Construction of Road Embankments over Very Soft Soil Using Band Drains and Preloading

As part of a new national road being constructed in South Africa an embankment was built over a deep deposit of very soft soil. To enhance stability the embankment was built in several stages and in order to reduce the time required for consolidation between stages, band drains were installed in the foundation soils. The soils were instrumented to monitor pore water pressure and settlement. The results of the monitoring phase showed that the band drains were effective and operated as designed. This paper presents the results of the monitoring and discusses the prediction of degree of consolidation from settlement readings as opposed to pore water pressure along