含水层底部单孔非完整疏放水井渗流特征砂槽试验

Title

Sand tank test on seepage characteristics of a single partially penetrating de⁃watering well from the bottom of an overlying aquifer
作者

王文学郝清扬薛景元姜彤董金玉
Author

WANG Wenxue;HAO Qingyang;XUE Jingyuan;JIANG Tong;DONG Jinyu
单位

华北水利水电大学河南省岩土力学与结构工程重点实验室
Organization

Henan Province Key Laboratory of Rock and Soil Mechanics and Structural Engineering,North China University of Water Resources and Electric Power
摘要

为研究含水层底部疏放水井渗流特征,设计研发了一种60°扇形体渗流砂槽系统,以潜水含水层底部疏放水为例,开展了不同井长单井非完整井疏放水渗流砂槽试验,研究结果表明:疏放水引起浸润线的下降,并在其上方形成饱和毛细水带负压区;疏放水过程中含水层底部非完整井上部可划分为上层毛细水带、支持毛细水带、饱和毛细水带及自由水饱和带,饱和毛细水带可有效阻止上部空气进入井内;非完整井井片内部压力P 存在4 种水压分布形态,即P = 0、P>0、P<0 以及Pup <0 且Pdown >0,根据井内压力及井片上部自由水饱和带、饱和毛细带的分布,含水层底部非完整井疏放水似稳定流态水压分布可概化7 种模型;非满管段的形成导致其上部自由水压力不能连续传递,其分布不再是满管时的由下至上递减规律,当井片上方存在浸润线时,压力水头分布由下至上呈先增加后减小的规律;当井片上方存在自由水饱和带或较大范围的饱和毛细水带时,渗流量随井内压力减小而增加,当自由水饱和带消失且饱和毛细水带垂直分布较小时,井内压力的减小对渗流的增加效应不明显;非完整井井长的增加可有效增加渗流量,但当井长大于临界值后,渗流量不再随着井长的增加而变化;疏放水过程中,疏放水量由静态补给与动态补给构成且静态补给以一阶指数函数减少、动态补给以一阶指数函数增加。
Abstract

In order to study the seepage characteristics of dewatering from an aquifer bottom,a sand tank systemwas designed with the cross section being a sector of 60°,and the dewatering test from an unconfined aquifer bottom u⁃sing partially penetrating dewatering wells with different well lengths was conducted. The results show that the phreaticline falls off with dewatering process,and a saturated capillary zone with negative pressure forms above it. The up⁃per capillary zone,supporting capillary zone,saturated capillary zone and free water saturation zone can be formed a⁃bove the dewatering well in aquifer,and the saturated capillary zone can effectively prevent the upper air from ente⁃ring the well. The well inner pressure P includes four kinds of circumstances,which are P =0,P>0,P
关键词

渗流特征底部疏放水非完整疏放水井砂槽试验
KeyWords

seepage characteristics;dewatering from bottom;partially penetrating dewatering well;sand tank test
图表
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