厚层非饱和黄土中优势流和活塞流的讨论  

DISCUSSION ON PREFERENTIAL FLOW AND PISTON FLOW IN THICK LOESS VADOSE ZONE

作　　者：李同录[1,2] 汪颖 胡向阳[3] 李萍[1,2] 王宇 LI Tonglu;WANG Ying;HU Xiangyang;LI Ping;WANG Yu(School of Geological Engineering and Geomatics,Chang an University,Xi an 710054,China;Observation and Research Station of Water Cycle and Geological Environment for the Chinese Loess Plateau,Zhengning 745300,China;Power China Northwest Engineering Corporation Limited,Xi an 710065,China)

机构地区：[1]长安大学地质工程与测绘学院,西安710054 [2]黄土高原水循环与地质环境教育部野外科学观测研究站,正宁745300 [3]中国电建集团西北勘测设计研究院有限公司,西安710065

出　　处：《工程地质学报》2022年第6期1842-1848,共7页Journal of Engineering Geology

基　　金：国家重点研发计划项目(资助号:2021YFE0111900);国家自然科学基金项目(资助号:42041006)。

摘　　要：厚层黄土中包气带水的运动方式一直存在争议。一种认为是活塞流,另一种认为是优势流,也有人认为两者并存。本文通过现场观测和两个模型试验,揭示活塞流是包气带中水分的特有的运移方式;基于非饱和土的土水特征,进一步证明优势流仅存在于饱和土中。自然界的黄土多处于非饱和状态,因此活塞流是黄土包气带中水的主要运移方式,而优势流是暂态和局部的,仅出现在降雨时期的浅层饱和区,或者低洼的汇水区。黄土中的垂直节理、卸荷裂隙、动物洞穴和植物根孔等优势通道是地表汇流的排水通道,而不是地下水的补给通道。The mode of water migration in thick loess vadose zone has always been argued on preferential flow and piston flow.In this paper,the authors conducted in-situ observations and two model tests to demonstrate that piston flow is the unique way of water migration in vadose zone in thick loess.Based on flow behavior of unsaturated soil,it is also verified that preferential flow can only exist in saturated soils.Loess in natural condition mainly exists as unsaturated state,so piston flow is the dominant flow mode in loess.Preferential flow just occurs in shallow saturated zone locally and in the raining periods temporally.In addition,preferential paths in loess,such as vertical joints,load release cracks,animal caves and root pores are the channels for surface water discharge rather than those for groundwater recharge.

关 键 词：黄土 包气带 地下水 优势流 活塞流 

分 类 号：P64[天文地球—地质矿产勘探]