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对大红山铜矿的3种岩石的试样进行了劈裂拉伸(巴西法)试验和单轴压缩试验,研究了岩石的变形特性。劈裂试验中在试样中部相互垂直的方向上粘贴了电阻应变计测量试样的变形。结果表明,在劈裂试验条件下,两种岩石均出现垂直于加载轴线方向所获得的拉伸弹模小于平行于加载轴线方向所获得的压缩弹模的现象。与单轴压缩下试样出现破裂、扩容的破坏特征相比,劈裂拉伸下试样的变形特征为接近峰值时变形曲线斜率会逐渐降低,达到峰值应力后则很快出现数值很大的拉伸变形,直至试样破坏。劈裂拉伸循环加卸载试验发现,大多数试样的拉伸卸载变形大于加载变形,致使残余变形的数值为负值,称之为反向残余变形。此现象与连续介质变形行为的预期不符,至今未见类似报道。反向残余变形是否具有普遍性及其影响,应该开展更多研究。
The specimens of three rocks in Dahongshan Copper Mine were subjected to splitting (Brazil method) test and uniaxial compression test to study the deformation characteristics of the rock. In the splitting test, deformation of the strain gauges was measured in a direction perpendicular to the center of the test specimen. The results show that under the condition of splitting test, both the rocks show a phenomenon that the tensile modulus obtained perpendicular to the loading axis is smaller than the compression modulus obtained parallel to the loading axis. Compared with the failure characteristics of rupture and expansion of uniaxial compression specimens, the deformation curve of the specimens under the split tensile test will gradually decrease when the deformation characteristics are close to the peak values, and the values of the deformation curves appear rapidly after the peak stress is reached Tensile deformation until the sample is damaged. Splitting tensile loading and unloading cycle test found that most of the specimen tensile deformation is greater than the loading deformation, resulting in a negative residual deformation value, called the residual residual deformation. This phenomenon is inconsistent with the expected deformation behavior of continuous media, so far no similar reports. Whether the residual residual deformation is universal and its impact should be studied more.