The Research Of Mechanism On Settlement And Method On Settlement Calculating For Bonding Material Pile Composite Foundation Under High Embankment

In recent years, the pace of development of China’s highway infrastructure is extremely rapid. The composite foundation has been more and more widely used which has a good practicability and economy. The embankment load of composite foundation was called composite foundation under flexible foundation, in order to distinguish with the composite foundation under rigid foundation. A large number of studies show that, there were great difference between the composite foundation settlement variation of high embankment(under flexible base) and that of composite foundation under rigid base, it will make the result unsafe if the settlement calculation theory of composite foundation under rigid base applied to high embankment composite foundation, many domestic and foreign scholars have done related research, but most of them were based on the soil between piles for ideal homogeneous assumption, which is not consistent with the actual situation and decreased accuracy. Therefore, based on the previous studies, study on the calculation methods of composite foundation under high embankment will be launched in this thesis by combining with its mechanism.First of all, combined with the recent research of domestic and foreign scholars on the high embankment composite foundation, the paper did a further exploration of the deformation mechanism of bonding material pile composite foundation under high embankment by analyzing different aspects, such as action mechanism, load transfer mechanism, and characteristics of deformation, from the common action system perspective. With flexible pile and rigid pile composite foundation as an example, this paper introduces several kinds of calculation method on settlement of composite foundation under high embankment.Second of all, when there was no relative slippage at the interface of piles and soil in the reinforced zone of composite foundation, soil arch effect and stratification of composite foundation were considered, and hypothetic displacement modes between soil and piles are proposed, the analytical equations of settlement of piles and soil in reinforced zone on composite foundation under embankment loads are thereby deduced; when there was relative slippage at the interface of piles and soil, the displacement modes was reformed, and soil arch effect and stratification of composite foundation were considered, and the theory of spherical reaming was used to calculate upward penetration displacement which happened in substratum piles piercing, a method of calculating the settlement in reinforced region of bonding material pile composite foundation considering the relative slippage between piles and soil in stratified foundation was thereby developed.Finally, combined with the engineering example, the calculated results by using analyzing method in this paper were compared with field test results and it by using existing means, and the rationality and feasibility of calculated method considering layering foundation of reinforced zone in bonding material pile composite foundation under high embankment was verified.