Abstract: Effect of wetting-drying on soils derived from granite is significant; and it causes collapse of caved walls or damage of engineering facilities. Slaking test and consolidation test with 6 wetting-drying level treatments are performed to identify effects of wetting-drying paths and consolidation pressures on relative deformation ratio. The results show that crack is the main reason for the relative deformation ratio at dehumidifying stages, while relative deformation ratio depended on matric suction, slaking property, and soil texture at humidifying stages. Relative deformation ratio increased with consolidation pressures especially in excess of preconsolidation pressure of 103.06 kPa. The relationship between coefficient of compressibility and initial water content conformed to an exponential function, and coefficient of compressibility increased rapidly with the initial water contents beyond 25%. Laterite layer ① had the most range of compressibility coefficient （0.15-0.62 MPa-1） with the average value of 0.31 MPa-1. The mechanism of caved wall collapse also is revealed from non-uniform settlement due to wetting-drying effect. Some countermeasures of engineering facilities in disintegration erosion area against nonuniform settlement are discussed. The obtained results could offer references to engineering maintenance and slope disintegration erosion control.

Key words: nonuniform settlement, drying-wetting effects, coefficient of compressibility, relative deformation ratio, slope disintegration