Abstract: The spatial stress mechanism of circular diaphragm walls persists as a critical research focus in foundation pit engineering. Previous theoretical studies predominantly address axisymmetric loading conditions, with limited investigation of non-axisymmetric loading scenarios. However, eccentric pressure frequently develops in circular foundation pits due to soil heterogeneity and uneven pile loading. To analyze spatial mechanical behavior under non-axisymmetric loading, we deconstruct the column-shell system into vertically oriented elastic foundation beams and circumferentially arranged curved beams using load decomposition principles. We present a rigorous derivation process for calculating internal forces and displacements under circumferential non-axisymmetric loading. The curved beam configuration matches the horizontal geometry of diaphragm walls, enabling simultaneous consideration of spatial arching effects and simplified solution of three-dimensional structural problems while clarifying parameter-deformation relationships. Numerical validation through two case studies confirms theoretical derivations, with cloud distribution plots illustrating circumferential and vertical load-sharing coefficients. Results demonstrate that circumferential stiffness predominantly governs soil-water load resistance in circular diaphragm walls.

Key words: circular foundation pit, load-sharing method, curved beam with elastic foundation, vertical foundation curved beams