Study of Blast-Induced Liquefaction: A U.S.-Japan Collaborative Effort on Airport Infrastructure

该项目利用了在日本进行大规模爆炸诱导液化实验的合作机会。2007年10月，港口和机场研究所（PARI）在国土、基础设施和交通部提供的相当于180万美元的资金下进行了这项实验。实验将使用控制爆破技术液化8000平方米的区域，以调查机场基础设施的性能。PARI邀请Ashford教授参与规划、数据收集和分析，从而提出一种具有成本效益的方法，以提高我们对控制爆破、地面改善和机场基础设施性能的理解。PI与PARI有着长期成功的合作历史，最引人注目的是PI和PARI于2001年在日本Tokachi港联合进行的控制爆破的全规模横向扩展实验。该项目位于日本仙台附近，最近在那里放置了12米的松散粉砂作为港口扩建的水力填充物。PARI将在36000平方米的测试区域内建造4个25米× 80米的测试区域，以调查沥青跑道、混凝土跑道停机坪和开放区域下改善地面的性能，其中一个测试可用于其他研究。管道和混凝土公用管道也将放置在每个区域。地面改善技术包括砂-水泥混合、垂直排水和胶体硅注入。这项由美国国家科学基金会资助的工作的主要目标是增加我们对爆炸诱发液化的认识，近年来，爆炸诱发液化已用于地震诱发液化的现场尺度模拟，特别是在深基础响应领域。这种物理建模的方法有些争议，而这一显著增加知识库的机会将有助于评估早期研究的有效性。这项拟议研究的次要目标是提高我们对液化后改善的地面和机场基础设施性能的理解。为了实现这些目标，PI和美国地质勘探局的Robert Kayen博士将与PARI合作进行实验。使用SASW和LIDAR技术，我们将获得爆破前后的刚度和变形变化数据，以换取项目收集的所有数据的充分共享。虽然PARI收集的大部分数据最终将被公开，但我们参与项目规划和数据采集将确保在美国及时传播。完成我们的项目目标将提高我们对爆炸诱发液化的理解。这将有助于评估该实验技术是否适用于地震液化的物理建模，并确定潜在的局限性。对于更广泛的社区来说，这些数据和随后的分析也将阐明控制爆破作为评估液化潜力的直接方法的潜力，而不是目前采用的间接方法。该项目还将加强美国和日本研究人员之间的联系，并鼓励未来的此类合作。此外，研究结果将建立从业者的信心，研究人员愿意批判性地检查我们的实验方法。更重要的是，这个项目的视频和演示将被用来激发本科生对高等学位的兴趣。具体来说，PI计划与加州大学路易斯·斯托克斯少数民族参与联盟合作，确定一名本科生实习生参与该项目。

This project takes advantage of a window of opportunity for collaboration on a large-scale blast-induced liquefaction experiment in Japan. In October 2007, the Port and Airport Research Institute (PARI) is conducting the experiment with funding from the Ministry of Land, Infrastructure and Transportation which is the equivalent of $1.8 million US dollars. The experiment will use controlled blasting techniques to liquefy an 8000 m2 area to investigate the performance of airport infrastructure. PARI has invited the Professor Ashford to participate in the planning, data collection, and analysis, thus presenting a cost-effective means to improve our understanding of controlled blasting, ground improvement, and the performance of airport infrastructure. The PI has a long history of successful collaborations with PARI, most notably the full-scale lateral spreading experiment using controlled blasting conducted jointly by the PI and PARI at the Port of Tokachi, Japan, in 2001.The project is located near Sendai, Japan, where 12m of loose silty sand was recently placed as hydraulic fill for a port expansion. PARI will build four 25m by 80m test sections within the 36,000m2 test area to investigate the performance of improved ground under asphalt runways, concrete runway aprons, and open areas, with one test available for other studies. Pipelines and concrete utility conduits will also be placed in each area. Ground improvement techniques to be used include sand-cement mixing, vertical drains, and colloidal silica injection. The primary objective of this NSF-funded effort is to increase our knowledge of blast-induced liquefaction which has been used in recent years for field-scale modeling of earthquake induced liquefaction, particularly in the area of deep foundation response. This method of physical modeling is somewhat controversial, and this opportunity to significantly add to the knowledge-base will help assess the validity of earlier studies. The secondary objectives of this proposed research are to improve our understanding of the performance of improved ground and airport infrastructure subjected to liquefaction. To accomplish these objectives, the PI and Dr. Robert Kayen of the USGS will collaborate with PARI on the experiment. Using SASW and LIDAR technology, we will obtain data on stiffness and deformation changes before and after the blasting in return for full sharing of all data collected on the project. While most of the data collected by PARI would eventually be made public, our participation in the project planning and data acquisition will ensure timely dissemination in the US.Fulfilling our project objectives will improve our understanding of blast-induced liquefaction. This will help assess whether this experimental technique is appropriate for physical modeling of earthquake induced liquefaction, and identify potential limitations. For the broader community, the data and subsequent analysis will also shed light on the potential of controlled blasting to be used as a direct method of assessing the liquefaction potential, rather than the indirect methods currently employed. This project will also strengthen ties between US and Japanese researchers and encourage such collaborations in the future. In addition, the results will build confidence in practitioners that researchers are willing to critically examine our experimental methods. More importantly, the video and presentations from this project will be used to excite undergraduates about advanced degrees. Specifically, the PI plans to work with UC's Louis Stokes Alliance for Minority Participation to identify an undergraduate intern to participate in the project.