Experimental Study on Pile and Soil Stress of Cement Fly-Ash Gravel Pile Composite Foundation During the Process of Filling Embankment

During the process of filling and embankment filling is completed, pile top stress and soil stress between piles of CFG pile composite foundation has been not very clear. By the field test of the different parts' pile top stress and soil stress between piles of the CFG pile composite foundation of new second double Lanzhou-Xinjiang line DK821 + 600 ∼ DK821 + 900, get the different parts' stress value with the embankment height. It's known with the filling embankment height increasing that the different parts' pile top stress and soil stress between piles gradually becomes bigger, but the growth rate is not the same. The closer away from the pile center, the greater the rate of the stress increment, the farther away from the pile center, the smaller the rate of the stress increment, but added value is not linear with distance. The pile top stress and its rate of increase is much larger than the soil stress between piles and its rate of increase. The pile-soil stress ratio increases gradually with the filling embankment height, the maximum range of the pile-soil stress ratio is between 5.6 to 8.1. Meanwhile, as the filling embankment height increases, the pile bearing the load percentage of the total load increases, while the soil between the piles bearing the load percentage of the total load gradually reduces, more and more the load increment diverts to the pile top.