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The use of piles installed beneath deep excavations as a means of enhancing the stiffness of the soil and so reducing the spread of movements to the surrounding ground has been investigated. Experimental data were obtained from a series of plane strain centrifuge model tests undertaken at 100g in which three different formation base stiffnesses were modelled. The tests were able to simulate the stress changes that result from the complex propping and excavation sequence associated with top down basement construction. Reductions in horizontal loads of the order of 30% were found when piles were introduced to stiffen the ground beneath excavation formation level. Additionally, significant reductions in heave at the base of the excavation led to overall reductions in both horizontal and vertical ground movements behind the retaining wall. The number of piles was found to have a strong influence on the magnitude of reduction in ground movement, especially with increasing time after completion of the simulated excavation.