大颗粒柱状淡水冰无侧限剪切强度及其影响因素

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~5.00×10-2/s区间内、试验温度分别为-0.5℃、-2℃、-5℃和-10℃、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℃和-10℃条件下力学性质的各向异性更为明显,而在-0.5℃和-2℃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。

Study on the Unconfined Shear Strength of Large Columnar-Grained Freshwater Ice and Its Influential Factors

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 ℃ ,-2 ℃ ,-5 ℃ ,-10 ℃ and strain rates of 5 .0 × 10-5/s to 5 .0 × 10-2/s .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 ex‐perimental 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 me‐chanical properties was more obvious at the temperature of -5 ℃ and -10 ℃ ,and the shear strength under the two loading di‐rections had no visible distinction at the temperature of -0 .5 ℃ and -2 ℃ ;and (c) there was no significant correlation be‐tween the shear strength and gas bubble content when the gas bubble content was less than 8 .65% .