用瞬时模拟抽水试验确定水文地质参数

DETERMINING HYDROGEOLOGICAL COEFFICIENTS BY THE METHOD OF TRANSIENT ANALOGOUSPUMPING TEST

最近发展起来的瞬时抽水试验由于抽水时间短,解决了长时抽水试验中一些经常碰到的问题。但它仍然需要一个观测孔和一套笨重的抽水设备,因此它限制了瞬时抽水试验的广泛成用。为了克服瞬时抽水试验的一些缺点扩大其应用范围,我们在原来工作基础上,提出了确定水文地质参数的新方法——瞬时模拟抽水试验法。

The method of transient analogous pumping test based upon the transient pumping test is a new method for determining hydrogeolo-gical coefficients.Without pumping equipments and of servation wells, the process of the method is instantaneously to lift a solid column(v) that soa- ked in the well previously, and to observe the change of water levelin the same well.The similarity between the two processes, lifting a column in aninstant and doing a trasient pumping test, is the basic principle of the method presented in this paper.The equation of the method of transient pumping test is as follows:The new method of hydrogeological coefficient calculation, which is named'match point method,' is resulted from the solution of equation (1) . That is, substituting ro for r by moving calculative pointto the wall of the well and making e -r2o/4at → 1 because r02<<4at.There fore.Converting it to common logarithms. ThenWhere, = constant.Two match points which coordinates can be checked from S-T and-1/θ-θcurves will be found after matching two lines of lgs-lgt and lg1/θ-lgθ.And thepoints must suit the equations( 2 )and( 3 )well.Thus,the coefficientsμ,a,T are obtained by match points.