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RAPID: Evaluation of Pre and Post Blast Liquefaction Soil and Site Parameters

RAPID：爆破液化前后土壤和场地参数的评估

基本信息

批准号：
2002382
负责人：
Jonathan Hubler
金额：
$ 4.94万
依托单位：
Villanova University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2019
资助国家：
美国
起止时间：
2019-12-01 至 2022-11-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2002382&HistoricalAwards=false
关键词：
RAPID Evaluation Pre Post Blast

项目摘要

Soil liquefaction is a phenomenon that can occur in saturated, loose sand and silt sediments during earthquake shaking which causes these soils to behave as a viscous fluid. This results in loss of strength and stiffness, often causing significant damage to civil infrastructure, such as buildings, bridges, and dams. Advances in soil liquefaction engineering have aided engineers in prediction of the initiation of liquefaction (triggering) and its consequences, thereby reducing casualties and damage to infrastructure. However, changes in soil properties both during and following liquefaction, and the affect that these changes can have on soil stiffness and settlement require further study to improve prediction of both post-liquefaction response and behavior during future earthquake events. This Grant for Rapid Response Research (RAPID) project will leverage existing field-testing equipment available from the Natural Hazards Engineering Research Infrastructure (NHERI) RAPID facility and blast testing already occurring as part of another NSF award to measure changes in soil parameters as a result of liquefaction. Measurements will be taken before, during, and after blast-induced liquefaction tests that are scheduled in New Zealand. The blast-liquefaction testing will occur at two locations: one with natural soils and one with soils that have been improved by resin injection. The site offers the opportunity to evaluate both native soils that liquefied during the 2010-2011 Canterbury Earthquake Sequence, as well as improved soils that represent a promising ground improvement technique to mitigate differential settlements and surface manifestations of liquefaction. The results have immediate application to regions of the United States which are prone to liquefaction. This project will enhance international collaboration among scientists and will involve students in an international research experience.The objective of this RAPID project is to further understand liquefaction effects on soil (e.g., shear wave velocity [VS], settlement) and site (e.g., fundamental frequency, amplification, vulnerability index) parameters by utilizing equipment from the RAPID facility to measure properties during blast-induced liquefaction testing occurring in New Zealand. Equipment that will be utilized from the NHERI RAPID facility includes: Seismometers, an instrumented dynamic cone penetrometer (DCP), multi-channel analysis of surface waves (MASW), and a 3D terrestrial laser scanner. The outcomes of this research will result in measurements of: (1) fundamental frequency and amplification factors before, immediately following liquefaction as the pore pressures dissipate, and after liquefaction when pore pressures have fully dissipated, (2) VS and DCP resistance before, immediately following, and after liquefaction, and (3) spatial ground deformations (i.e., settlement and lateral movement) at the liquefaction site using lidar scanners. A unique dataset of soil and site parameters will be created for pre and post liquefaction scenarios at two varying sites, enabling evaluation of changes in soil and site parameters as a result of liquefaction and improving our understanding of the effect of these changes on design of earthquake resilient infrastructure.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

土壤液化是一种在地震震动过程中可能发生在饱和松散砂和粉砂沉积物中的现象，这导致这些土壤表现为粘性流体。这导致强度和刚度的损失，通常会对民用基础设施（如建筑物、桥梁和水坝）造成重大损坏。土壤液化工程的进展有助于工程师预测液化的开始（触发）及其后果，从而减少人员伤亡和对基础设施的破坏。然而，在液化过程中和液化后土壤性质的变化，以及这些变化对土壤刚度和沉降的影响，需要进一步研究，以提高预测液化后的反应和行为在未来的地震事件。该快速反应研究（RAPID）项目将利用自然灾害工程研究基础设施（NHERI）RAPID设施提供的现有现场测试设备，以及作为另一项NSF奖励的一部分已经进行的爆炸测试，以测量液化导致的土壤参数变化。将在新西兰进行爆炸液化试验之前、期间和之后进行测量。爆炸液化试验将在两个地点进行：一个是天然土壤，另一个是通过树脂注入改良的土壤。该场地提供了评估2010-2011年坎特伯雷地震序列期间液化的原生土壤以及代表有前途的地基改良技术的改良土壤的机会，以减轻不均匀沉降和液化的表面表现。研究结果可直接应用于美国容易液化的地区。该项目将加强科学家之间的国际合作，并将使学生参与国际研究经验。该RAPID项目的目标是进一步了解液化对土壤的影响（例如，剪切波速度[VS]，沉降）和场地（例如，基频、放大率、易损性指数）参数，利用RAPID设施的设备测量新西兰爆炸液化试验期间的特性。NHERI RAPID设施将使用的设备包括：地震仪、仪表化动态锥形地震仪（DCP）、多通道表面波分析（MASW）和三维地面激光扫描仪。这项研究的结果将导致测量：（1）基本频率和放大系数之前，紧接着液化孔隙压力消散，液化后孔隙压力完全消散，（2）VS和DCP阻力之前，紧接着，液化后，和（3）空间地面变形（即，沉降和横向移动）。将在两个不同地点为液化前和液化后的情况创建一个独特的土壤和场地参数数据集，该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识产权进行评估来支持。优点和更广泛的影响审查标准。