Near-surface methods in the geotechnical industry: Challenges, opportunities and limitations

Summary The geological risk is a major unknown in large-scale infrastructure projects and frequently leads to cost overruns and major delays. Geophysics and remote sensing methods, when properly combined with traditional intrusive techniques, provide value to the geotechnical industry by reducing this risk. Continuous improvement of accuracy and resolution within both remote sensing and geophysics opens up to new innovative applications in the geotechnical industry. We present three examples. Integrating airborne electromagnetics and geotechnical drillings by virtue of machine learning provides dynamic, high-resolution depth of cover / bedrock topography 3D models. Various high-resolution ground geophysics methods identify buried objects that pose a risk to construction works. Finally, satellite-based radar interferometry with some mm / year accuracy provides project owners with settlement monitoring before, during and after construction works, supporting point measurements with traditional methods. Satellite-based, airborne, and ground-based methods have their individual strength and weaknesses. The challenges that projects encounter vary with different phases, thus the key to success is using the right method at the right time.