RAPID: Liquefaction and Its Effects on Buildings and Lifelines in the February 22, 2011 Christchurch, New Zealand Earthquake

这项快速反应研究补助金(RAPID)奖提供资金，用于调查2011年2月22日新西兰克赖斯特彻奇6.1兆瓦地震和2010年9月4日新西兰达菲尔德7.0兆瓦地震期间液化对建筑环境的影响，目的是捕获易腐烂的数据，从而开发改进的分析方法，对危险进行全面评估。克赖斯特彻奇地震引起的强烈地面震动和土壤液化破坏了许多建筑、生命线和工程系统。克赖斯特彻奇的中央商务区(CBD)仍是一片废墟。2月22日的地震特别有意义，因为它发生在达菲尔德地震5个月后，震中距离CBD约40公里。2月22日的事件造成近200人死亡，而9月的事件没有造成死亡。此外，尽管9月4日的事件在克赖斯特彻奇地区造成了广泛的液化破坏，但它并没有在CBD内造成重大的液化破坏。通过比较这两次地震中土壤液化的不同程度，以及评估建筑物、生命线和工程系统在这两次地震中的不同抗震性能，可以学到很多东西。有机会了解相同的地面和基础设施如何应对两次重大地震，这是极其罕见的。这两次地震的震级和距离是美国城市经常考虑的两种情况。捕捉横向扩散的细节和液化对建造良好的结构的影响，如办公楼及其相互连接的地下公用设施，至关重要。了解当地地质条件如何影响观测到的破坏模式也很重要。现场勘察的重点是捕捉易腐烂的数据并通过以下步骤来表征地下条件：(1)开挖液化特征，(2)进行动态触探试验，(3)测量剪切波速。新西兰的建筑规范与美国使用的类似，最近的建设，可以学到许多直接适用于美国各地地震区的知识。这项研究正在通过地球工程极端事件侦察(GER)协会并与美国大学合作进行协调。坎特伯雷和新西兰政府。对设计级地震后的观测进行记录和学习，对于推动地震工程的实践是非常有价值的。调查液化的再次发生，记录液化引起的地面移动的案例，并评估液化对建筑物和生命线的影响，这些都提供了宝贵的信息，这些信息将作为该专业了解地震影响的基准。这些地震还涉及多重危险效应。这两次地震期间液化造成的联合沉降使克赖斯特彻奇的许多社区面临着更大的河流和海洋洪水的威胁，包括海啸。液化引起的地面移动数据的收集将成为洪水风险评估和地震脆弱性评估的基础。这项研究结合了几位主要研究人员的努力，从整体上检查液化的影响。该团队还包括一名初级教员和处于职业生涯早期的研究生，因此这将有助于发展他们在地震工程方面的能力，并使他们能够在新西兰建立研究联系。

This Grant for Rapid Response Research (RAPID) award provides funding to investigate the effects of liquefaction on the built environment during the 22 February 2011, Mw=6.1 Christchurch, New Zealand, earthquake and the 4 September 2010, Mw=7.0 Darfield, New Zealand, earthquake with the goal of capturing perishable data that would lead to the development of enhanced analytical procedures for evaluating the hazard holistically. The intense ground shaking and resulting soil liquefaction from the Christchurch earthquake damaged many buildings, lifelines, and engineered systems. The Central Business District (CBD) of Christchurch is still in ruins. The 22 February event is particularly meaningful, because it occurred just 5 months after the Darfield earthquake, the epicenter of which was approximately 40 km from the CBD. Whereas the 22 February event killed almost two hundred people, the September event resulted in no deaths. Additionally, although the 4 September event caused widespread liquefaction-induced damage in the Christchurch area, it did not produce significant liquefaction-induced damage within the CBD. There is much to learn from comparing the different levels of soil liquefaction from these two earthquakes and from evaluating the differing seismic performance of buildings, lifelines, and engineered systems during these two earthquakes. It is extremely rare to have the opportunity to learn how the same ground and infrastructure responded to two significant earthquakes. The magnitude and distances of these two earthquakes are two of the scenarios often considered in US cities. Capturing details of lateral spreads and the impacts of liquefaction on well-built structures, such as office buildings and their interconnecting buried utilities, are critically important. Understanding how local geologic conditions influenced the observed damage patterns is also important. Field reconnaissance is focusing on capturing perishable data and characterizing the subsurface conditions through: (1) trenching of liquefaction features, (2) performing dynamic cone penetration tests, and (3) measuring shear wave velocities (Vs).The effects of soil liquefaction on the built environment in the Christhurch area were pervasive. The New Zealand building code is similar to that used in the U.S., and with much recent construction, there is much that can be learned that is directly applicable to seismic regions across the U.S. This study is being coordinated through the Geoengineering Extreme Events Reconnaissance (GEER) Association and in collaboration with the Univ. of Canterbury and the New Zealand government. Documenting and learning from observations after design level earthquakes are invaluable to advancing the state-of-practice in earthquake engineering. Surveying the re-occurrence of liquefaction, documenting cases of liquefaction-induced ground movements, and evaluating the effects of liquefaction on buildings and lifelines provide invaluable information that will serve as benchmarks to the profession's understanding of the effects of earthquakes. These earthquakes involve also multi-hazard effects. The combined settlement caused by liquefaction during both earthquakes has exposed many Christchurch neighborhoods to increased threats from river and ocean flooding, including tsunami. Collection of data on liquefaction-induced ground movement will form the basis for flood risk assessment as well as earthquake vulnerability. The study combines the efforts of several leading researchers to examine the effects of liquefaction holistically. The team also includes a junior faculty member and graduate students who are in the early stages of their careers, so it will help develop their capabilities in earthquake engineering and allow them to establish research contacts in New Zealand.