Analysis Of Working Mechanisms Of The Double Direction Reinforced Composite Foundation

In recent years, along with the development of the freeway construction, the treatment of soft soil foundation becomes increasingly important, which triggers the development of various soft foundation treatment technology. The double direction reinforced composite foundation method can be used to integrate the efforts of each components, and for different situations there will be appropriated combinations to treat it, and also it can makes lots of benefits on the finance and technology. For these reasons this kinds of foundation was widely used in the engineering constructions such as railway, freeway, tall building, airport, the project of the back of the abutment strengthening and the widening of existing roads with unfavorable geological conditions. But for its various combination and the difficulty in knowing how each parts works and the date of the soft soil was not exactly close to the real situation, the theoretical values is not in line with the measured values. So based on the research has been done, this article was focused in the theory of pile-soil stress ratio and settlement and consolidation of this kinds of composite foundation.At first the structure of the double direction reinforced composite foundation and how each component of the composite foundation works was discussed.After that the deformation of the reinforced material of the composite ground was discussed and got the rally of the reinforced material caused by deformation of the ground based on the character of the composite foundation. Treating the pile and the soil as linear elastic object and the pile and the soil under the pile cap as a composite pile, got the pile-soil stress ratio by considering the factors of the reinforced material, including the static equilibrium and the compatibility of deformation of the linear elastic object. The calculation result of a case history shows that the calculated value is much close to the observed value based on the presented method.Then the horizontal reinforced cushion was taken into account as an elastic sheet and the soil foundation as a Winkler elastic foundation model. The four-side-supported thin plate which was forced by a unit load was treated as a basic system and the real situation of the sheet was treated as an actual system. And the work that the load on the basic system has done on the displacement of the actual system and the work that the load on the actual system has done on the displacement of the basic system were calculated. Then the formula of the settlement of the reinforced area of the composite foundation was deduced by using the reciprocal theorem. The calculating result of the model test was coincided with the measured result.Finally, the consolidation of the "the horizontal reinforced cushion+granular column" composite foundation was analyzed by the finite differential method and the differential equation of the consolidation was translated to qualitative Rebuilding to be solved. And the method was checked by using a matlab program to calculate a model test and comparing the result to the measured result.