Accelerated consolidation of the fill material is often considered to be a critical element on many civil engineering projects. Design engineers are often required to reduce consolidation time in order to meet demanding construction programs. Ashton Moss is a commercial and leisure development near Manchester where large volume of fill material was used and fast consolidation was one of the critical design requirements. Total and differential settlement were the prime targets of this design. During design, various thicknesses of layers were considered to achieve the required rate of dissipation of pore water pressure from the fill material. This paper explains the geosynthetic drainage technique that was chosen to provide drainage and reinforcement. In order to reduce surcharge heights and accelerate consolidation of the engineered fill comprising selected imported construction, demolition and excavation waste (CDEW), multiple geocomposite drainage layers were installed horizontally within the fill at one metre vertical spacing. Fildrain 7DD geocomposite drainage layer with double cuspated drainage core was used to maximize drainage input from the CDEW fill material and achieve the required rate of consolidation. The analysis is important for designers who are considering innovative fill consolidation design solutions using geosynthetic alternative to traditional granular drainage layers.
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