Consolidation behaviour with and without siphon drainage

To investigate the feasibility and applicability of siphon drainage combined with surcharge loading for the treatment of soft ground, laboratory physical modelling tests were conducted to study and compare the consolidation behaviour with and without siphon drainage. The experimental results showed that the ultimate groundwater level was lowered below the surface of the soil. However, in the test performed without siphon drainage, the ultimate groundwater level was lowered to the surface of the soil. The time required to stabilise the settlement rate can be reduced by 25% in the test with siphon drainage. Whether there was siphon drainage or not, the discharge in the prefabricated vertical drain presented a trend of exponential decline, and the discharge in the test with siphon drainage was approximately two to three times the discharge in the test without siphon drainage. This novel technique is suitable for use in engineering practice based on the analysis of the mechanism because it offers advantages in comparison with other commonly used techniques, including convenient operation, lower cost for maintenance, lower consumption of energy, fewer economic and environmental impacts, and improved consolidation and drainage efficiency of the soil.