Study On The Mechanism And Optimal Design Of Top Beam Used In Retaining Piles Of Deep Foundation

Study on the mechanism of the top beam that used in retaining and protecting piles of deep foundations is the uppermost section of this master degree thesis. The classical structure mechanics method and the finite elements analysis software are used to calculate and analyse the internal force of the piles-top beam retaining system. Based on the research of the mechanism of the top beam, the optimal design of piles in row is discussed.The retaining structure types used in deep foundation and these effective conditions, calculation methods of the internal force of retaining structure are reviewed in the paper. As the same time, a model for the calculation of top beam is Cstnblished and used successfully in an engineering instance. The mechanics mechanism of lop beam is discussed by the mcthod of comparing and analyzing the results of calculation. The engineering instance is calculated by ANSYS, the popular software for the finite elements analysis, and the results is same as that calculated by common method. The complex method is introduced and a math model for optimal design is successfully established to design a deep foundation's retaining system in an instance.The top beam can reform the force-bearing mechanism of the retaining piles because the cantilever piles can be fixed by adding a restriction on the top of the piles and the displacement of the piles can be reduced too. As the same time, top beam can harmonize the displacement and force of the piles and avoid the phenomenon of chain failure as one of the piles is destroyed. If the top beam are closed it can work well because the support on the two ends. If the two ends of the top beam are all free it can only harmonize the displacement and force of the piles. The complex method can work well in the calculation of piles optimal design.