玉龙雪山西麓冰碛(水)砾岩的工程地质特性研究

Research on the Engineering Geological Properties of Moraine/Outwash Rocks on the West Side of the Yulong Mountains

作为滇西北、川西和西藏地区最重要的第四纪堆积物类型之一,冰川堆积物的工程性质及其相关的地质灾害和工程问题研究日益受到工程界的关注。通过对上述地区大量冰碛物和冰水沉积物的现场调查发现,冰碛物和冰水沉积物是一类成分、结构和性质都十分复杂的第四纪堆积物,其工程性质主要与母岩成分和充填胶结物的矿物成分密切相关。发育在石灰岩地区的冰碛物和冰水沉积物因钙质(方解石)的次生胶结,而成为单轴抗压强度达10.94-14.22 MPa的岩石,作者称其为“冰碛(水)砾岩”。结合滇藏铁路滇西北段线路比选和优化工作,对云南玉龙雪山西麓第四纪冰川堆积物的类型和分布特征进行了详细的野外调查;在室内物理力学试验的基础上,着重研究了冰碛(水)砾岩的胶结物成分与胶结作用、水稳性、力学性质、声波速度等方面的特性,这不仅可以丰富现代岩石力学的研究内容,而且对本区铁路工程建设和水力资源的开发具有重要的实际价值。

As one type of important Quaternary deposits distributed in Northwest Yunnan, West Sichuan and Tibet of China, the study of the engineering properties of glacial deposits and their related geo-hazard, as well as engineering problems, have attracted the attention of many engineers. Based on investigation of the moraine and outwash deposits in above regions, the authors find that they are very complicated Quaternary deposits with special composition, structure and properties. Their engineering properties are mainly related with the composition of the gravel and the filled material, e.g. the moraine and outwash deposits distributed in limestone areas can turn into rocks, named moraine rock or outwash rock, caused by calcite cementation, which has a uniaxial strength from 10. 94 MPa to 14. 22 MPa. This paper has presented the types and distribution characteristic of the Quaternary glacial deposits on the west side of the Yulong Mountains, which was an important task for the selection and optimization of the Yunnan-Tibet railway line in Northwest Yunnan. Based on lab test of physics and mechanics, the results of engineering properties of moraine/outwash rocks, including the cement composition and their cementation, stability in water, mechanical property, and sound spreading velocity, etc. , have been reported, which can not only enrich the research contents of rock mechanics, but also have important practical value for railway construction and water power development in mountain regions.