滨海承压含水层地下水的等效排泄边界——以北海禾塘村水源地为例

THE EQUIVALENT DRAINAGE BOUNDARY AND ITS DETERMINATION OF CONFINED AQUIFER IN THE COASTAL REGION:FOR HETANG AREA OF BEIHAL CITY

用钻探方法直接查明滨海平原区承压水与海水的水力联系耗资巨大。本文把滨海承压含层的海底边界划分为线状集中排泄和面状越流排泄两种基本类型,其它为过渡类型。提出“等效排泄边界”概念,把其它排泄边界类型转变为线状集中排泄边界类型,而使其渗透阻力或水头损失是相同的。文中利用地下水的潮汐效应编制三张关键性的图件(地下水水头波动中值等高线图,地下水水头波动等幅线图和地下水波动滞后等时线图)来确定等效排泄边界的位置。由此通过准三维有限元法预测了北海市禾塘村水源地在不发生海水入侵条件下的最大开采量。

The boundaries of canfined aquifer which extendunder the sea are divided into two types, in thispaper i. e. the linear concentration drainage type andthe surface leakage drainage type. Besides there isthe mixed type. Any boundary other than thar of theliear concentration drainage type may be transformedinto this type with the same seepage resistance orhead less, which is called equivalent drainage bou-ndary. The three maps of critical factors are alsopresented in the paper by using the tidal effect ofgroundwater. The position of the equivalent drainage boundarythen can be decided according to the three maps andfinally the maximum quantity of groundwater explo-ita?on of the Hetang area in Beihai city is predictedby a quasi-three dimensional numerical model--thefinite element method.