复杂干扰环境下抽水试验参数分析

Analysis on parameters of pumping test under complicateddisturbed-environment

针对复杂干扰环境下,为了准确获取场区水文地质参数,开展了2个降深的抽水试验,第一个降深抽水试验流量为173 m^3/h,抽水75h 30 min(4530 min),停抽后立即进行恢复试验,共恢复88 h(5280 min),整个试验过程共计163 h 30 min(9810 min);第二个降深抽水试验流量为84 m^3/h,抽水99 h(5940 min),停抽后立即进行恢复试验,共恢复163 h 30 min(9810 min),整个试验过程共计262 h 30 min(15750 min)。参数求解时,首先通过对抽水试验数据应用多种解析法求参数,计算出场区潜水含水层渗透系数为21~24 m/d,然后采用数值法反演求参数,求得渗透系数为24 m/d,反演结果与多种解析法计算的结果相互对比验证,计算结果接近,结合场区水文地质条件及工程经验,综合分析确定场区潜水含水层的水文地质参数为23 m/d,计算结果合理可信,并已应用于工程设计,同时为在复杂环境下抽水试验求参提供了参考与借鉴。

In order to accurately obtain the on-site hydrogeological parameters under complicated disturbed-environment,two drawdown pumping tests are carried out.The discharge of the first one is 173 m^3/h with the water pumping period of 75 h 30 min(4530 min)and the recovery test is carried out immediately after pumping stop with the recovery period of 88 h(5280 min),thus the whole test process is 163 h 30 min(9810 min).The discharge of the secondone is 84 m^3/h with the water pumping period of 99 h(5940 min)and the recovery test is carried out immediately after pumping stop with the recovery period of 163 h 30 min(9810 min),thus the whole test process is 262 h 30 min(15750 min).When solving the parameters,various analytical methods are adopted to solve the parameters for the pumping test data,and then the permeability coefficient of the on-site phreatic aquifer is calculatedto be 21~24 m/d,while the parameters are inversed with numerical method and then the permeability coefficient of 24 m/d is obtained.The inversion result is comparatively verified with those from various analytical methods,for which all the calculation results are close to each other.Combined with the on-site hydrogeological conditions and the relevant engineering experiences,the hydrogeological parameter of 23 m/d is determined for the on-site phreatic aquifer through the comprehensive analysis concerned.The calculation result is reasonable and credible,which is already applied to the relevant engineering design and simultaneously provides reference for parameter solving for the pumping test made under similar complicate environment.