Expansion is an important strategy to increase the capacity of a landfill

but the induced deformation by expansion can threat the stability of the landfill and its internal structure. Synthetic municipal solid wastes (MSWs) which exhibited engineering characteristics similar to MSW in China were developed

and a series of centrifugal model tests on the deformation of expanded plain-type landfill under self-gravity stress was performed. The settlement of landfill under self-gravity stress decreased as the MSW age increased with a maximum settlement of approximately 20% of the initial landfill height. Differential settlement of the interface between the old landfill and the new landfill decreased with the increase of old landfill MSW age. The maximum value of horizontal displacement on the interface occurred under the slope shoulder

and increased with the increase of slope ratio and decrease of filling age. The engineered berm restricted the settlement of the old landfill before expansion

but the settlement restriction was weakened as the height of landfill increased after expansion. It might induce large difference of the horizontal displacement on the interface. The results of the tests are slightly larger than those of one-dimensional settlement calculation of the landfill

and can provide reference for the expansion and liner system design

stability assessment and landfill operation.