开采量不确定条件下数值模拟结果的可靠性分析

地下水数值模拟过程中,人工开采量大都被当作确定项处理。但实际情况是开采量往往缺乏准确的统计数据,尤其是农业灌溉开采量,在计算中具有更大的不确定性。传统的处理方法是将这些人工开采量概化为抽水量确定的开采井,显然不能反映实际情况。采用概率论及数理统计的方法,分析了概化后开采量的不确定性,得出开采量服从正态分布。以此为基础,运用蒙特卡罗方法,对开采量不确定条件下数值模拟的结果进行可靠性分析。结果表明:传统处理方法不能反映开采量不确定条件下数值模拟结果可靠性的变化情况,而采用随机模拟的方法,可以计算出不同的给定允许降深条件下,模拟结果的可靠性。

Reliability Analysis of Numerical Simulation Results under the Condition of Groundwater Withdrawal Uncertainty

In the process of groundwater numerical simulation,groundwater withdrawal is always treated as certain sink item for long time.However,due to lack of accurate statistic data,there exists uncertainty in determining groundwater withdrawal,especially groundwater withdrawal for agricultural irrigation.The traditional method is to simplify the irrigation as several pumping wells with certain pumping rate.Obviously,it can not reflect the real uncertainty of pumping rate.Monte Carlo method is used to structure the stochastic numerical simulation model to fully consider this uncertainty.Based on the probability theory and mathematical statistics,it is concluded that the pumping rate of the hypothe-tical wells follows normal distribution.The results demonstrate that the traditional method which ignores the effects of uncertainties can not provide the information of reliability of simulation results.But the stochastic simulation can give necessary results for different reliability demands.