Study On The Bearing Capacity Of Rigid Long Pile Composite Foundation In The Deep Coastal Soft Soil

There is a lot of deep soft soil distributed in the coastal areas, especially in the vicinity of the river estuaries. The depth can reach 30 meters,even 50 meters.In this area,construction of engineering is also needed for people’s activities of material production and living.But soft deposit of this region normally has high water content and compressibility,low strength,underconsolidated state, as well as large depth of thickness,which makes it become a major problem of foundation treatment.Rigid long pile composite foundation has the advantages of high bearing capacity,obvious control settlement and large treatment depth,which is widely used in coastal areas.However, in the area of deep soft soils,because of lack of engineering practice and corresponding system research,it is necessary to make deep analysis on the rigid long pile composite foundation in deep soft soil.In this paper,the current determining method of composite foundation’s bearing capacity is first summarized,from theoretical calculation to in situ test and then to experience method, exploring the feasibility of using these methods to determine the bearing capacity of rigid long pile composite foundation in deep soft soil.Based on an engineering example, numerical simulation analysis is carried out by using the finite element software ABAQUS, through analysis,the load transfer characteristics of rigid long pile composite foundation in deep soft soil can be obtained.At the same time, the validity of numerical simulation is verified by comparing with the results of engineering example.On this basis,through variable parameter analysis,the load variation law of composite foundation can be obtained.And it can be noticed that the composit e foundation’s bearing capacity can be a very good performance of line elastic properties.By using this feature,the relationship between the characteristics and the parameters of the composite foundation is established.By introducing a simplified calculation formula which is considered the interaction of pile and soil,and through comparing the simplified formula with the engineering example’s result, comparing the simplified formula with variable parameter study’s result,it can be obtained that the simplified formula is suitable for the determination of bearing capacity of composite foundation in deep soft soil. Then the simplified calculation formula is applied to another project, using simplified calculation formula,experience estimate value,and in-situ test value for comparison, it once again verifies that the simplified formula can be used in dterming the bearing capacity of the rigid long pile composite foundation. At the same time, the comparison of the simulation results and the in situ test value can verify the feasibility and accuracy of the numerical simulation.