SGER: Development of Field Delivery System of Oxygen Bubbles for Seismic and Geoenvironmental Hazard Mitigation

减轻冲突对建筑环境造成的损害仍然是土木工程领域的一个重要优先事项和重大挑战。 目前防止液化的土壤改良方法通常非常昂贵，并且其应用仅限于新的场地。 目前迫切需要开发具有成本效益的液化缓解措施，可应用于新的网站以及网站的结构存在。 PI和CO-PI一直在研究开发一种基于在完全饱和的可液化砂中诱导部分饱和度的液化缓解创新方法。 迄今为止的研究已经证明了该方法的技术可行性。 实验室试验得出的结论是，在砂中引入气泡，从而降低其饱和度，防止液化的发生。 虽然诱导部分饱和作为一种潜在的液化缓解措施的可行性已被成功地证明，它是PI和CO-PI？的最终目的是进一步推动这项缓解措施，通过实地研究测试证明其可行性，以便专业工程界考虑在实践中应用。 这将需要实施一项全面的研究计划，并在大规模实验室和现场条件下进行测试。 然而，这样的研究计划不能启动，也不能保证资金，除非两个不同的和重要的研究目标首先实现。本次SGER奖重点关注这两个研究目标。 拟议研究的第一个目标是设计一种输送系统，该系统可以在完全饱和的沙子中产生气泡，该系统可以在现场成功实施。 这种气体输送系统应该是实用的，并且能够快速且均匀地降低砂的饱和度。第二个重要的目标是设计一个现场测试技术，可用于评估气体输送系统的有效性，导致验证部分饱和度，以及现场补救的均匀性。从初步调查结果表明，氧气泡可以通过引入冷冻水与溶解？埃费尔登？（主要是过硼酸钠），或通过添加催化剂的冷却过氧化氢，以在流体温度升高时释放氧气。 此外，很明显，使用压电锥和超孔隙压力的测量过程中的压电锥渗透到沙子可以是一个实用的和快速的方式验证部分饱和度及其均匀性。 这些探索性研究活动将使用地下传感和成像系统中心（NSF-ERC-CenSSIS）的SoilBed设施进行。这项研究的结果可以帮助推进开发具有成本效益的液化缓解措施的努力，该措施可以对地震灾害的财产安全和保护产生全球影响。 开发具有成本效益的氧气输送系统也可以帮助原位生物修复方法在实践中更广泛地实施。 该研究是地震工程和地质环境工程领域的教师和学生之间的合作。 这种跨学科的合作带来了创新的想法，并继续使从事研究的本科生和研究生受益

Mitigation of liquefaction-induced damages to the built environment continues to be an important priority and a major challenge in civil engineering. Current soil improvement methods to safeguard against liquefaction are often very expensive and their applications are limited to new sites. There is an urgent need to develop cost-effective liquefaction mitigation measures that can be applied to new sites as well as sites where structures exist. The PI and CO-PI have been conducting research on developing an innovative method for liquefaction mitigation based on inducing partial degree of saturation in otherwise fully saturated liquefiable sands. The research to date has demonstrated the technical feasibility of the method. Laboratory tests have led to the conclusion that introduction of gas bubbles in sand, thus reducing its degree of saturation, prevents the occurrence of liquefaction. While the feasibility of induced partial saturation as a potential liquefaction mitigation measure has been successfully demonstrated, it is the PI and CO-PI?s ultimate goal to further advance this mitigation measure, prove its feasibility through field research tests so that the professional engineering community considers its application in practice. This will require implementation of a comprehensive research program with testing under large scale laboratory and field conditions. However, such a research program can not be embarked nor funding can be secured unless two distinct and important research goals are first achieved. This SGER award focuses on these two research goals. The first goal of the proposed research is to devise a delivery system that can generate gas bubbles in fully saturated sands that can be implemented with high likelihood of success in the field. This gas delivery system should be practical and be able to reduce the degree of saturation of sands rapidly and uniformly. The second important goal is to devise a field testing technique that can be used to assess the effectiveness of the gas delivery system leading to validation of partial degree of saturation, as well as the uniformity of the site remediation. Results from preliminary investigations suggest that oxygen bubbles can be generated within sands through the introduction of chilled water with dissolved ?Efferdent? (primarily sodium perborate), or through chilled hydrogen peroxide with an added catalyst to release oxygen when temperature of the fluid rises. Also, it is apparent that the use of a piezocone and measurement of excess pore pressures developed during the penetration of the piezocone into the sand can be a practical and rapid way of validating partial degree of saturation and its uniformity. These exploratory research activities will be conducted using the SoilBed facility of the Center for Subsurface Sensing and Imaging Systems (NSF-ERC-CenSSIS) The outcome of this research can help advance efforts at developing a cost-effective liquefaction mitigation measure that can have world-wide impact on safety and protection of property from earthquake hazards. Development of cost-effective oxygen delivery system can also help in situ bioremediation method to be more widely implemented in practice. The research is collaboration between faculty and students in the fields of earthquake engineering and geoenvironmental engineering. Such interdisciplinary collaborations have led to innovative ideas and continue benefiting undergraduate and graduate students engaged in the research