Abstract: For the current status of research that it rarely considers the impact of the nature of soil when calculating water and earth pressures, using self-made testing tank as research tool through measurement study by using three types of soil samples with various permeability coefficients, the measured water and earth pressures are compared with the theoretical values obtained by water and earth pressures calculated separately and together method; and the variation laws of pore water pressure and earth pressure are analyzed. The experimental results show that the values obtained by water and earth pressures calculating together method is lower than measured values; but still acceptable under certain conditions. Accompanied by active displacements, it generates negative exceed pore pressure in soil behind wall. Dissipation of negative exceed pore water and transfer of pore water pressure are both affected by permeability of soils which further affect the distribution of water and earth pressures on retaining structures. From the experiment results we can speculate on that the water and earth pressures by calculating together method is reasonable when the permeability of soil reduces to certain level.

Key words: retaining structure, water and earth pressures calculating together, water and earth pressures calculating separately, permeability coefficient, pore water pressure