RAPID: Cone Penetration Testing (CPT) and Spectral Analysis of Surface Waves (SASW) Testing at Seismograph Stations with Liquefiable Soils Affected by the Tohoku Earthquake, Japan

RAPID：在受日本东北地震影响的可液化土壤地震台上进行锥入度测试 (CPT) 和面波频谱分析 (SASW) 测试

• 批准号: 1138168
• 负责人: Brady Cox
• 金额: $ 12.03万
• 依托单位: University of Arkansas
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-15 至 2012-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1138168&HistoricalAwards=false
• 关键词: RAPID; Cone; Penetration; Testing; CPT

This Grant for Rapid Response Research (RAPID) award is for a detailed study that focuses specifically on characterizing the soil conditions at a select set of strong ground motion recording stations that are underlain by liquefiable soils in regards to the March 11, 2011 magnitude 9.0 Tohoku, Japan Earthquake, which ranks as one of the largest in recorded history. In the aftermath of the earthquake, an advance team from the Geotechnical Extreme Events Reconnaissance (GEER) Association traveled to Japan to coordinate perishable data collection and research efforts with our Japanese colleagues from the Japanese Geotechnical Society, the Center for Urban Earthquake Engineering, and the Port and Airport Research Institute. On this visit, Cone Penetration Testing (CPT) and Spectral Analysis of Surface Waves (SASW) testing at key strong ground motion recording stations where liquefaction occurred were identified as priority research tasks that the US could contribute to joint US-Japan reconnaissance efforts. The GEER Advance Team visited 14 strong ground motion recording stations underlain by liquefiable soils in the Kanto Plain region, including several with both downhole and surface recordings. Peak ground accelerations at these stations ranged from 0.14 to 0.22 g, and surface evidence of liquefaction was observed at 7 of them. In addition, the Port and Airport Research Institute has indicated they have several strong ground motion recording stations further to the north, where shaking was stronger, that are underlain by liquefiable soils, including some with ground improvements. These key ground motion recordings represent a unique set of data that captures the dynamic response and liquefaction of soft soils during long-duration shaking produced by this M9.0 earthquake. As such, these data can be used to anchor liquefaction triggering curves and refine magnitude scaling factors, assess procedures for estimating ground surface deformations, and evaluate dynamic site response analysis models for liquefiable soils. However, proper characterization of these sites is an imperative step before subsequent analyses can be performed accurately. Subsurface information at these sites is currently limited to a single Standard Penetration Test (SPT) and downhole shear wave velocity (Vs) profile at each site. CPT soundings and many additional Vs profiles from SASW testing at six or more of the most significant strong ground motion recording stations will be obtained. CPT is often preferred over SPT in the US and much of the world for evaluating liquefaction triggering, but CPT is relatively uncommon in Japan for various reasons, and it is unlikely that this work will be performed by our Japanese colleagues. This work is an important and valuable contribution that will enhance the value of these case histories and tie them to US practice. The urgency of this project is due to: (1) the possibility of post-earthquake repair work that could modify ground conditions at key sites, and (2) the need for rapid distribution of CPT and SASW results, which will have maximum impact if obtained before the ground motion records are used for other research studies.The results of this study are expected to contribute to a significant advancement in the procedures used to predict and model liquefaction effects across the US and elsewhere in the world. Significant research collaborations have existed between the US and Japan since the 1964 Niigata Earthquake. Both counties have benefitted from this partnership, and have used these experiences as a spring board to lead the rest of the world in seismic design and building standards. The CPT and SASW testing will be performed in close coordination with our Japanese colleagues in an effort to continue this tradition by facilitating cross-training of researchers and students on testing practices in our respective countries, providing an avenue for new and important international collaborations.

该快速响应研究补助金 (RAPID) 奖项用于一项详细研究，该研究专门侧重于描述 2011 年 3 月 11 日东北地区震级 9.0 级地震的一组选定的强地震动记录站的土壤状况，这些记录站下方是可液化土壤。日本地震是有记录以来最大的地震之一。 地震发生后，岩土极端事件勘察 (GEER) 协会的先遣小组前往日本，与日本岩土工程学会、城市地震工程中心和日本地震研究所的日本同事协调易腐烂的数据收集和研究工作。港口机场研究所。 在这次访问中，在发生液化的主要强地震动记录站进行锥入度测试（CPT）和表面波频谱分析（SASW）测试被确定为美国可以为美日联合侦察工作做出贡献的优先研究任务。 GEER先行团队参观了关东平原地区可液化土壤下的14个强地震动记录站，其中包括几个同时进行井下和地面记录的站。 这些站点的峰值地面加速度范围为 0.14 至 0.22 g，其中 7 个站点观察到了液化的表面证据。 此外，港口和机场研究所表示，他们在北部有几个强烈的地面震动记录站，那里的震动更强，下面是可液化土壤，其中一些地面震动记录站经过了地面改良。 这些关键的地面运动记录代表了一组独特的数据，可捕获本次 M9.0 地震产生的长时间震动期间软土的动态响应和液化。 因此，这些数据可用于锚定液化触发曲线并细化幅度缩放因子、评估估计地表变形的程序以及评估可液化土壤的动态场地响应分析模型。 然而，在准确执行后续分析之前，必须对这些位点进行正确表征。 这些地点的地下信息目前仅限于每个地点的单个标准渗透测试 (SPT) 和井下剪切波速度 (Vs) 剖面。 将通过在六个或更多最重要的强地震动记录站进行的 SASW 测试获得 CPT 探测和许多附加 Vs 剖面。 在美国和世界大部分地区，CPT 通常比 SPT 更适合评估液化触发，但由于各种原因，CPT 在日本相对不常见，而且这项工作不太可能由我们的日本同事来完成。这项工作是一项重要且有价值的贡献，它将提高这些案例历史的价值并将其与美国实践联系起来。 该项目的紧迫性是因为：(1) 震后修复工作可能会改变关键地点的地面条件，(2) 需要快速分发 CPT 和 SASW 结果，如果发生这种情况，这将产生最大影响在地面运动记录用于其他研究之前获得。这项研究的结果预计将有助于在美国和世界其他地方预测和模拟液化效应的程序方面取得重大进步。 自 1964 年新泻地震以来，美国和日本之间一直存在着重要的研究合作。 两国都从这种伙伴关系中受益，并利用这些经验作为跳板，在抗震设计和建筑标准方面引领世界其他地区。 CPT 和 SASW 测试将与我们的日本同事密切协调进行，以通过促进研究人员和学生在我们各自国家的测试实践方面的交叉培训来延续这一传统，为新的重要的国际合作提供途径。