Evaluation of Earthquake-Induced Liquefaction Damage Potential to Infrastructure

最近在新西兰、智利和日本发生的地震突出了地震引起的液化对自然和建筑环境的破坏性影响。 例如，2010-2011年新西兰坎特伯雷地震序列导致基督城的地下公用设施、道路、建筑物和其他基础设施损失约350亿美元，其中大部分损失是液化的直接后果。 “将灾难转化为知识”，该奖项支持开发一个框架，利用最近地震的丰富现场性能数据，以及来自有据可查的历史液化案例历史和补充计算机模拟的数据，评估基础设施的液化破坏潜力。本研究项目的动机是需要适当考虑触发和损害的框架内，尊重他们的根本差异，系统地分类液化的严重程度，并将其与整个土壤剖面的响应，消除了很多的主观性解释液化的情况下，历史用于开发触发曲线，并避免了双重计算的因素，影响液化损害的潜力。 该奖项的结果将有助于通过改进目前的液化风险评估方法来最大限度地减少地震造成的损失。 此外，教育的影响不仅会导致增加的技术理解的主题，但也将导致与同事在新西兰，智利和日本的国际合作。液化触发和由此产生的损害之间的区别是模糊的主观性，在目前的方法用于开发液化“触发”曲线。 其原因是液化“触发”曲线主要基于观测到的地表表现数据的严重程度。 因此，所谓的简化液化“触发”曲线实际上是“触发”曲线和“地表显现”曲线的组合。 因此，在目前的液化破坏潜力指数框架内使用这些曲线本身就双重计算了影响液化破坏潜力的因素。 这对于可靠地评估由于液化引起的风险尤其是一个问题。 该奖项支持在一个一致的框架内开发液化触发曲线和损害潜力指数，该框架提供了液化触发和液化损害潜力的明确分离和适当核算。 最值得注意的是，该框架避免了将液化发生与剖面内的特定层联系起来的需要;相反，该框架整合了每个案例历史的整个剖面的信息。 对液化表现的严重程度进行分级，形成统一、客观的液化危险性评价方法。将使用贝叶斯更新技术分析现场性能数据，以开发基于概率的“真实”液化触发曲线。 该技术还将用于确定与液化严重度的不同概率相对应的潜在损害指数值，其中液化严重度用作潜在损害的代理。 然而，这个框架将保留简化的液化触发评估程序和液化潜力指数制定的优雅和简单，因为他们熟悉的执业工程师。

The recent earthquakes in New Zealand, Chile, and Japan highlight the damaging effects of earthquake-induced liquefaction on both the natural and built environments. For example the 2010-2011 Canterbury, New Zealand, earthquake sequence resulted in approximately $35 billion in damage to buried utilities, roads, buildings, and other infrastructure in Christchurch, with much of the damage being a direct consequence of liquefaction. "Turning disaster into knowledge," this award supports the development of a framework to assess liquefaction damage potential on infrastructure using the wealth of field performance data from the recent earthquakes, as well as data from well-documented historic liquefaction case histories and supplemental computer simulations. This research project is motivated by the need to properly account for triggering and damage within a framework that respects their fundamental differences, systematically classifies the severity of liquefaction and relates it to the response of the entire soil profile, removes much of the subjectivity in interpreting liquefaction case histories used to develop triggering curves, and avoids the double counting of factors that influence liquefaction damage potential. The results of this award will help minimize losses from earthquakes by improving the current methods for liquefaction risk assessment. Furthermore, the educational impacts will not only result from the increased technical understanding of the subject matter, but will also result from the international collaborations with colleagues in New Zealand, Chile, and Japan.The distinction between liquefaction triggering and the resulting damage is blurred by subjectivity in current approaches used to develop liquefaction "triggering" curves. The reason for this is that liquefaction "triggering" curves are primarily based on observed severity of surface manifestation data. As a result, the purported simplified liquefaction "triggering" curves are actually combined "triggering" and "surface manifestation" curves. Consequently, the use of these curves within current liquefaction damage potential index frameworks inherently double counts factors that influence liquefaction damage potential. This is particularly an issue for reliably assessing the risk due to liquefaction. This award supports the development of a liquefaction triggering curve and damage potential index within a consistent framework that provides a clear separation and proper accounting of liquefaction triggering and liquefaction damage potential. Most notably, this framework avoids the need to tie liquefaction occurrence to a specific layer within a profile; instead, this framework integrates information from the entire profile for each case history. The classification of manifestation severity will follow a detailed rubric such that a unified and objective approach for liquefaction hazard assessment is formed. The field performance data will be analyzed using the Bayesian updating technique to develop a probabilistically based "true" liquefaction triggering curve. This technique will also be used to determine the damage potential index values that correspond to different probabilities of liquefaction severity, where liquefaction severity is used as a proxy for damage potential. However, this framework will preserve the elegance and simplicity of the simplified liquefaction triggering evaluation procedure and Liquefaction Potential Index formulation because of their familiarity to practicing engineers.