Investigation of Voids under a Spillway using GPR and its Resolution

This paper describes the findings of a project to refurbish an existing spillway on a Category A dam, in particular focusing on the investigation methodology used to identify voids beneath the spillway. The paper presents a summary of the investigation findings and the remediation works completed.

The paper explains how Ground Penetrating Radar (GPR) was used to investigate the presence of voids beneath the spillway. This was used together with more conventional ground investigation as verification. The paper reviews the benefits and limitations of using GPR in identifying void potential beneath spillways. The paper concludes by providing details of how the voiding issue was remediated, outlining the measures employed.