Abstract: The calculation method of total earth pressure behind row piles from clayey backfill considering soil arching effect is researched. Against on the single-row retaining piles, the total earth pressure behind row piles which considering the soil arching effect is divided into direct earth pressure and indirect earth pressure. Firstly, in light of the previous researches' weakness, the principal stress rotation theory of retaining wall is used and improved by considering that the value of principal stress is changed after rotating. On this basis, by means of a stress analysis of soil arch element and solving the equilibrium differential equation, an analytical expression for the direct earth pressure is derived. Compared with the analytical solution of predecessors and the measured data, the computed result of the improved method is more consistent with the measured data. Then, the improved method is applied to the indirect earth pressure of the clayey soil, and the analytical expressions for indirect earth pressure and total earth pressure are derived by regarding indirect earth pressure as the integral of the shear stress along the slip surface of the soil between piles. Finally, the change rule of total earth pressure with cohesion and soil-pile friction angle suggested that the soil arching effect mainly affect the lower part of H/3-depth pile body, causing the total earth pressure of this part decrease; and the closer it get to the bottom of the pile, the larger the decrease is. The study can provide a basis for the rational design of row piles.

Key words: row piles, soil arching effect, direct earth pressure, indirect earth pressure