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利用取自西藏玉龙铜矿的花岗岩试样进行变温度区间的冻融循环实验,分析饱水状态花岗岩在四种温度区间(-10℃~20℃、-20℃~20℃、-30℃~20℃、-40℃~20℃)冻融循环作用下的质量损失率、饱和吸水率、单轴抗压强度、弹性模量、峰值应变、泊松比、冻融系数。将实验结果应用于具体工程实例中,采用强度折减法计算冻融循环对花岗岩边坡稳定性的影响程度,分析边坡破坏模式,并提出相应的防护措施。研究结果表明:随着冻融温度下限的降低,花岗岩试样质量损失率、饱和吸水率、峰值应变略有增大,单轴抗压强度、弹性模量有所减小,温度下限降低至-30℃以下时,花岗岩抗冻性由较好变为较差。温度区间是岩石冻融过程中影响其物理力学性质的重要原因,该研究可为岩石冻融循环室内实验与寒区岩质边坡工程的有效结合提供参考。
The granite sample from Yulong copper deposit in Tibet was used to conduct freeze-thaw cycles in a variable temperature range, and the effect of saturated granite in four temperature ranges (-10 ℃ ~ 20 ℃, -20 ℃ ~ 20 ℃, -30 ℃ ~ 20 ℃, -40 ℃ ~ 20 ℃) mass loss rate, saturated water absorption, uniaxial compressive strength, elastic modulus, peak strain, Poisson’s ratio, freeze-thaw coefficient under the freeze-thaw cycles. The experimental results are applied to specific engineering examples. The degree of influence of freeze-thaw cycles on the stability of granite slope is calculated by strength reduction method. The failure mode of slope is analyzed and the corresponding protective measures are proposed. The results show that the mass loss rate, saturated water absorption and peak strain of granite increase slightly with the decrease of the freezing and thawing temperature lower limit, the uniaxial compressive strength and elastic modulus decrease, the lower limit of temperature decreases to - Below 30 ℃, the granite frost resistance changed from good to poor. The temperature interval is an important reason that affects the physical and mechanical properties of the rock in the process of freezing and thawing. This study can provide reference for the effective combination of laboratory experiments with rock freezing and thawing cycles and rock slope engineering in cold area.