NSF East Asia and Pacific Summer Institute (EAPSI) for FY 2013 in New Zealand

这一行动资助弗吉尼亚理工大学的William Lake Carter于2013年夏天在新西兰基督城的坎特伯雷大学进行工程研究项目。该项目的标题是“利用表面波试验评估地基加固技术减轻地震液化风险的有效性”。“接待的科学家是布伦登布拉德利博士。在2010-2011年毁灭性的坎特伯雷地震序列之后，新西兰的基督城正处于重建状态。一个特别的重点是减轻未来的风险，从地震引起的液化在拟议的建筑工地的损害。地基加固技术，如石柱，通过增加土壤剖面的密度和横向有效限制来降低土壤液化的可能性。然而，石柱的安装技术是非标准化的，并且因公司而异;通过一种技术安装的石柱可能比使用另一种技术安装石柱的场地具有更低的液化潜力。本研究通过使用表面波测试评估改进的场地来确定地面改进技术及其安装技术的有效性。使用多道面波分析（MASW）设备，PI对基督城及其周边地区的各种改良地面进行有源横波剖面测量。在改良场地和邻近未改良场地进行试验，以提供比较。这两组测量转换成一维剪切波剖面，随后进行比较，以量化土壤改善定义的剪切波速度在整个网站的增加;剪切波速度的增加构成了土壤刚度和抗土壤液化的增加。 EAPSI奖学金的更广泛的影响包括为研究员提供美国以外的第一手研究经验;介绍各自所在地的科学，科学政策和科学基础设施;以及社会，文化和语言的方向。 这些活动符合NSF的目标，即在科学家，工程师和教育工作者的职业生涯早期进行国际合作教育，从而确保具有全球意识的美国科学工作者。 此外，拟议的研究将继续培养坎特伯雷大学和弗吉尼亚理工大学之间的专业和学术关系。我们也希望这两个研究小组将相互学习，并进一步提高世界各地地震风险缓解的专业知识。从这项研究中将是一个MS论文，这将记录这项独特的研究结果。预计这项研究的结果将通过在高质量的期刊和/或会议论文集上发表的方式与地震工程界分享。

This action funds William Lake Carter of Virginia Tech to conduct a research project in Engineering during the summer of 2013 at the University of Canterbury in Christchurch, New Zealand. The project title is "Use of Surface Wave Tests for Evaluating the Efficacy of Ground Improvement Techniques for Mitigating the Risk from Earthquake Induced Liquefaction." The host scientist is Dr. Brendon Bradley. After the devastating 2010-2011 Canterbury earthquake sequence, the city of Christchurch, New Zealand is in a state of rebuilding. A particular focus is on mitigating future risk of damage from earthquake induced liquefaction at proposed building sites. Ground improvement technologies, like stone columns, reduce soil liquefaction potential by increasing the density and lateral effective confinement of the soil profile. However, the installation technique for stone columns is non-standardized and varies from company to company; stone columns installed by one technique may have a lower liquefaction potential than sites where stone columns were installed using another technique. This research determines the effectiveness of ground improvement techniques and their installation techniques by evaluating the improved sites using surface wave tests. Using Multichannel Analysis of Surface Waves (MASW) equipment, the PI performs active source, shear wave profiling of various improved ground sites around Christchurch and its environs. The tests are performed at the improved ground sites and adjacent unimproved ground sites to provide a comparison. Both sets of measurements are transformed into one-dimensional shear wave profiles and subsequently, compared to quantify the soil improvement defined by an increase in shear wave velocity across the site; an increase in shear wave velocity constitutes an increase in soil stiffness and resistance against soil liquefaction. Broader impacts of an EAPSI fellowship include providing the Fellow a first-hand research experience outside the U.S.; an introduction to the science, science policy, and scientific infrastructure of the respective location; and an orientation to the society, culture and language. These activities meet the NSF goal to educate for international collaborations early in the career of its scientists, engineers, and educators, thus ensuring a globally aware U.S. scientific workforce. Furthermore, the proposed research will continue to cultivate the professional and academic relationship between the University of Canterbury and Virginia Tech. It is also hoped that both research groups will learn from each other and further the profession's knowledge of earthquake risk mitigation worldwide. Stemming from this research will be an MS thesis, which will document the findings of this unique study. It is expected that the findings from this research will be shared with the earthquake engineering community by publishing the results in a high quality journal and/or a conference proceedings.