中文摘要：

对干燥、饱和以及不同冻融循环损伤作用后的砂岩进行单轴压缩试验,并利用声发射监测其破坏过程,基于破坏过程中的特征应力、声发射变化规律,在室内实验室试件尺度上分析冻融损伤对砂岩渐进破坏过程的影响。研究表明,由于冻融损伤次数的增加,峰值强度及三种特征应力（闭合应力、启裂应力、损伤应力）不断降低;随着冻融循环次数的增大,砂岩渐进破坏各个阶段的AE撞击数和累计振铃计数均不断变小,声发射定位点数也不断减少;冻胀力使部分微孔隙闭合,使裂纹闭合阶段的初始承载力减弱,归一化闭合应力不断减小,冻融损伤劣化作用随着冻融次数的增大越来越弱,因此在裂纹稳定扩展阶段归一化启裂应力和归一化损伤应力呈增大的趋势。

英文摘要：

In this paper, comparative experiments for sandstones under dry or saturated conditions were carried out. Meanwhile, acoustic emission （AE） data were recorded accompanied with each mechanical test. And the effect of freeze-thaw damage on the progressive failure process of sandstone was analyzed based on the change of the characteristic stress and acoustic emission localization in laboratory scale. Ex- perimental results show that the value of peak strength and three kinds of characteristic stresses （ crack close stress, crack initiation stress and damage stress） diminish gradually with the increase of freeze-thaw cycles. The AE hit number, AE accumulative count and acoustic emission localization points at each stage of progressive failure process decreased continuously with the increasing number of freeze-thaw cycles. And finally, the normalized closure stress decreased with increasing number of freeze-thaw cycles because the frost force makes part of micro-cracks closure and the initial capacity of crack weakened. But with the increasing number of freeze-thaw cycles, the deterioration of freeze-thaw damage is weaker and weaker, thus the normalized crack stress and the normalized damage stress have an increasing trend.