Abstract: As the product of municipal solid waste incineration (MSWI), bottom ash can be used as subgrade cushion material by replacing aggregate to achieve the secondary utilization of resources. To investigate its shear strength and deformation properties, triaxial consolidated drained tests were performed on saturated bottom ash with different dry density (ρ_d=1.4,1.5,1.6g·cm^-3) at different curing ages (t=3,7,14,28 d). Shear strength parameters (cohesion and internal friction angle) of MSWI bottom ash are determined via Lambe plane approach. Results unveil that the stress-strain curve of MSWI bottom ash under low confining pressure (100 kPa and 200 kPa) displays strain softening characteristic, and hardening feature under higher confining pressure (200 kPa and 400 kPa). Peak shear strength increases logarithmically with curing age, namely peak shear strength grows rapidly in the early stage (before the first 14 days), and in subsequence slows down. Cohesion and internal friction angle present different trends with curing age: cohesion increases with curing age, while internal friction angle remains almost unchanged.

Key words: municipal solid waste incineration bottom ash, subgrade cushion material, consolidated drained shear test, peak strength, cohesion, internal friction angle