Comparative analysis of model tests on different types of composite foundations

Nine groups of model tests on the geocell-reinforced cushion, bag-sand well, gravel pile and flexible pile composite foundation are completed to analyze the consolidation effect of different types of composite foundations based on the similarity theory. Some conclusions are drawn as follows: (1) the inclusion of horizontal reinforcement can spread the upper load and raise the bearing capacity, and the reinforced effect of geocell is superior to that of geogrid; (2) the effect of pile groups cannot be neglected when analyzing composite foundation with piles and their bearing capacity is superior to that of horizontal reinforcement composite foundation obviously; (3) the volatility of bearing capacity of piles and soil changes under different loading ranges, and that under single-pile loading range is higher than that under three piles and seven piles. The pile-soil stress ratio of the pile head of gravel pile composite foundation is larger than that of gravel pile + geogrid composite foundation. The smallest is gravel pile + geocell composite foundation, but for the foundation of flexible pile types is flexible pile + geocell composite foundation larger than flexible pile + geogrid composite foundation, and the smallest is flexible pile composite foundation; (4) the pile-soil stress ratio of bottom pile of bag-sand well and gravel pile composite foundation is about 1 and for the flexible pile composite foundation it is much larger and the largest value is about 24; the pore-water pressure is larger and the velocity of dispersion is faster in shallow foundation than those in deep foundation of pile. The pore-water pressure, and that is bigger of piles composite foundation is larger than that of soft soil foundation and geocell-reinforced composite foundation, and the outflow velocity of bag-sand well and gravel pile composite foundation is faster than that of flexible pile composite foundation.