Abstract: Pile-raft composite foundation is one of traditional soft ground treatment methods for embankment (such as high-speed railway embankment, etc.) settlement control. However, the researches focused on dynamic responses influenced by different vibration waveform loads are relative little. Large-scale model tests on single pile-raft composite foundation in sand are carried out. The accumulated settlement, pile end and pile side soil dynamic stress ratio, acceleration and speed are measured; and the mechanisms of pile-raft composite foundation influenced by vibration waveforms are briefly discussed and analyzed. The test results show that the accumulated settlement influenced by the M wave is slightly larger than that influenced by the sine wave; while the pile end and pile side soil dynamic stress ratio influenced by the M wave is slightly smaller than that influenced by the sine wave. The acceleration and speed along the pile-raft system are increased with the increasing of loading frequency and loading amplitude. The related research results provide a reference for the theoretical analysis and calculation of pile-raft composite foundation.

Key words: vibration waveform load, pile-raft composite foundation, accumulated settlement, dynamic stress ratio, model test