Model Test Research on Bearing Behavior of Pile-Net Composite Foundation in Super Large Area and Deep Soft Soil

Based on the treatment of in-situ foundation, two distinct model tests for pile-net composite foundation in super large area and deep soft soil with different pile spacing were designed to study the bearing behavior of the piles. The result shows: the axial force of pile shaft increases with the growth of embankment filling load and gradually rises down along pile shaft to a certain depth, then slowly decreases afterwards. The velocity of force changing varies from the correlated soil layers, which indicates that pile shaft resistance appears to be unlike in different pile sites; The ratio of pile shaft resistance area to the overall pile length is relatively high while of normal resistance area is smaller,and when the upper load is mainly supported by bearing course on pile end, pile-net composite foundation turns to be friction and end-bearing pile; For each level of loads, both pile-soil stress ratio and load shearing ratio of pile increase modestly, then tend to be steady till the next load level is applying on.