| Compared to the single rank of piles,the double-row piles supporting structure has the advantage of large integrated stiffness,strong supporting capacity and the ability to overcome the difficulties arisen from the restrict of the property line,so that it has been widely used in the deep foundation pit.However,the understanding of the mechanism of double-row piles is not very clear at present,and its method of calculation still to be improved.Therefore,on the basis of summarizing the research status of double-row piles supporting structure,the following research work has been done:(1)The advantages and disadvantages of the existing calculation model were analyzed,and a double-row piles calculation model based on piles-soil consistent deformation theory was proposed.In the model,the excavation load of the foundation pit was taken as the direct,load of the supporting structure,the interaction between piles and soil was simulated by springs,and the earth pressure of piles-soil consistent deformation was taken as indirect load,which can avoid that the earth pressure distribution was pre-assumed and the shear slip surface was considered in the limit state analysis,so that the results obtained by the incremental method are more realistic.(2)Combined with bar system FEM of elastic foundation,the corresponding calculation principles and formulas of the model were presented in this paper,and the calculation program of double-row piles supporting structure based on MATLAB was compiled.(3)The calculation method of this paper,the normative method and the ABAQUS finite element were used to calculate the example respectively.The results of this paper method are closer to the finite element results,which proved the reasonability of the model and method in this paper.(4)By finite element numerical simulation,the influence of structural design parameters on support performance of double-row pile is explored.The influence of row spacing,embedded depth,pile diameter,pile spacing and beam stiffness on the support performance of double row pile was analyzed,and the reasonable value ranges of the parameters was obtained.According to the influence law of row spacing,embedded depth and pile diameter,the calculation models for "large row spacing","longer pile in front row and shorter pile in back row" and "larger diameter pile in front and smaller diameter in back row" were put forward.On the basis of the original calculation method,the calculation methods of the above different calculation models were given. |
PDF Full Text Request