Ground improvement methods (e.g. jet grouting, sand compaction, and deep soil mixing) are popular engineering solutions to increase constructability of the land with poor engineering properties. Testings for quality control and quality assurance are required to ensure the adequacy of ground improvement. Experimental methods (e.g., Standard Penetration Test, Cone Penetration Testing, and sampling and laboratory testing) used to assess such ground improvement are subjected to several limitations such as small sampling volume, time-consuming, and cost ineffectiveness. On a small scale, it’s difficult to examine the integrity of the reinforced columns formed by ground improvement methods. On a large scale, there is no efficient way to assess the average property of the improved ground and the actual replacement ratio of ground improvement.
Geophysical methods are non-destructive, efficient, and cost effective. Applying the geophysical methods in the assessment of ground improvement can greatly enhance the ability to control and ensure the construction quality. This project is aimed to develop an in-hole electrical resistivity imaging method for high resolution detection and a surface wave testing method for overall assessment. The in-hole electrical resistivity imaging method is useful for detecting the diameter and integrity of improved columns, while the surface wave testing method allows quantitative assessment of replacement ratio and averaged property of the improved ground. This research and development may be commercialized to provide product for better quality control and quality assurance of ground improvement. It can also be used to elevate the competitiveness of geotechnical contractors.