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岩石在冻融循环作用下的损伤特性对评价寒区工程的稳定性和耐久性具有十分重要的意义.选取吉林集安某古建筑的花岗岩作为试样,在当地最低气温(-36.5 ℃)下反复冻融20次,冻融前后岩样的单轴压缩试验和电镜观测结果表明:经历多次冻融后岩石的单轴抗压强度下降5%~15%,弹性模量下降32%~46%,泊松比提高10%~19%,岩样中旧的裂隙明显变宽并产生新的裂隙.研究发现:低温冻融循环虽然对花岗岩的质量影响不明显,但对其强度、刚度及变形特性均有较大影响;岩石在低温冻融循环作用下损伤扩展的机理是裂隙增大、增多或发生扩展,从而使岩石强度、刚度降低,变形增大.图4,表2,参8.
The damage characteristics of rock under the freeze-thaw cycle is of great significance to evaluate the stability and durability of engineering in cold regions.Certain granite in Jilin Ji’an ancient building was selected as the sample, and at the local minimum temperature (-36.5 ℃) The freeze-thaw cycles were repeated 20 times. The uniaxial compression tests and SEM observations of rock samples before and after freezing and thawing showed that the rock uniaxial compressive strength decreased by 5% -15% and the elastic modulus decreased by 32% -46 after repeated freeze-thaw cycles % And Poisson’s ratio increased by 10% -19%, the old fractures in the rock samples obviously broadened and new fractures were generated.Research shows that although the low-temperature freeze-thaw cycles have no obvious effect on the granite quality, its strength, stiffness and Deformation and deformation of the rock have a greater impact; rock under low temperature freeze-thaw cycle mechanism of damage is the crack growth, increase or expansion, so that the rock strength, stiffness decreases, the deformation increases .Figure 4, Table 2, reference 8 .