Study On Settlement And Optimum Design According To Settlement Of Composite Foundation

Composite foundation is an artificial foundation composed of basal body and reinforced body, in which some soil is reinforced or replaced, or some reinforced materials are set in the progress of foundation treatment. The essence of composite foundation is that the superimposed loading is shared by the basal body and the reinforced body jointly and directly. Composite foundation has been widely applied in the civil engineering, but its study on settlement is relatively fall behind the engineering practice. Settlement of composite foundation is especially important when treating deep soft foundation, so it is quite necessary to study on settlement calculation and optimum design according to settlement. Based on the known research findings, research on settlement and optimum design according to settlement of composite foundation under rigid foundation has been systematically carried out in this paper.Based on the mechanism of load transfer and deformation of discrete material piles, the relationship between stress and strain of pile and soil is analyzed. Compression layer is divided into 3 different sections: expanding, un-expanding and substratum according to deformation forms, and each section is calculated by different method. By this method, the settlement calculation of discrete material piles composite foundation has been improved. And factors influencing the settlement are analyzed in this paper.Modified formula of composite modulus is deduced in which shear deformation method is introduced and the influence of pile length and tip resistance on composite modulus is considered. Then factors influencing the composite modulus are analyzed.There exists an effective length in the flexible pile under loading. The calculation formula of effective length of pile is deduced by assuming skin friction form. Considering the influence of effective length of piles, compression layer is divided into 3 different sections: top to effective length, effective length to bottom of pile and substratum. The settlement of composite foundation is the sum of these three sections. By this method, the settlement calculation of flexible piles composite foundation has been improved.In order to improve the stress distributions, it should have the upper penetration into the cushion. The deformation of pile can be ignored because of its large rigidity. So the total settlement of rigid pile composite foundation is chiefly composed of the upper and lower penetration and substratum. According to the equilibrium equation,...