In-situ Test of Pile-soil Stress Ratio of CFG Pile Composite Foundation under Embankment Load

In-situ tests on pile-soil stress ratio of CFG pile composite foundation under earthfill embankment in Dexing-Nanchang freeway were carried out.The test results of pile-soil stress ratio of CFG pile composite foundation with different pile spacings in embankment filling in construction and in static loading test with rigid board were analyzed.The regularities of pile-soil stress ratio varying with load and time were discussed.The results show that(1) The variation of pile-soil stress ratio under embankment load is quite different from that under rigid load,the pile-soil stress ratio which tested in embankment construction is much less than that under rigid load.(2) The pile-soil stress ratio increased quickly when the height of soil was within 2.0 m.With a higher soil-filling height within 2～3.5 m,the pile-soil stress ratio decreased rapidly.When the soil-filling height was higher than 3.5 m,the stress ratio started to go up gradually,and then fluctuated.The values of pile-soil stress ratio fluctuated and stabilized in the range of 1.18～2.26 at last,and changed hardly with time.(3) The pile-soil stress ratio decreased with the increase of pile spacing,and the pile-soil stress ratio changes tiny when the pile spacing increased to a certain value.