为探索三江源区岩体冻融风化特征及规律,明确主控因子对岩体冻融损伤裂化过程的影响,在野外科学考察基础上,结合航拍影像,通过开展岩石切片观察和岩石物理指标测试,总结了源区岩体冻融风化特征,归纳了岩体冻融破坏过程,分析了主控因子对岩体冻融损伤劣化过程的影响,得出以下结论①岩体冻融风化强度具有垂直分带性、纬度坡降性和水平方向性3个基本特征;②岩体呈明显的“立体状”冻融风化特点,且不同岩性岩体冻融风化所产生的碎屑坡形态和碎屑形态差异明显;③岩性对岩体抗冻融风化性起着至关重要的作用,孔隙和孔隙水是影响岩体冻融风化过程的2个基本条件,而冻融循环次数则对岩体冻融损伤劣化过程起着决定性作用。

To explore the characteristics and regularity of freeze-thaw weathering of rock mass in the headwaters region of three rivers (Yangtze River, Yellow River, and Lantsang River), we conducted rock slice observation and physical property test. On this basis and in association with scientific field investigation and aerial images, we summarized the characteristics of freeze-thaw weathering, concluded the process of freeze-thaw damage of rock mass, and analyzed the influences of key factors on the freeze-thaw damage process. Here we present the conclusions as follows: 1)the intensity of freeze-thaw weathering declines with the increase or decrease of latitude, weathered rock exposure is more severe with the increase of altitude (with altitude 5000m as an obvious dividing line), rock mass weathering in the north slope (dark side) is weaker than that in the south side (sunny side); 2) the intensity of freeze-thaw weathering of exposed rock mass is different, and the slope form and clastics induced by freeze-thaw weathering differ greatly as for rock mass of different lithological characters; 3)the lithology of rock mass plays an important role in the freeze-thaw weathering. Porosity and pore water are two basic conditions affecting the freeze-thaw weathering process, and the number of freeze-thaw cycles plays a decisive role in the freeze-thaw damage process.