黄土高原土石山区碎石分布特征及其导水性质分析

天水凤凰山中等风化变质岩碎块含量随土层增加含量增大;各层土体中粒级为2~5 mm碎石含量在各坡位变异小,坡中、坡下处粒径大于25 mm碎石含量相对高;铜川崾崄梁坡上土体的风化沉积岩碎石含量有随着土层加深有增大的趋势,其他坡位该趋势不明显,含量最高的为10~30 mm碎石;泾阳张家山卵石含量在坡位和土层上分布差异较小,粒径10~30 mm碎石含量最高。中等风化的块状碎石构成的土石介质的饱和导水率(ks)与土石比(土壤和碎石的质量比)关系呈对数关系,而片块状沉积岩碎屑构成的土石介质的ks与土石比关系呈正比线性关系;而椭圆卵石构成的碎石构成的土石介质ks与土石比无明显关系。

Rock Fragments Distribution and Hydraulic Conductivity Analysis of Soil-stone Mixture in the Mountain Area of Loess Plateau

Content of medium weathering metamorphic rock fragments increased with soil depth,and the content of smaller rock fragments(from 2 to 5 mm) had few variation in whole slope while the content of larger rock fragments(>25 mm) was greater in mid-slope and bottom-slope than top-slope in the Fenghuang Mountain;the content of strength weathering sedimentary rock fragments in the upslope of Yaoxian Mountain increased with soil depth either,and the content of rock fragments from 10 to 30 mm was greatest;the content of gravel in Zhangjiashan varied lightly with various slope location,and the maximum content of rock fragments was also from 10 to 30 mm.The relation between hydraulic conductivity of soil-metamorphic rock fragment mixtures and soil-stone ratio(the ratios of soil mass content and rock fragments mass content)could be described by logarithm function,and the relation between hydraulic conductivity of soil-sedimentary rock fragment mixtures and soil-stone ratio could be described by direct liner function,while the relation between the relation between soil-pebble mixture and soil-stone ratio was not clear.