Study Of Settlement Mechanism Of Rigid Piles Compound Foundation Under Embankment

In recent years, the technical of compound foundation has been applied in traffic engineering, and many the problem of compound foundation bearing capacity and deformation have risen. Compared with the stiffness of construction foundation, the stiffness of roadbed is softer, and this is why its capacity of bearing capacity and deformation is weaker. And the study of compound foundation mechanical characteristic is important in engineering and science.In this paper, based on the Numerical simulation with the finite difference software FLAC^3D and FLAC^2D on composite foundation with rigid piles under embankment load and a coastal Practical Project Expressway Tang Shan part, it is analyzed that the influence of geosynthetic reinforcement layer on the composite foundation with rigid piles under embankment, the difference between mechanical character of the composite foundation with rigid piles under rigid load and embankment, and also the effect of reinforcement material on pile-soil stress ratio of piled composite foundation,load of single pile,pile-soil differential settlement and skin friction of pile. The work this paper has done is:Firstly,associated with the theory of rigid pile compound foundation, a numerical model of lab test is built with FLAC3D to simulate the behavior of composite foundation under rigid load and embankment load. By comparing the difference of settlement, pile-soil stress ratio, load participate ratio, the difference of settlement along the pile, the distribution of skin friction on the pile, and we get the conclusion is: So some existing method on the design of composite foundation under rigid load can not be satisfied the one under the flexible load such as embankment.Secondly, with the simulation on the reinforcement composite foundation and no reinforcement one under embankment, contrast their difference of settlement, pile-soil stress ratio, load participate ratio, the distribution of skin friction on the pile, and the difference of settlement along the pile, it can reach following conclusions: geotextile materials decrease the upward "stab" of pile in the composite foundation,increase the pile-soil stress ratio, adjust load sharing between pile and soil, reduce the differential settlement between pile and soil,make pile and soil teamwork embankment composite foundation, Proper spacing can make the geogrid work more fully and enhance the utilization of materials.Finally, based on numerical simulation on coastal expressway of Tang Shan part, stress field and displacement field are contrasted between reinforced foundation and no reinforced under embankment, verify that reinforcement in composite foundation cushion under flexible load can adjust stress field and displacement field of foundation.