The ground beneath Kingsholm and the ground out toward Quedgeley tell two completely different stories. Near the Cathedral, you hit stiff Lower Lias clay within a metre. Down by the Severn floodplain, you can go six metres through soft alluvium before finding anything competent. That contrast means rigid pavement design in Gloucester cannot follow a one-size-fits-all approach. A concrete slab laid on the stiff clays north of town behaves nothing like one placed on the river terrace gravels near Hempsted. In our experience, the critical step is mapping where the Lias Formation transitions into the Mercia Mudstone Group across the city, because that boundary dictates everything: slab thickness, joint spacing, and whether you even need a stabilised sub-base. We often couple this with test pits to physically verify the transition depth before locking in the pavement section, especially on brownfield sites where historical fill masks the natural strata.
A concrete slab is only as good as the ground it sits on. In Gloucester, that ground changes faster than most engineers expect.
