3-D Finite Element Numerical Simulation Of Complex Resistivity And Global Optimization Inversion Of Spectral Parameters

Complex resistivity method,also known as spectrum induced polarization method,is an important branch of induced polarization method.This method has the characteristics of Multiple parameters provided and high construction efficiency.Compared with DC IP method,it can provide more abundant spectrum information.It has been widely used in mineral resources exploration,hydrological exploration,engineering geology,environmental treatment and so on.In order to promote the development of complex resistivity method,this paper carries out the research work of three-dimensional forward simulation of complex resistivity and spectral parameter inversion.Firstly,this paper summarizes the development status of complex resistivity method,briefly describes the basic principle of complex resistivity method,deduces the specific expression formula of Cole Cole model based on equivalent network model,and expounds the physical significance of each spectrum parameter.Without considering the electromagnetic induction coupling,the three-dimensional finite element numerical simulation method of complex resistivity of continuous electrical medium model is studied,mainly including the theoretical formula derivation of three-dimensional finite element numerical simulation of complex resistivity and the efficient solution of large sparse complex coefficient matrix equations.On this basis,a three-dimensional visual simulation software of complex resistivity is developed based on VC + +,which can quickly realize three-dimensional mesh generation and model construction through human-computer interaction.The operation of the software is convenient and flexible.Through the simulation and analysis of multiple geoelectric models,the correctness of the forward simulation algorithm and program is verified.In order to accurately obtain the spectrum parameter information of underground polarized body or rock and ore samples,this paper studies the hybrid inversion method of spectrum parameters based on genetic algorithm and Bauer direction method.In this method,firstly,the global optimization is carried out by genetic algorithm to obtain the approximate global optimal solution of the parameters of Cole Cole model,and then it is used as the initial solution of Bauer direction method.After many iterations,the spectrum parameters can be obtained accurately.The organic combination of genetic algorithm and Bauer direction method can not only improve the poor local search ability of genetic algorithm,but also suppress the defect that Bauer direction method is easy to fall into local extreme value.Numerical experiments show that the hybrid inversion method of spectral parameters combined with the two has the characteristics of fast convergence and accurate inversion results.