黄土粒度的分布特征及其工程地质意义初探

黄土的粒度组成和分布既能够反映其沉积环境,又在很大程度上决定了黄土的物理力学及水理性质。粒度分析表明黄土的粒度频率分布曲线包含多峰分布和单峰分布两种形式。对比研究发现:粒度具多峰分布的黄土其粘粒含量相对较高,微结构一般为镶嵌微孔半胶结结构或絮凝状胶结结构,比表面积大,平均孔径小,微孔隙和小孔隙含量高,一般超过孔隙总量的60%,其工程地质性质明显优于具单峰分布的黄土,且多峰分布特征愈明显即细粒部分的次峰愈高,其工程地质性质愈稳定,渗透系数的各向异性愈低。

Grain size distribution of loess and its implications for engineering geology

Grain size component and distribution of loess not only reflect sedimentary environment but also decide physical-mechanical and hydraulic properties.Grain size distribution curves of loess could be divided into two types:unimodal distribution and multi-peaking one.Comparing with the unimodal loess,the multi-peaking loess had following characteristics:the higher clay component,more tightly microstructure,bigger specific surface,smaller average aperture,and generally the contents of micro- and small pores exceeding 60%.Furthermore,the engineering geology character of multi-peaking loess was more stable than that of the unimodal loess.