Jet grouting column measurement and soil assessment with electric measurements and cross-hole electric tomography

Abstract

In the context of the construction of the new M3 Bordet-Albert metro line in Brussels, the new Tools Thielemans station will be built near the Gare du Midi. For this purpose, jet grouting work is planned at several sites. Hence, the control of the diameter of the jet grouting columns had to be done in parallel, in constrained conditions, such as, the geographical location in a historical building, the presence of 2m high cellars covering the area of interest, and the length of the columns (over 30 m). The only possible and most reliable methodologies were electric measurements in boreholes to image the reached diameter of the columns and cross-hole electric tomography for determining the electrical resistivities of the in-situ soils and identify heterogeneities in the medium for better parameterizing future jet grouting work.