基于裂隙网络模型的地下水数值模拟误差分析

Error analysis of groundwater numerical simulation based on fissure network model

以二维裂隙网格中地下水流动数值模拟问题为例,分析了其模型误差、观测误差和计算误差。首先给出了该二维地下水问题的解析解,然后详细讨论了数值模型的解法及其误差。计算结果表明,线素法较有限元法误差更小,同时求解大型线性方程组时,应采用置大数法。最后以裂隙宽测量为例,讨论了观测误差对水头计算结果的影响。分析认为,前期准确可靠的地质勘察,是后期提高数值模型模拟精度的前提条件和重要保证。

Aiming at the problem of underground flow in 2D fissure network,the model error,measuring error and computation error are analyzed. The analytical solution of the 2D underground flow issue was given,and the numerical solution method and its error are further discussed in detail. The computation results show that the error of line element method is smaller than that of FEM,and the method of laying large coefficient is recommended in the solution of large linear equations. The influence of measuring error on the computation results is discussed by taking the fissure width measurement as example. It is pointed out that the accurate geological exploration in early stage is an important guarantee and premise for increasing the accuracy of later numerical simulation.