Analysis of Effect of CFG Pile Composite Foundation Pile Spacing on Embankment Stability Based on Centrifugal Model Tests

The cement-fly ash-gravel (CFG)pile composite foundation played an important role in increasing the soft soil foundation strength and stability, and decreasing the foundation settlement etc, because that the pile strength potentiality could be fully developed and soils bearing capacity also could be fully utilized. The analysis of interaction rules among flexible embankment, CFG pile, soils, and cushion was the key factor to keep the CFG pile composite foundation stability. Three centrifugal model tests with different CFG pile spacing were conducted to research the effect of pile spacing on the CFG pile composite foundation stability, and the surrounding soils press, pile top press, pile strain etc were measured. It was shown that the embankment instability modes were different with CFG pile spacing. CFG pile composite foundation stability was affected by pile spacing, pile quality, and embankment height etc. Instability of CFG pile composite foundation was complicated, but not only for pile or soil destroyed.