中文摘要：

分析了2种岩石试件（一种大理岩方柱试件和一种含圆孔大理岩平板试件）在单轴压缩下试件表面的应变场演化过程，得到了最大剪应变场的特征统计量（方差研随加载的演化规律：S值在试件的均匀变形阶段较小且变化缓慢，在试件的非均匀变形段急剧上升。根据S值的变化趋势，将2个试件的变形破坏过程划分为5个不同的阶段，并给出了5个阶段的代表应变场，总结了各阶段的变形特征。应变局部化是其中一个重要阶段，是联系岩石均匀变形和非均匀变形的“桥梁”。实验结果表明，2个试件的应变局部化开始于加载曲线峰值前非常接近峰值的时刻（方柱试件为99．2％峰值应力处，含圆孔平板试件为92．2％最大载荷处），结束于峰值点。峰值后岩石试件的变形主要表现为弱化带和宏观裂纹的活动。

英文摘要：

The surface strain field evolution of two rock specimens（a marble rectangle column and a marble plate with centre hole） subjected to uniaxial compression, which are observed by digital speckle correlation method, are analyzed. The standard deviation（S） is taken as the characteristics variable of the strain field and the S value of the maximum shear strain field at different loading levels is calculated. It is found that S value is lower and changes slightly during the homogenous deformation stage, where it increases sharply at the heterogeneous deformation stage. According to the variation of S value, the complete deformation and failure process of the two specimens could be divided into five stages. The shear strain fields at typical loading within the five stages are presented; and the deformation field characteristics are concluded. In the first stage, the strain field is homogenous and the loading curve is linear. In the second stage, the slight strain concentration areas or bands appear and the loading curve is slightly curved or continuously keeps linear. The third stage is the strain localization stage, in which several localization bands appear and further are localized. Experimental results show that strain localization of the two specimens in this study begins at a point just before the peak value of the loading curve（99.2% and 92.2% of the peak loads for rectangle column and the centre-holed specimen respectively） and stops at the peak point. The fourth and the fifth stages are at the post-peak of the loading curve, which are the strain softening stage. The localization bands formed in the third stage are interacted and competed in the fourth stage. A final crack appears and the specimen fails along the crack in the fifth stage. Therefore, the deformation of rock after peak value is mainly controlled by the activities of weak bands and macrocracks.