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

地震对建筑环境的灾难性影响，包括建筑物、桥梁、水坝和发电厂，通常是由土壤液化引起的地面故障引起的。液化是指饱和砂土在地震作用下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结构上实施。迫切需要开发一种具有成本效益和实用的防止液化技术，这种技术既可以应用于新场地，也可以应用于现有结构基于可液化土壤的场地。这项研究将探索推进一个创新的概念，即诱导部分饱和（IPS），其中可液化砂的水饱和度降低，从而防止其在地震中破坏。诱导部分饱和是指在可液化的砂土中注入一种生成气体的化学溶液，通过溶液的运输和反应性，在砂土的孔隙中产生可控的氧气气泡，从而降低地层中的含水饱和度。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阻止了液化的发生。这项研究的结果将推动IPS技术成为一种技术上可行、实用且具有成本效益的液化缓解技术。IPS将产生广泛的影响，包括降低全球地震风险。此外，所获得的基本知识将大大有助于加强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主要问题。此外，这项研究将继续为初高中学生和教师创造独特的机会，参与研究人员的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。研究结果将在研究人员的网站上公布。本研究的数据和发现将被上传到nsf支持的NHERI数据仓库。本研究的目的是研究和推进诱导部分饱和作为一种可行的液化缓解现场技术。为了实现这一目标，将开展以下三个主要研究任务：1)评估易液化的IPS处理现场砂的行为；2)开发数值模拟以模拟真实现场条件下的IPS过程；3)在东北大学戴德姆校区的试验台进行现场实验性能评估，以提高对IPS处理砂的基础知识，并验证所开发的数值模拟。研究任务将为在实际现场条件下诱导部分饱和以及现场砂体对IPS处理的行为提供新的基础知识。该研究还将创造机会，开发实施IPS的现场工具和方法，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.