EAPSI: Achieving seismic resilience by understanding liquefaction effects in Christchurch, New Zealand

EAPSI：通过了解新西兰基督城的液化效应来实现抗震能力

• 批准号: 1414671
• 负责人: Christine Beyzaei
• 金额: $ 0.51万
• 依托单位: Beyzaei Christine Z
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-01 至 2015-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1414671&HistoricalAwards=false
• 关键词: EAPSI; Achieving; seismic; resilience; understanding

Earthquakes are natural hazards that occur throughout the world, causing ground shaking and the potential for significant damage. During ground shaking, water pressure in the surrounding soil increases. When the water pressure exceeds a certain threshold, the soil collapses, becoming fluid and flowing up through the ground surface. This phenomenon, called liquefaction, causes ground settlements that affect both above- and below-ground structures. During the 2010-2011 Canterbury Earthquake Sequence, several large earthquakes took place over a 16 month period near Christchurch in New Zealand. Liquefaction damage from these earthquakes affected a significant large area around Christchurch, damaging buildings, infrastructure networks, and critical lifeline systems. This degree of extensive repeated liquefaction was virtually unprecedented in a modern urban setting. Through field sampling in Christchurch and a geotechnical laboratory testing program, this research will contribute to the current understanding of liquefaction. This research will be conducted at the University of Canterbury, in collaboration with Dr. Misko Cubrinovski.During the post-earthquake engineering investigation in Christchurch, an important observation was made: state-of-practice methods incorrectly predicted the occurrence and severity of liquefaction for many sites with fine-grained (silty) soils. State-of-practice methods for assessing liquefaction potential are largely based on clean sands; there remains considerable debate as to whether fine-grained soils will liquefy and the appropriate assessment procedure to employ. This research aims to advance the state of knowledge on liquefaction of fine-grained soils, while evaluating the level of conservatism in current state-of-practice liquefaction assessment methods. Hydraulic fixed-piston soil samples will be obtained from sites throughout Christchurch and cyclic stress ratio (CSR) curves will be developed through cyclic triaxial testing. Laboratory results will be compared with post-earthquake field observations and established liquefaction assessment procedures to evaluate the nature of liquefaction in fine-grained soils. The implications of these results will advance seismic resilience for cities faced with similar liquefaction hazards. This NSF EAPSI award is funded in collaboration with the Royal Society of New Zealand.

地震是发生在世界各地的自然灾害，造成地面震动和重大损害的可能性。在地面震动时，周围土壤中的水压力增加。当水压超过一定的阈值时，土壤就会塌陷，变成液体并通过地面向上流动。这种现象称为液化，会导致地面沉降，影响地上和地下结构。在2010-2011年坎特伯雷地震序列期间，新西兰基督城附近在16个月内发生了几次大地震。这些地震造成的液化破坏影响了基督城周围的大片地区，破坏了建筑物、基础设施网络和关键的生命线系统。这种大规模的反复液化在现代城市环境中几乎是前所未有的。通过在基督城的现场取样和岩土实验室测试程序，这项研究将有助于目前对液化的理解。这项研究将在坎特伯雷大学与Misko Cubrinovski博士合作进行。在基督城的地震后工程调查期间，进行了一项重要的观察：实践方法错误地预测了许多细粒（粉质）土壤场地的液化发生和严重程度。评估液化潜力的实践方法主要基于干净的砂;关于细粒土是否会液化以及采用适当的评估程序，仍存在相当大的争议。本研究的目的是提高对细粒土液化的认识，同时评估当前实践液化评估方法的保守性水平。将从整个基督城的现场获取液压固定活塞土壤样品，并通过循环三轴试验绘制循环应力比（CSR）曲线。实验室结果将与地震后的现场观察和既定的液化评估程序进行比较，以评估细粒土壤的液化性质。这些结果的影响将提高面临类似液化危害的城市的抗震能力。这个NSF EAPSI奖是与新西兰皇家学会合作资助的。