Damage analysis of standstone in different moisture state

By experimenting on the sandstone of different moisture content in acoustic emission of uniaxial compression, the sandstone's damage characteristics in different moisture content and different damage symptoms are contrasted. The results prove that the damage curve is very smooth in the dry status and low-stressed stage; however the damage curve is rather steep when the damage increases sharply, and the damage curves rise by more than one step; in the natural state of water, the damage curve is growing rapidly firstly, then it turns into the tranquil period in which the damage curve is relatively smooth, it increases when it is close to destruction, but the amplitude of increasing is lower than that of the dry state; In the saturated state, at the beginning the damage curve increases sharply in low-stressed stage, then it brings into a longer tranquil period, the damage curve changes less near destruction, the rocks hardly have any damage symptoms. The conclusions are : with the increasing of sandstone moisture content, the acoustic emission distributes in the moment of sandstone destruction intensively; the less obvious the former symptoms of damage is, the more obvious the brittle failure during destroying will be; the damage of symptoms in the acoustic emission parameter is more reasonable than the sandstone damage of strain parameters.