Abstract: Based on the reinforcement mechanism and bearing characteristics analysis of compacted pile composite foundation, the soil between piles was divided into different regions according to the compaction effect, the conventional area ratio method was improved, and a composite foundation bearing capacity calculation method that comprehensively considers the area of each compacted zone and the changes in soil bearing capacity was proposed. A theoretical model for the effective compaction zone radius was established by introducing the theory of circular hole expansion and Tresca yield criterion, and was verified by static load tests on a foundation treatment project in Lanzhou New Area, Gansu Province, China. The results show that compared with the traditional area ratio method, the improved method significantly improves the consistency between the calculation results and the measured values, verifying the accuracy and practical value of the improved method method, and providing a more reliable theoretical basis for the design of compacted pile composite foundation.

Key words: compaction pile, bearing capacity of composite foundation, compaction range, cavity expansion theory, static load test