Two-stage algorithm for inverting structure parameters of the horizontal multilayer soil

The multilayer soil structure model is the fundament to design grounding systems. A fast algorithm is presented to invert the structure parameters of the horizontal multilayer soil. The procedure is divided into two independent stages. First, Fredholm equation of the first kind with respect to the apparent resistivity is solved by using the technology of decay spectrum, which can reduce the computation time greatly. Second, the structure parameter of soil is determined by the generalized Newton-Kantorovich method, which is more robust and less noise sensitive because of using the generalized inverse algorithm to solve the nonlinear equation system. The numerical results show the validities and main features of the proposed approach. The numerical results by using the proposed method are in a good agreement with ones from geophysical exploration.