Abstract:

Cyclic wetting and drying usually occurs in rockmass for some reasons such as water level variation, which is fairly harmful for 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 strengths of the specimens under “dry-saturation” cycling are all decreased to some degree. The general trend is that all mechanical indices have a relatively sharp decline after the first time saturated with water; and thereafter, decrease gradually followed by an increase in cycling times. The rock samples become more ductile under cyclic drying and wetting. Sandstone peak strength increases along with the increasing of confining pressure. The effect of confining pressure on peak strength is greater for dry specimens than for “dry-saturation” cycling specimens.

Key words: rock mechanics, experimental study, mechanical properties, cyclic drying and wetting, deformation, strength