Development of soil-rock total sounding for production control of dry deep mixing columns

Larsson, S., Nilsson, G. and Jelisic, N. (2021) Development of soil-rock total sounding for production control of dry deep mixing columns. Deep Mixing - An Online Conference, DFI Deep Foundation Institute. 8 p.

Abstract: The most common method for production control of lime-cement columns (the Nordic dry deep mixing method) is the column penetration test. For columns longer than 8 m, it is recommended to pre-bore the column in the centre because the column penetration test probe can easily deviate out of the column. This pre-boring is normally performed with soil–rock total sounding. Conceptually, there should be a correlation in the sounding force between the methods. If this correlation is sufficiently good, it should instead be possible to use the soil–rock total sounding, which is much easier and faster than the column penetration test. If the soil–rock total sounding indicates poor quality of the column stiffness, the column penetration test can be used selectively. The main objective of this study was to investigate and verify previous tests and to quantify the correlation between the two methods. The results show that the correlation is significant but that the variability is large, as expected.