Analysis and modification of the British Standard BS8006 for the design of piled embankments

The piled embankment is an increasingly popular construction method. The Dutch Design Guideline for piled embankments (CUR 226) was published in the first half of 2010. Several existing models have been analysed to determine the calculation rules used in the Dutch Guideline. The British Standard BS8006 sometimes calculates tensile forces in the geosynthetic reinforcement that differ considerably from other models. For quite thin embankments in particular, BS8006 designs a relatively strong and thus expensive geosynthetic (basal) reinforcement in comparison with other design models. These differences are not always fully understood, leading to uncertainty. This paper analyses BS8006 and demonstrates why it behaves differently from other models. It also examines why this behaviour is different than would be expected. For example, it is shown that calculations using BS8006 are based on a higher load than the actual load. A modification to BS8006 is proposed, which is shown to give comparable results to the German Standard EBGEO for situations where there is no subsoil support. The results of BS8006, Modified BS8006, and the German/Dutch guideline are compared with finite element calculations and field measurements. It is concluded that the results given by the Modified BS8006 are more accurate to those using BS8006.