟，以了解不同屏障在减轻爆炸影响方面的作用。项目会继续PI吗？在早期的工作中，报告了紧挨着地下结构的柔性屏障的潜在缓解效果。在早期研究中确定的有益效果的局限性将进一步调查。校正后的数值模型将用于了解各种参数的影响，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。本项目将了解土壤参数和防护屏障对地面爆炸对地下结构的破坏的影响。由于爆炸等动力载荷，土壤、屏障和地下结构之间的相互作用尚不清楚。利用离心机和数值模拟的研究有望提供有价值的理解。本项目将作为本科生研究项目（RUI）进行。一名本科生研究助理将与PI一起研究这个项目，并将获得宝贵的研究经验，特别是与伦斯勒理工学院（RPI）的合作工作。这个项目的活动将与曼哈顿学院（主要是本科生机构）的本科生和研究生以及参加学院暑期工程课程的当地高中学生共享。估计总共有120名学生将受到这项计划的影响。RPI实验的现场视频广播将展示给曼哈顿学院的学生（高中、本科生和研究生）。拟议研究中强烈的视觉元素（涉及爆炸的实验和数值模型的动画）和对主题问题（恐怖主义威胁）的强调有望吸引学生，并向他们展示土木工程专业可以为国土安全做出贡献的方式。

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.