单轴压力下岩石破裂的初步研究

用几种不同加载方式对岩石样品进行了单轴压力实验。以恒定应变率(约为10^-5)对样品加载时,岩石的破裂过程大致可分成四个阶段:孔隙压缩阶段、弹性变形阶段、体积膨胀阶段和临震阶级。后二个阶段显著的特点是岩石开始表现出非弹性的体积应变并在主破裂前急剧增大,它与微破裂累积总数二者存在着同步的变化。在重复加载时,发现岩石的微破裂过程具有不可逆的性质,这种现象似乎可以用来说明同一地区短期内发生的两次地震的地震序列的不同,指出运用历史地震资料时应注意该地区应力变化的历史情况。

A PRELIMINARY STUDY ON THE FRACTURE OF ROCKS UNDER UNIAXIAL COMPRESSION

The uniaxial compression tests under different ways of loading were performed on a variety of rock samples. When loading with constant strain rate （about 10^-5）, the fracture process of the rocks generally may be divided into four stages: com-pression of pores, elastic deformation, volume dilatation and the period just preced-ing an imminent rupture. The last two stages are characterized by the initiation of a non-elastic volume strain which increases sharply just before the main rupture. This sort of volume strain varies in coincidence with the accumulated number of microfractures. As the loading is repeated, the process of microfracturing appears irreversible. This might be used to explain the difference between the sequences of two earthquakes when they occurred within a short interval of time in the same region one after the other. It is pointed out that due attention must be paid to the history of stress variation in an area when historical records of earthquakes are to be studied.