阶梯状抽水试验水文地质参数确定

Approach to Determine the Aquifer Parameters for Step-Drawdown Test

针对传统阶梯状抽水试验参数计算过程中,通常只选择抽水阶段的部分试验数据等问题,应用Theis公式及叠加原理,利用抽水试验所有降深数据(抽水和水位恢复阶段全部资料)求解水文地质参数,利用承压含水层抽水试验数据计算得出导水系数、储水系数,利用潜水含水层抽水试验数据计算得出渗透系数和给水度,此外在低效率抽水井中利用抽水试验数据计算得出井损系数和井流量指数。计算过程中,利用Excel计算并绘制计算水位降深和观测水位降深的拟合曲线,计算过程简单快捷。整个抽水试验过程中,不必再分别提出抽水、水位恢复期的计算公式,可以避免人为选择单个水位降深数据对参数求解带来的影响。

Traditional analysis for step- drawdown tests always uses selected data during the pumping period. In this paper,a new approach which was based on the Theis formula and the principle of superposition and all the data obtained from the tests were used to determine the aquifer parameters. The transmissivity and storativity could be obtained in confined aquifers and specific yield and hydraulic conductivity could be obtained from the unconfined aquifers. In addition,the coefficient of well lose and the exponent of the discharge of the pumping well could be calculated based on the pumping tests data. It was simple and quick as Excel was used to calculate the observed drawdown and the calculated drawdown and made the fitted curve of them. There was one formula in the whole pumping test,including pumping period and water recovery period,the influence of choosing the individual pumping data by hydrologist was avoided.