针对大颗粒柱状冰无侧限剪切强度同加载方向、加载应变速率和冰样温度有关，在加载应变速率5.00?10-5 s-1~5.00?10-2 s-1区间内、试验温度分别为-0.5°C、-2°C、-5°C和-10°C、进行两个加载方向分别为垂直加载（加载力平行于晶体生长方向）和水平加载（加载力垂直于晶体生长方向）的无侧限剪切试验。结果发现，在既定试验条件下，剪切强度随着温度和应变速率的减小有增大趋势；比较两个加载方向剪切强度可知，在-5°C和-10°C条件下力学性质的各向异性更为明显，而在-0.5°C和-2°C时两个加载方向剪切强度相差不大；另外在气泡含量小于8.65%情况下，冰内气泡含量对大颗粒柱状冰剪切强度影响不大。

Considering that the unconfined shear strength of large columnar-grained freshwater ice is associated with loading directions, loading strain rate and temperature, we conducted the unconfined shear test at the temperature of -0.5°C, -2°C, -5°C, -10°C and strain rates of 5.0 ? 10–5 s–1 to 5.0×10–2 s–1. Two loading modes were used in our test: vertical loading (the loading force was parallel to the crystal growth direction) and horizontal loading (the loading force was perpendicular to the crystal growth direction). The experimental results showed that (a) the shear strength increased with the decrease of temperature and strain rate under the given experimental conditions; (b) comparison of shear strength under the two loading directions showed that the anisotropy of mechanical properties was more obvious at the temperature of -5°C and -10°C, and the shear strength under the two loading directions had no visible distinction at the temperature of -0.5°C and -2°C; and (c) there was no significant correlation between the shear strength and gas bubble content when the gas bubble content was less than 8.65%.

国家自然科学基金项目(51579028, 41402203, 41376186)