Distributed Acoustic Sensing (DAS) data from the NHERI@UTexas Thumper Shaker Truck and 240m of Fiber Along the Blackhawk Levee

On 21-22 October 2021, the NHERI@UTexas experimental facility, in collaboration with the University of California, Berkeley, the U.S. Army Corps of Engineers (USACE), and the Engineer Research and Development Center (ERDC) hosted a workshop on Fiber Optic Distributed Acoustic Sensing (DAS) for Infrastructure Engineering and Subsurface Imaging. Day 1 of the workshop was held at the LSU Center for River Studies from 9:00 am to 5:30 pm CST. Videos of presentations from Day 1 of the workshop are available at https://utexas.designsafe-ci.org/workshops/. Day 2 of the workshop included a field DAS imaging demonstration on a section of Mississippi River levee in Black Hawk, Louisiana, where approximately 2 km of fiber optic cable had been installed in both surface and borehole arrays as a means to image the levee at high spatial resolution and monitor seepage. This section of levee is of particular interest to the USACE because severe seepage was detected during a flood event in 2015. A sand boil on the landward side of the levee prompted an emergency retrofit. The USACE stopped the flow through the sand boil by placing a line of deep relief wells along the landward toe of the levee and covering the surface expression with a gravel pad. The purpose of the DAS imaging campaign is to assess the extent of internal erosion at the site and evaluate the use of DAS for such applications.
This project houses a publicly available DAS dataset from the workshop. More specifically, it contains DAS time histories at approximately 1-m channel separation from a 240-m long section of fiber optic cable buried in a shallow trench at the site. The DAS data was collected with an OptaSense ODH4+ interrogator using a 2-m gauge length. The seismic source for the data acquisition was the NHERI@UTexas Thumper vibroseis truck, which was used to generate vertical dynamic excitation in the form of 12-second long chirps over the frequency range of 5-200 Hz. DAS data acquired from 15 different shot points located parallel to the alignment of the cable are provided. Additional details about the experiment and data collected maybe found in the README file accompanying the dataset.

2021年10月21日至22日，NHERI@UTexas实验设施联合加州大学伯克利分校、美国陆军工程兵团（U.S. Army Corps of Engineers, USACE）与工程研究与发展中心（Engineer Research and Development Center, ERDC），举办了一场面向基础设施工程与地下成像的光纤分布式声学传感（Fiber Optic Distributed Acoustic Sensing, DAS）研讨会。研讨会首日于美国中部时间上午9:00至下午5:30在路易斯安那州立大学（Louisiana State University, LSU）河流研究中心举办，首日报告的视频可通过https://utexas.designsafe-ci.org/workshops/获取。研讨会次日开展了野外DAS成像演示，演示地点位于路易斯安那州黑鹰市的一段密西西比河堤防。该段堤防已布设总长约2km的光纤电缆，涵盖地表与钻孔阵列，用于实现高空间分辨率的堤防成像与渗漏监测。USACE对该段堤防格外关注，原因是2015年的一场洪水事件中在此处检测到严重渗漏。堤防向陆侧出现的砂沸触发了紧急加固工程：USACE通过沿堤防向陆侧趾部布设一排深层减压井，并在地表砂沸区域铺设砾石垫，阻断了渗流路径。本次DAS成像测试的目的是评估该场地内部侵蚀的范围，并验证DAS技术在此类工程应用中的实用性。
本项目提供本次研讨会中公开可用的DAS数据集。具体而言，数据集包含场地内一条埋设于浅槽中的240m长光纤电缆的DAS时序数据，道间距约为1m。数据采集采用OptaSense ODH4+解调仪，传感标距长度为2m。本次数据采集的震源为NHERI@UTexas的Thumper型振动卡车，该设备可产生垂直动态激励，具体为频率范围5~200Hz、时长12秒的线性调频脉冲（chirp）。本次公开数据集包含沿电缆走向平行布设的15个不同炮点的采集结果。更多实验设计与数据采集细节可参阅数据集附带的README文件。

搜集汇总

背景与挑战

背景概述

该数据集包含来自美国路易斯安那州Black Hawk堤防的分布式声波传感（DAS）数据，采集于2021年10月，使用240米长的埋设光纤电缆和振动卡车震源。数据集主要用于评估堤坝内部侵蚀程度，并测试DAS技术在基础设施工程和地下成像中的应用潜力。