Mass permeability concept in the analysis of treated ground with sand drains

Abstract

The macro element method is used to study the effects of improvement of mass permeability by sand drains on a clay foundation. The mass permeability is found to be improved by the sand drains 30 - 300 times that of the non-treated ground. These findings are then applied to two case studies. In the first, where the ground is treated with sand drains under a high applied load it is found that only settlement observations can be used to assess the usefulness of sand drains in this ground. The other case is on coral soils which exhibit high permeability and a high initial undrained bearing capacity compared with common clay deposits. In this ground, the effectiveness of the sand drains is evidenced by a significant decrease in residual settlement.