CSI designed and installed an array of fiber optic monitoring points in an area of past and suspected future sand boil development along a section of levee on the Mississippi River. The project included the installation of four approximately 100’ deep vertical monitoring points to observe vertical displacements and temperature changes that may be correlated with the increase in hydraulic pressure associated with sand boils. To minimize the number of cables installed in the borehole, a specialized turn-around detail was designed to allow for a single strain cable to be joined with a single temperature cable in a “U” shape configuration. All four borehole monitoring points are networked together and terminate in a single location where a fiber optic analyzer developed by UC Berkeley for the project is set up to take automated readings. The system is designed to take readings of strain and temperature across the monitored section of the levee, detecting any potential temperature or strain changes in the subsurface. Monitoring at the site is ongoing and is scheduled to continue through 2022 and will hopefully inform future work on levee safety.
Furthermore, CSI has collaborated with the US Army Corps of Engineers to deploy distributed acoustic sensing (DAS), to monitor levee performance through active and passive seismic imaging. At a test site located in Black Hawk, Louisiana, over 2 km of fiber optic cable was installed running along the toe of a critical levee section that has suffered from seepage problems. The installed cable was used to perform seismic imaging using distributed acoustic sensing and a mobile shaker truck provided and operated by NHERI@UTexas. The analysis of the dataset is ongoing, but a portion is available open-access through the DesignSafe-CI Data Depot for community use.
Collaborator: US Army Corps of Engineers, Engineer Research and Development Center (USACE-ERDC), Vicksburg District
Researchers: Peter Hubbard, Andrew Yeskoo, Chien-Chih Wang, James Rector, Kenichi Soga (UC Berkeley), Brady Cox (Utah State University), John Murphy, and Dan Costley (USACE-ERDC)
Domains: Water Infrastructure
Capabilities: Distributed Fiber Optic Sensing (DFOS) – Distributed Strain Sensing (DSS), Distributed Temperature Sensing (DTS), Distributed Acoustic Sensing (DAS)
Publications: TBA!