RAPID: Integrated Geotechnical and Geophysical Investigation of Subaqueous Foundations, Levees and River Banks Impacted by Hurricane Harvey

飓风哈维在2017年秋季造成严重的风灾和洪水。 事实上，相关的洪水可以被归类为5,000年一遇的事件。 与洪水有关，发生了重大的沉积物迁移过程。 水下结构物和基础周围的沉积物侵蚀，通常称为冲刷，对基础设施的稳定性构成重大风险。 在飓风哈维期间，早期的侦察队观察到桥墩、河流堤坝、板桩墙、巨石墙和其他基础设施有明显的冲刷和侵蚀。 然而，由于水位仍然很高，现场调查受到安全限制。 事件后冲刷和侵蚀调查的一个问题是冲刷坑的回填。 这意味着，当水位和流速下降时，悬浮物中的沉积物沉降并填充冲刷坑，往往导致对事件期间侵蚀程度的错误评估。 此外，填充物是新沉积的，通常很弱，可能会提供一个虚假的稳定形象。 该奖项将支持收集易腐现场数据，调查冲刷和侵蚀，以及在飓风哈维期间受洪水和风暴潮影响的地点进行事后填充。收集到的数据将促进对极端洪水事件期间冲刷、侵蚀和填充的理解，因此，直接有助于改进风险评估。研究小组将访问在哈维飓风期间经历严重冲刷和侵蚀的地点，以及早期侦察小组最初调查的地点。 将采用综合的岩土工程和地球物理方法收集冲刷和侵蚀以及随后的填充的独特数据集。 浅海底回声探测器（啁啾声纳）将在便携式自由落体重力仪部署的支持下，描绘水下沉积物地层，该重力仪将提供不同沉积层的岩土参数。 侧扫声纳和摄影测量将提供详细的图像和地形。 将使用内聚强度计测试现场可蚀性。 重力取芯法将能够在淹没地区进行沉积物取样，而推管取样法将在露出的堤岸进行。 将对沉积物样品进行土工沉积物特性和可侵蚀性测试。 后面的试验将使用侵蚀水槽装置进行。 收集的现场数据将是独一无二的，提供来自原生沉积物和填充物的岩土工程信息，并将使未来的研究和洞察与哈维飓风期间的极端洪水事件相关的侵蚀和填充过程。 这些数据将通过Designsafe-CI数据存储库收集后立即向公众和其他研究人员提供。

Hurricane Harvey caused severe wind damages and flooding in Fall, 2017. In fact, the associated flooding can be classified as a 5,000 year event. Associated to the flooding, significant sediment relocation processes occurred. Sediment erosion around submerged structures and foundations, commonly referred to as scour, represents a significant risk to the stability of infrastructures. During Hurricane Harvey, early reconnaissance teams observed significant scour and erosion at bridge piers, river embankments, sheet pile walls, boulder walls, and other infrastructure with submerged foundations. However, safety constraints limited on site investigations while water levels were still elevated. An issue of post-event scour and erosion investigations is the refilling of scour holes. This means that when with receding water levels and flow velocities, sediment transported in suspensions settles and infills the scour holes, often leading to false assessments of the magnitude of erosion during the event. Additionally, the infill is freshly deposited and often weak, potentially providing a false image of stability. This award will support the collection of perishable field data investigating scour and erosion, as well as post-event infill at locations impacted by flooding and storm surge during Hurricane Harvey. The collected data will advance the understanding of scour, erosion, and infill during extreme flooding events, and therefore, contribute directly to the improvement of risk assessment.The research team will visit sites that experienced severe scour and erosion during Hurricane Harvey, and that were initially investigated by early reconnaissance teams. An integrated geotechnical and geophysical approach will be employed to gather a unique data set of scour and erosion, and the subsequent infilling. Sub-bottom echo sounders (chirp sonar) will profile the submerged sediment stratigraphy, supported by portable free fall penetrometer deployments which will provide geotechnical parameters of the different sediment layers. Side scan sonar and photogrammetry will provide detailed imagery and topography. In-situ erodibility will be tested using a cohesive strength meter. Gravity coring will enable sediment sampling in submerged areas, while push tube sampling will be conducted at emerged banks. Sediment samples will be tested for geotechnical sediment characteristics, and erodibility. The latter tests will be conducted using a Erosion Flume Apparatus. The collected field data will be unique by providing geotechnical information from the native sediments and the infill, and will enable future research and insights into the erosion and infill processes associated to extreme flooding events as during Hurricane Harvey. The data will be made available to the public and other researchers immediately after collection through the Designsafe-CI data repository.