Abstract: To study the deformation and the failure mechanism of a mechanically stabilized earth (MSE) retaining wall, the effect of the increase of moisture content on the deformation and the failure of the MSE wall is analyzed and studied through the testing on the undisturbed samples collected from the field. The stability of the MSE wall is validated by the numerical simulation. The results show that the shear strength of the MSE wall decreases with the increase of the moisture content. The shear strength of the saturated soil decreases significantly compared with that of the soil at the natural state; and the shear strength of the saturated soil decreases with its dry density. The numerical results show that the stability of the original design meets the requirements, but a large deformation will occur in the middle and at the upper part of the MSE wall under the rainfall infiltration condition. The mechanism of inducing the deformation and failure of the MSE wall is that the wall with a poor drainage deteriorates after the increase of the moisture content in the backfill due to the infiltration of the rainwater in the rainy season, which leads to the increase of the active earth pressure of the retaining wall and then the increase of the lateral deformation in the middle and at the upper part of the retaining wall.

Key words: Mechanically Stabilized Earth Retaining Wall, Moisture Content, Shear Strength, Earth Pressures