Thermo-hydro-mechanical behaviour of sodium silicate-cemented paste tailings in column experiments

The coupled evolution of the main performance properties (thermal, hydraulic, mechanical) of underground cemented paste tailings that contain sodium silicate as chemical admixture are studied by means of unsaturated column experiments. Two columns have been built to simulate the thermo-hydro-mechanical (THM) behaviour of the aforementioned cemented paste tailings (called gelfill. CF) under drained and undrained conditions. The GF columns are cured at room temperature for 28 days. The suction and temperature developments during the hydration process are monitored. When the curing phase has been completed, the cylindrical samples are taken out from the columns to evaluate the thermal, hydraulic and mechanical properties of CF. Uniaxial compressive strength (UCS), saturated hydraulic conductivity, and thermal conductivity tests are conducted. The results show that the mechanical, hydraulic and thermal properties of CF columns are coupled. The UCS values of CF are strongly coupled to heat development, saturation and suction development within the CF. In addition, the UCS outcomes, saturated hydraulic conductivity, and thermal conductivity tests for samples obtained from the CF columns show higher values than small samples. This study has demonstrated that the coupled THM effect on GFs is an important factor for consideration in the designing of cost-effective, safe and durable CF structures. The results presented in this paper will contribute to a better understanding of the THM behaviour of underground CF structures. (C) 2012 Elsevier Ltd. All rights reserved.