Numerical Sim Ulation On Differential Settlement Of At Highway Expansion Project On Soft Soil Composite Foundation

In China, composite foundation is used widely as a foundation approach in highway expansion project on soft soil. However, due to the inherent technical complexity of soft soil, the problem involved in expansion project on soft soil much more than the new road on soft soil. How to use composite foundation in the highway expansion project is still to be explored further. Along with the growing of highway expansion, the study on the composite foundation in highway expansion project on the soft soil has important practical significance.Based on the finite element analysis software ABAQUS, the paper has do the finite element analysis of the interaction between the old and new embankment of the expansion project. And study the effect parameters of PHC pile composite foundation, and also analysis the effect of geogrids.First of all, according to the existing literature, do a lot of surveys and studies about the composite foundation approach of the existing highway expansion project, and explain its key technology anf the treatment effect, and also analysis the merits and problemsSecondly, based on the finite element analysis software ABAQUS, compile the subroutine of Duncan-Chang non-linear constitutive model, analysis the influence of new embankment as an additional load to the old embankment, including differential settlement and horizontal displacement of new embankment, the maximum settlement and horizontal displacement of the new embankment, the stress state of the embankment and foundation of highway expansion project and so on.Finally, by the finite element analysis, this paper has give a detailed analysis about the law of deformation on the PHC pile composite foundation. And also the design parameters of PHC pile composite foundation used in high expansion are analyzed, including the pile length, pile spacing, pile diameter, modulus of cushion; the same time, geogrid plus PHC pile composite foundation approach is discussed.The results show that, PHC pile composite foundation using in deep soft soil and bridge section is a technical and economic measure, and the joint geogrid can effectively control the expansion of the lateral displacement of the new embankment.