Semester of Graduation

Spring 2023

Degree

Master of Science in Civil Engineering (MSCE)

Department

Civil and Environmental Engineering

Document Type

Thesis

Abstract

Innovative sensors can provide new capabilities to monitor and understand the behavior of soil, rock, and geo-structures and help geotechnical engineers make informed decisions about the construction and maintenance of geo-structures. This study introduced, calibrated, and validated one such sensor, the Surface Stress Sensitive Film (S3F) point sensor, for both normal and shear stress measurements in soil along the soil-structure interface. The measurements of S3F sensor rely on the deformation of an elastic film that is monitored by a floating element embedded in the elastic film. This sensor provides measurements of the 3D deformation of the film which are converted to normal and shear stress measurements using an a-priori calibration. The calibrations of the S3F sensor were performed considering the effect of the loading areas, loading and unloading conditions, and soil particle sizes. Then, the performance of the S3F sensor to accurately measure the normal stresses in the soil tank and shear stresses at the soil-wooden block interface under static tension and pull-out conditions was evaluated. It was found that the normal stress calibration curves depended on the sizes of the loading areas due to the stiff housing boundary effect. However, the shear stress calibration curves were independent of the loading areas. The S3F sensor showed its ability to measure normal stresses in three different types of soils (Ottawa 20/30 sand, Ottawa 50/70 sand, and Sil-Co-Sil silica silt) and to measure the shear stresses at the soil-structure interface, which match well with the theoretical values of normal and shear stresses. The S3F sensor has the potential for stress measurements for soil-structure interactions in shallow and deep foundations, tunnels, buried pipes, and retaining systems.

Date

4-11-2023

Committee Chair

Lin, Hai

DOI

10.31390/gradschool_theses.5722

Available for download on Sunday, March 29, 2026

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