Gas permeability measurement on injected soils with cement grout

This paper deals with cement grout injection and its consequences in porous media from an experimental point of view. This injection with very fine cement has to reinforce the medium considered which is a sand extracted from the Loire river (in the west of France). To quantify this improvement phenomenon, measurement of the conductivity decreases after the injection operation is proposed. Injected sand columns are prepared and gas conductivity measurement is done. The aim of this paper is to show gas conductivity results and their interpretation and effects on the injected medium evolution. These demonstrate the very strong decrease between intrinsic conductivity values before and after injection. The reduction ratio is about 10(-4). This allows evaluation of the sample porosity reduction and then the filtration phenomenon. This is responsible for pressure and cement deposition increase in the system voids during soil injection. (C) 2007 Elsevier Ltd. All rights reserved.