冻融条件下岩石损伤劣化机制和力学特性研究

 通过循环冻融试验方法，研究岩石在冻融条件下的损伤劣化机制和相应的力学特性。研究对3种岩石(粉砂质泥岩、辉绿岩和白云质灰岩)在2种水化环境下(蒸馏水饱和，饱和并经1%硝酸溶液浸泡侵蚀)分别进行循环冻融试验研究(每循环冻融各4 h，共8 h)，并在不同循环次数下对试样进行饱和单轴压缩强度测试和质量变化测定。研究发现：岩石冻融损伤劣化模式受多种因素影响，不仅与岩石自身特性、冻融温度及循环次数有关，还与所处环境有关；在酸性条件下，岩石冻融强度损伤较纯水化条件下要剧烈得多。因此，纯水化环境下的冻融试验结果常常会给出较为危险的工程安全性评估。研究成果对寒区工程建设及工程安全运营具有重要的参考价值。

RESEARCH ON ROCK DEGRADATION AND DETERIORATION MECHANISMS AND MECHANICAL CHARACTERISTICS UNDER CYCLIC FREEZING-THAWING

The rock-degradation and deterioration mechanism and mechanical characteristics have been studied through freezing-thawing test method. Three types of rocks(silty mudstone，diabase and dolomitic limestone) and two water environments(saturation by distilled water and erosion in 1% nitrate after saturation by distilled water) have been considered in the freezing-thawing test，which includes four-hour freeze and four-hour thaw in each cycle，eight hours in total. Uniaxial compressive strength test and quality analysis due to different cycles have been performed at the same time. It is shown that the freezing-thawing degradation and deterioration models of the rocks are affected by many factors：not only the self-characteristics of rock，freezing-thawing temperature and number of cycle，but also external environments. The test results show that the strength degradation due to cyclic freezing-thawing is greater in acidic environment than that in distilled water environment；and the results of freezing-thawing tests in distilled water environment often give an underestimation in the actual projects. The research conclusions can provide valuable references to the construction and the safety operation of similar projects in cold regions.