Mechanical properties of sandstone after cyclic drying and wetting

Cyclic wetting and drying usually occur in rockmass for some reasons such as water level variation, which is fairly harmful to its long term safety. A series of uniaxial and triaxial compression experimental tests on sandstone under cyclic drying and wetting have been carried out. The corresponding complete stress-strain curves are obtained, and characteristics of deformation and failure are analyzed. Compared with the dry specimens, elastic modulus, cohesion, internal friction angle, uniaxial and triaxial compressive strength of the specimens under "dry-saturation" cycling were all decreased to some degree. It is found that all mechanical parameters have a relatively sharp decline after the first time saturated with water, and thereafter, decrease gradually followed by an increase of cycling times. The rock samples become more ductile after cyclic drying and wetting.