Discrete-element study of the swelling behaviour of Na-montmorillonite

作者：Anandarajah A^*; Amarasinghe P M

来源：Geotechnique, 2013, 63(8): 674-681.

DOI：10.1680/geot.12.P.012

• clays
• discrete-element modelling
• expansive soils
• mineralogy
• numerical modelling
• pore pressures

The roles of crystalline and osmotic swelling in the overall swelling of a volume of clay are poorly understood. In this paper, the swelling behaviour is simulated using the discrete-element method (DEM). The interparticle forces include mechanical, attractive (van der Waals), and repulsive (double-layer and interlayer) forces. Except for the interlayer repulsion, rational force-displacement relations had been established in previous publications. A systematic molecular dynamic study has recently been completed to establish the interlayer force-displacement relation. These relations are synthesised into a DEM study in the present paper. Numerical experiments are conducted by first forming dry powder assemblies and then saturating them under constant volume. The changes in internal fabric and the swelling pressures developing on the walls are evaluated. It is found that particles expand and fill up the interparticle pore spaces. The predicted relation of void ratio against swelling pressure is found to be reasonably close to that experimentally measured by others in the past. The results also indicate that the crystalline swelling influences swelling pressure values only when the void ratio is smaller than a certain value.

• 出版日期2013-6