Experimental study of the effects of moisture content on the mechanical properties of sandstone under uniaxial compression

Water inside the micropores has a tremendous influence on the mechanical properties and damage patterns of rocks. To investigate the effects of different moisture contents on the cracking behavior of sandstone under different compression conditions, four groups of sandstone samples with moisture contents of 1.00%, 2.50%, 3.50% and 4.50% were used for uniaxial compression and cyclic loading-unloading experiments. The results show that the compressive strength and elastic modulus decrease with the increase of moisture content. The ultimate failure patterns for samples are all shear failure modes with different dip angles. In the unloading experiments, the dissipated energy and residual strain decreases with the increase of moisture content during the unloading stage with low stress and increases obviously during the unloading stage with high stress.