利用Wenner四极法确定三层土壤模型

Determination of a three-layer earth model from Wenner four-probe test data

确定大地模型和土壤参数是变电站接地网模拟计算和计算机辅助设计的首要工作 ,为了使模型能够较好地反映实际大地土壤特性 ,应该利用三层模型替代以往的两层模型。基于求解场域结构和媒质参数的逆问题理论 ,论文提出了一种利用 Wenner四极法测量数据来确定三层大地模型的有效方法。该方法将三层大地模型的三个电阻率和两个厚度参数的确定转化为一个五变量的线性优化问题 ,进而变为对一个非线性方程组的优化求解 ,由于对所要求解的方程组采用了广义逆算法 ,并且基于视在电阻率分布特性确定迭代过程的初始值 ,使迭代收敛速度大为提高。用该方法编制的软件可以有效。

The determination of earth structure and solid parameters is essential in the simulation and design of substation grounding electrodes or grounding grids. When the earth structure is complicated, the three layer earth model is used instead of two layer model. An efficient method for determining three layer earth models and parameters from Wenner's four probe test data is developed based on the solution of the electric field inverse problem, using a set of voltages measured on the earth surface due to the current injected into the earth. The speed of the iterative convergence is increased by employing the generalized inverse algorithm for solving the nonlinear system of equations and by using a suitable method for determining initial values for the iterative process. The analysis is efficient and accurate.