Field Application of Induced Partial Saturation (IPS) for Liquefaction Mitigation

地震对我们的建筑环境（包括建筑物、桥梁、水坝和发电厂）的灾难性影响通常是由土壤液化引起的地面破坏造成的。 液化是指在地震中饱和桑迪失去支撑结构的承载能力。 可用于防止液化发生的现有技术非常昂贵，并且只能在新的地点和现有的结构中实施。 迫切需要开发一种具有成本效益和实用性的液化预防技术，该技术可应用于新场地以及现有结构位于可液化土壤上的场地。 这项研究将探索推进一个创新的概念，称为诱导部分饱和（IPS），其中可液化砂的水饱和度降低，从而防止其在地震期间的故障。 诱导部分饱和涉及将产生气体的化学溶液注入可液化的桑迪地面中，通过溶液的运输和反应性导致在砂的孔隙内受控地产生氧气气泡，从而降低地面中的水饱和度。 东北大学的这个研究小组进行的研究表明，沙子的部分饱和确实可以防止液化的发生。 这项研究的结果将推进IPS作为一种技术上可行的，实用的，具有成本效益的液化缓解现场技术。 IPS将产生广泛的影响，包括减少全球地震风险。 此外，所获得的基本知识将大大有助于加强受污染地下水的补救和恢复技术，这是一个对人类健康有重大影响的重大问题。 此外，这项研究将继续为初中和高中学生和教师创造独特的机会，参加研究人员地震工程实验室的活动，通过演示和动手结构模型创建和测试来促进科学和工程。 研究结果将通过研究人员的网站公布和提供。 本研究的数据和发现将上传到NSF支持的NHERI数据仓库。本研究的目标是调查和推进诱导部分饱和作为液化缓解的可行现场技术。 为实现这一目标，将开展以下三项主要研究任务：1）评价经IPS处理的易液化场地砂的特性，2）开发数值模拟以模拟真实的场地条件下的IPS过程，和3）在东北大学Dedham校区的试验台上进行的现场实验的性能评估，以提高IPS处理砂的基础知识，验证所开发的数值模拟。 研究任务将导致在真实的现场条件下诱导部分饱和的新的基础知识，以及对IPS处理的现场砂的行为。 该研究还将创造机会，开发现场工具和方法，实施IPS以及数值模拟软件，以确定IPS作为地震液化缓解措施的现场应用的设计概念和参数。

Catastrophic effects of earthquakes on our built environment including, buildings, bridges, dams, and power plants, are often caused by ground failures due to soil liquefaction. Liquefaction refers to the loss of bearing capacity of saturated sandy soils to support structures during earthquakes. Existing techniques that can be used to prevent occurrence of liquefaction are very costly and can only be implemented at new sites and only at existing structures. There is a critical need to develop a cost-effective and practical liquefaction prevention technology that can be applied to new sites as well as sites with existing structures resting on liquefiable soils. This research will explore advancing an innovative concept referred to Induced Partial Saturation (IPS) in which water saturation of a liquefiable sands is reduced, thus preventing its failure during earthquakes. Induced Partial Saturation involves injection of a gas generating chemical solution into the liquefiable sandy ground, leading to controlled generation of oxygen gas bubbles within the pores of the sand through transport and reactivity of the solution, thus reducing water saturation in the ground. Research conducted by this team at Northeastern University demonstrated that partial saturation of sands indeed prevents the occurrence of liquefaction. The outcome of this research will advance IPS as a technically feasible, practical, and cost-effective field technique for liquefaction mitigation. IPS will have broad impacts, including reducing earthquake risk worldwide. Also, the fundamental knowledge gained will have significant benefits in enhancing technologies for remediation and restoration of contaminated groundwater, a major problem with significant impacts on human health. Furthermore, this research will continue to create unique opportunities for middle and high school students and teachers to participate in activities in the researchers' earthquake engineering laboratory, promoting science and engineering through demonstrations and hands-on structural model creation and testing. The research outcomes will be published and made available through the researchers' website. The data and finding of this research will be uploaded to the NSF-supported NHERI Data Depot.The goal of this research is to investigate and advance Induced Partial Saturation as a feasible field technique for liquefaction mitigation. To achieve this goal, the following three primary research tasks will be conducted: 1) Evaluation of behavior of liquefaction susceptible field sands treated by IPS, 2) Development of numerical simulation to model the IPS process under real field conditions, and 3) Evaluation of the performance of field experiments at a testbed at the Dedham campus of Northeastern University to advance fundamental knowledge on IPS treated sands and to verify the developed numerical simulation. The research tasks will lead to new fundamental knowledge on inducing partial saturation under real field conditions, and on the behavior of field sands to IPS treatment. The research will also create opportunities to develop field tools and methods for implementation of IPS as well as numerical simulation software to determine design concepts and parameters for field application of IPS as an earthquake liquefaction mitigation measure.