三向受力条件下冻结岩石力学特性试验研究

 随着寒区或特殊施工环境条件下基础设施建设的需要，越来越有必要对冻结岩石力学问题进行深入的研究。以陕西彬长矿区胡家河煤矿冻结立井为背景，从现场采集的煤岩和砂岩为代表，进行常温(+20 ℃)和不同冻结温度(－5 ℃，－10 ℃，－20 ℃)条件下的岩石在不同围压下的三轴压缩试验。分别探讨了围压对于冻结岩石三轴强度特性的影响和冻结温度对于冻结岩石三轴强度特性的影响规律，分析煤岩及砂岩在相同围压不同温度条件下及相同温度不同围压条件下的强度特性，并对2种岩样冻结温度的同一性和差异性进行比较研究。煤岩和砂岩在冻结的效应方面有着明显的差异性，主要原因是其岩石内部结构性的差异。富水砂岩冻结后对温度的敏感程度要高于煤岩。强度随温度降低而增大的主要原因是温度降低时，岩石冻结时的矿物收缩和冰本身的强度及冻胀力使得富水冻结岩石的峰值强度得到提高。为低温条件下岩石力学特性和煤矿冻结立井设计施工提供参考。

EXPERIMENTAL STUDY OF ROCK MECHANICAL PROPERTIES UNDER TRIAXIAL COMPRESSIVE AND FROZEN CONDITIONS

With the demands of fundamental construction in cold regions or special construction environment,it is more necessary to research the problems occurring in frozen rock mechanics. Taking the frozen shaft project of Hujia River coal mine in Shaanxi Bingchang coal mine area as the project background,sandstone and coal samples collected from the field,respectively,are tested under the triaxial compression at different confining pressures at the room temperature 20 ℃ and different freezing temperatures of -5 ℃,-10 ℃ and -20 ℃. Based on the experimental results,the influential law of confining pressure and freezing temperature on the triaxial strength properties of frozen rock is explored;and the strength properties of sandstone and coal samples under the same confining pressure at different temperatures and different confining pressures at different freezing temperatures are analyzed;and the identity and discrepancy of two rock samples on freezing temperature are comparatively studied. Due to the internal structural difference,the frozen effects of sandstone and coal exist obvious difference. Frozen water-rich sandstone is more sensitive to temperature than that of coal. Strength of the water-rich rocks increases with the decrease of temperature which is mainly due to the peak intensity of rocks greatly improved by mineral contraction and ice strength and frost heave force with temperature decreasing. The result provides some references for studying rock mechanics under cold environment and the construction and design for freezing shafts of coal mines.