Microanchored fiber-optic DSS in boreholes allows strain profiling of the shallow subsurface

This is a Preprint and has not been peer reviewed. The published version of this Preprint is available: https://doi.org/10.1038/s41598-021-88526-8. This is version 2 of this Preprint.

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Authors

Cheng-Cheng Zhang , Bin Shi, Song Zhang, Kai Gu, Su-Ping Liu, Xu-Long Gong, Guang-Qing Wei

Abstract

Vertical deformation profiles of subterranean geological formations are conventionally measured by borehole extensometry. Distributed strain sensing (DSS) paired with fiber-optic cables installed in the ground opens up possibilities for acquiring high-resolution static and quasistatic strain profiles of deforming strata, but it is currently limited by reduced data quality due to complicated patterns of interaction between the buried cables and their surroundings, especially in upper soil layers under low confining pressures. Extending recent DSS studies, we present an improved approach using microanchored fiber-optic cables—designed to optimize ground-to-cable coupling at the near surface—for strain determination along entire lengths of vertical boreholes. We proposed a novel criterion for soil–cable coupling evaluation based on the geotechnical bearing capacity theory. We applied this enhanced methodology to monitor groundwater-related vertical motions in both laboratory and field experiments. Corroborating extensometer recordings, acquired simultaneously, validated fiber optically determined displacements, suggesting microanchored DSS as an improved means for detecting and monitoring shallow subsurface strain profiles.

DOI

https://doi.org/10.31223/X57611

Subjects

Earth Sciences, Engineering

Keywords

Dates

Published: 2021-03-22 11:04

Last Updated: 2021-04-28 18:17

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License

CC BY Attribution 4.0 International

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