Project title: Developing a Toolkit for Imaging Shallow Karst
Researcher: Alex Braun
A large portion of Ireland and the world are underlain by limestone bedrock, which is susceptible to karst weathering. The dissolution features formed in the process present a unique geotechnical hazard, which can lead to costly damages or loss of life. Thus, ground investigations are usually complete, which include indirect and direct survey methods to minimize risk. This project focuses on the application of geophysics to map underlying dissolution features, which provides comprehensive data at low cost. In particular, we are interested in maximizing the detection of a probable air-filled void or depression feature, which are the most problematic karst features. At the present moment, there is no specific guidelines on the investigation and constructions above karst landscapes in Ireland. The geophysical methods used in this project are GPR, resistivity, microgravity, seismic refraction, and surface waves. The research includes a literature review of published work, a case study of geotechnical projects which encountered karst, geophysical modelling, and four survey sites to carry out our own investigations. This research will develop a new methodology of optimized geophysical techniques to maximize the detection of near-surface karst features, which will reduce cost and risk in construction projects.