Study on Application of Magnetotelluric Constrained Inversion in Tunnel Exploration

Research purposes: Base on the study on the principle of OCCAM inversion method,the objective function of the OCCAM was modified,the constrained inversion item was added,the concept of constrained inversion of electrical parameter was proposed and the inversion of electrical parameter module was developed to improve the resolving ability of the magnetotelluric method for the exploration of large railway tunnel. Research conclusions:From the comparison of the model's conventional onstrained inversion result with the electrical parameter result,it could be seen that the imaging effect of the constrained inversion with prior information was better than the conventional inversion.The method was used for the data processing,and the comparison of the results before and after constrained inversion for the Fangdoushan Tunnel showed that the constrained inversion results of the geological structure such as the fold,fault and karst more tallied with the real situation.