Cross-Borehole Resistivity Tomography below Foundations in Covered Karst

A021 CROSS-BOREHOLE RESISTIVITY TOMOGRAPHY BELOW FOUNDATIONS IN COVERED KARST AUTHORS Abstract 1 This paper presents a case study conducted below building foundations in a karstic area at Tournai (Belgium). Geophysical investigations were carried out to map the complex geometry of the subsurface. Twenty-three cross-borehole resistivity panels with multiple arrays were performed on the site. Data were inverted with Res2DInv ® software. Tomographies give a good overview of the competent bedrock geometry and also allow to delineating covered weathered limestone. Introduction The investigated building is situated at Tournai in the south-west of Belgium. Several collapses from 2 to 3 meters in