Contribution of Electrical Resistivity Tomography to the Anticipation of Potential Disasters: Case of Pipe Ramming Works Under Road Embankments

---

Résumé

Throughout Burkina Faso's road network, some roadways have experienced subsidence or collapse following pipe ramming works conducted for the laying of pipes such as drinking water supply networks.When such works are conducted, it is difficult to make a diagnosis of the properties of the formations underlying the road embankment because a destructive sounding would lead to expensive and tedious repairs.In this present study, a geophysical method, namely electrical resistivity tomography has been used to image the structure and the geometry of these formations so as to anticipate potential disasters.Four electrical resistivity profiles were conducted near the insertion and receiving pits, parallel to the national road N°4, at the exit of the capital Ouagadougou.The strategy of prospection has allowed to image down to an investigation depth of approximately 10 m.The study showed that at an average depth of 2 m, an environment of very low electrical resistivity (about 50 ohm.m) is observed in a very resistant environment.This conductive environment corresponds to the presence of a porous and very wet material which extends laterally and in depth under the roadway, and which can lead to a subsidence or a collapse of this roadway on the surface.

Mots-clés

Tomography, Roadways, Geophysics, Burkina Faso