降水法凿井时井中残余水柱理论分析

Theory analysis of residual water column in course of shaft sinking with dewatering method

为了解决降水法凿井降水后期能否消除残余水柱的问题,对水跃产生根本原因及水跃理论进行了分析,认为:水跃值的影响因素主要有井壁结构、抽水量、地层渗透系数、降深、井径的函数等,水跃值与井抽水量、水井降深成正比,与井横截面积、地层渗透系数成反比;水跃值和降深成正比,随着降深趋向于全深,水跃值和降深之间的比值逐渐减小。并推导出潜水和承压含水层中抽水井的水跃公式和潜水含水层和承压含水层中稳定水位线的公式,为含水岩层疏排水数值模拟的参数修正以及降水井设计等方面提供科学依据。

In order to solve the problem of shaft sinking with precipitation eliminating the residual water column in later period,some conclusions were induced by analyzing the primary causes and the theory of hydraulic jump. The construction of the wall,pump output,stratum osmotic coefficient,drawdown,the function of well's diameter and other factors can influence the hydraulic jump value. The hydraulic jump value was proportional to the well water output and the well drawdown. It was inversely proportional to well's cross sectional area and the stratum osmotic coefficient; the hydraulic jump value was proportional to the drawdown. With the drawdown tending to whole depth,the specific value between hydraulic jump value and drawdown decreasing gradually. The hydraulic jump formula of pumping wells in diving and confined aquifer,the stable water line formula in diving and confined aquifer have been deduced. It will offer scientific basis to the parameter modification of simulation in water-bearing rocks drainage value,the design of precipitation well and other aspects.