关键词: 深基坑, 排桩支护, 矩阵分析法, 内力与变形, 支撑轴力

Abstract: The traditional theory for plane pile support computation is limited to calculating the internal forces and deformations of the pile body on the supporting plane. It does not address the calculation of axial forces on the xoy horizontal plane support. Deriving a true three-dimensional solution is overly complex, often necessitating reliance on finite element software for three-dimensional model calculations. This study builds upon prior research to derive displacement and force matrix solution equations for the support surface, accounting for excavation processes, pile-soil-crown beam-support structure interactions, and the calculation method of axial forces on the xoy horizontal plane. These equations are solved using a FORTRAN program. Based on an engineering project, this study analyzes and compares the behavior of crown beams, waist beams, support piles, support displacements, and internal forces under spatial effects with the finite element method, LiZheng’s deep foundation pit calculation results, and monitoring data processed through nonlinear regression. The results indicate that the crown beam displacement, calculated using a matrix analysis method that accounts for the excavation process and pile-soil-crown beam-support structure interaction, exhibits a pronounced spatial effect. This effect is most prominent near the corner of the foundation pit. Within approximately one-fourth of the distance from the pit angle along the span of the crown beam, the pile spacing can be increased appropriately. The axial force on the support at the xoy horizontal pit angle is significantly lower than that at the center, aligning well with the monitoring data. Targeted optimization of the support section and reinforcement calculations can lead to reduced engineering costs. The displacement of the crown beam and pile body aligns well with the monitoring data and the results computed by LiZheng software, further validating the method’s rationality and feasibility. This can serve as a novel optimization design approach.

Key words: deep foundation pit, row pile support, matrix analysis method, internal force and deformation, supporting axial force