典型小流域裂隙岩体渗流补给特性试验研究

Field experiment on discharge of rain seepage from fissured rock in a catchment

采用野外试验,在分析典型小流域坡地地质结构特征的基础上,针对下垫面的非均质性和空间变异性,通过测定坡地岩土的水分变化和流域出口裂隙岩体渗流对降雨入渗的响应,对天然降雨条件下的小流域水量转化特性进行了分析。得到如下结论:裂隙岩体渗流对暴雨过程具有明显响应;岩土二元结构下垫面具有较强的储水和透水功能,为降雨入渗过程中土壤层与裂隙岩体层之间形成暂时饱和区创造了地质条件,这为坡地渗流的集蓄技术提供了理论依据;水分在风化裂隙岩体中的运动存在优先流现象,这说明考虑下垫面的非均质性和空间变异性将有助于正确认识水分在风化裂隙岩体中运动的真实性,也说明等效连续介质模型在风化裂隙岩体中是不合理的。

Field measurements were carried out to investigate the discharge of rain seepage from fissured rocks characterized by a stony layer of weathered gneiss beneath a shallow soil layer. Geohydrological characteristics of different layers were measured. The movement of soil water along several soil profiles and the response of seepage flow at the outlet of a small catchment to rainfall during a rainfall event were monitored and analyzed. It is concluded that： 1 . the weathered rocks has strong water storage and permeability and can become an instantaneous saturated zone with the soil layer at the top and the gneiss layer at the bottom; 2. preferential flow exists in the inhomogeneous and spatially variable soil profile, therefore, the equivalent continuum model is not suitable for analyzing the movement of water in the catchment.