小江流域风化物的水理特征差异规律的实验研究

Experimental Research on Hydrological Characteristics of Weathered Materials of Rocks in Xiaojiang Basin

水理性质是风化土体对降雨过程中入渗水的响应性质,对泥石流起动有着重要影响。以中国泥石流最为发育的小江流域为研究区,采集流域上、中、下游5个流域,9种类型岩石的19个风化物样品及5个典型泥石流沟的泥石流堆积样品,通过液塑限及渗透实验获取水理特征参数。选择塑限、塑性指数及渗透系数等3个指标构建指标体系,系统分析了不同岩性各指标的差异规律。结果表明,对于各项指标,各岩性风化物均差异显著,且随指标不同,其水理特征差异规律显著不同。5个典型流域泥石流堆积物在各项水理特征指标上均具有较好的一致性。塑限、塑性指数及渗透系数所构建的指标体系能较为客观、系统、合理地反映各风化产物的水理性质,可为泥石流对岩性的敏感性研究提供帮助。

As the response characteristics to rainfall infiltration into weathered materials of rocks, hydrological properties have important influences on the initiation of debris flow. In this paper, Xiaojiang basin was taken as the study area to investigate the difference of hydrological properties of weathered materials from different kinds of rocks. 19 samples of weathered materials from 9 kinds of rocks with different elevations and 5 samples of debris flow deposition were collected in 5 debris flow valleys in the upper, middle, and lower reaches of Xiaojiang basin. Liquid and plastic limits and permeation experiments were taken to obtain the hydrological characteristics of each sample. Based on the construction of the index system with three indicators of hydrological characteristics, the variation of hydrological characteristics for each indicator were systematically analyzed. Results indicate that for each indicator, there are significant differences in weathered materials. The variation of its hydrological characteristics is significant for different indicators. In addition, for each indicator, there is the good consistency in hydrological characteristics of debris flow deposits in the 5 typical debris flow valleys of Xiaojiang basin. The index system, can reflect the hydrological properties of weathered materials, systematically, objectively, and reasonably. It may be helpful for the susceptibility analysis of debris flow to rocks based on hydrological characteristics of their weathering products.