Instrumented Pile Load Test Using Distributed Fibre Optic Sensor: Automation in Data Processing

Distributed Optical Fibre Strain Sensing (DOFSS) instrumented pile load test yields a continuous strain profile along the pile shafts by Brillouin Optical Time Domain Analysis (BOTDA) technique, then further analyse to infer load transfer function (p-y curve) and shaft friction (t-z curve). The process of converting the raw DOFSS strain data to the meaningful pile load test report is however not that straightforward. It requires the process of trimming, positioning, flipping, averaging, curve fitting and other computations; often done manually and can result in inconsistency and interpretation errors of pile load performance. This paper aims to propose a standardised way of processing DOFSS data through an automated program incorporating the Finite Element Method (FEM). The developed algorithm was tested against several instrumented pile load tests with computational processing time in a matter of seconds. The interpretation of pile load-bearing capacity is compared between DOFSS and numerical analysis.