Calibration of a coupled model to predict the magnitude of suction generated by osmotic technique with PES membranes and temperature effect

Using the osmotic technique to control soil suction requires a reliable correlation between concentration of soluble polyethylene glycol (PEG) and suction generated under isothermal condition. Experimental data to establish such correlation can be found in the literature but they tend to be incomplete and mainly pertain to cellulose membranes. Recent research has shown that polyethersulfon membranes (PES) are a better alternative than cellulose membranes in terms of durability and reliability. However, no complete calibration dataset is available for applying the osmotic technique to account for use of PES membranes and effects of different PEG molecular weights, concentrations and temperature. This study intends to fill such a gap by providing reliable and comprehensive experimental data. The response of PES membranes was investigated over a range of temperature varying from 20°C to 40°C and the results were used to calibrate a coupled model that allows a better prediction of suction generated by the osmotic technique. The influence of PEG molecular weight has been evidenced and can be incorporated in the model.