Gas injection tests on sand/bentonite mixtures in the laboratory. Experimental results and numerical modelling

Gas flow through clay barriers is investigated on the basis of laboratory work and its corresponding modelling. The formation of preferential paths is achieved in dipole test using needles, and this requires specific treatment of the injection and extraction systems in the numerical simulation. The results of the test are difficult to interpret and are also influenced by the testing protocol. The modelling uses a coupled hydro-mechanical model which considers the possibility of opening of gas flow preferential paths assuming heterogeneous distribution of properties. The calculated results show an encouraging agreement between model predictions and measurements.