An experiment is conducted to determine the active earth pressure for soil with limited width behind a retaining wall in translational motion. The test results show that a continuous failure surface of limited-width soil behind a retaining wall passes through the wall toe and a fixed point. Based on the variational limit equilibrium method

a specific equation for the curve of the slip surface is deduced with logarithmic helical curve. The distribution of active soil pressure and soil pressure intensity with a limited width behind wall are derived using thin-layer element method. Comparing with the results of laboratory observations and Coulomb earth pressure

the result by the proposed method is closer to the measured value than the classical earth pressure method. The distribution of the active earth pressure is analyzed under different ratios n of the width to height of the backfill. The results show that the active earth pressure increases with the increasing of n

but approaching to a constant value as n reaches a threshold of limited width of 0.55.