Research On Back Analysis Methods For Piles In Row In Deep Foundation Pit

Piles in row is one of widely used type of retaining structure in foundation pit. It is meaningful to obtain the internal forces of the piles and earth pressure on the piles from the measured horizontal displacement of the pile with back analysis method., In this paper, following work has been done:(1) The back analysis methods applied in foundation pit were summarized and analyzed.(2) The first method applied in the paper is based on Least Square Method. Let the sum of square of difference between calculated horizontal displacements and measured one, a group of equations can be obtained. SVD method was applied to solve the group of equations due to its singularity. However, the method proved to be a failure unacceptable.(3) In another way, a direct research method was employed to solve the problem, but the result is unacceptable..(4) The second method is based on cubic spline method. The key techniques in the back analysis method for foundation pit are the application of the constraint conditions of boundary, smoothing treatment of the measured curve of the displacement and the choice of cubic spline interpolation points., a demonstrated example, one anti-slide pile and two piles of the deep foundation pit were calculated. Agreement between calculation result and measured result verify the feasibility and effectiveness of the method.