水工建筑物的基坑,在大多数情况下,均开挖到低于地下水位的岩層內吮T^基坑能正常工作,必須进行井羣人工排水以降低地下水位。但在不同的地質技术条件(参閱附录一)下,井羣工作的类型可以分成下面三类:1.自流井羣(圖1);2.潛水井羣(圖2);3.潛水-自流井羣(圖3)。对不同类型的井羣,应有不同的計算公式和方法,分析了地下水流向自流井羣,潛水井羣以及潛水-自流井羣运动的特征后, In most cases, the foundation pit of a hydraulic structure can work normally within a rock formation below the groundwater level, and the artificial pit drainage must be carried out to reduce the water table. However, under different geotechnical conditions (see Appendix I), the types of well group work can be divided into the following three categories: 1. Artesian well group (Fig. 1); 2. Submarine well group (Fig. 2); 3. Submersion- Group (Figure 3). For different types of well groups, there should be different formulas and methods. After analyzing the characteristics of groundwater flowing to artesian well groups, submersible well groups and submarine-artesian wells,