Abstract: A 3D finite element model was established to calculate the forces and displacements of the double-row pile retaining structure of a foundation pit in soft soil area. The influences of row distance, pile diameter and pile length on the force and displacement of the structure are analysed in order to get the optimal pile row spacing, pile diameter and pile length. Results show that the distribution of bending moment and the displacement of pile are reasonable when the pile diameter is 0.8m-1.0m and the row distance is 3 to 4 times the pile diameter. Increasing the length of front pile is more effective to improving the stability of the retaining structure than increasing the length of back pile.

Key words: deep foundation pit, double-row pile, retaining structure, numerical simulation, influencing factor