Study On Geophysical Joint Inversion Methods For Hidden Dam Safety Hazards

Embankment hazards have always been an important topic of national security and people's security.Embankments exposed to nature have always been affected by the natural environment,biological activities,and human activities.Through census of reservoirs,it was found that many reservoirs have different degrees Hidden dangers not only affect the economic and social benefits that the dam can bring,but also threaten the lives and property of the people in the area around the dam.These hidden dangers are not only common in small reservoirs,but also exist in different places in many rivers and rivers.This paper introduces the types and hazards of dam safety hazards,describes the development history of geophysical nondestructive testing and an overview of geophysical inversion methods.It leads to the joint inversion of geophysical parameters from the same physical property parameters to different physical property parameters.Four basic links,namely model parameterization linearization,normalization and linearization,construction of objective function,selection of inversion algorithm;because the effect of inversion is often not completely consistent with the physical interface,the solution is often in these four directions.Intensive efforts;use the structural differences of the model to derive and derive the theoretical formula for the two-dimensional joint inversion;after finding the structure of the discrete model,multiple iterations to obtain the best mismatch ratio,determine the size of the parameter and the range of trust based on the test results Select the value of the ? parameter.In the numerical simulation test,the more commonly used high-density resistivity tomography and surface CT method are used for simulation experiments.Based on the professional geophysical inversion library pygimli and the DC method library Bert in the popular python language,it is realized by programming.For the two methods of tomography,the two models are firstly subjected to separate forward calculation and inversion imaging,and the results are compared;then based on the cross-gradient function,reprogramming and joint inversion are performed,and the same model is used to obtain The results of the joint inversion are compared,and the results show that the effect of the joint inversion is more accurate.The compiled inversion python program was used to jointly invert the measured high-density resistivity tomography and seismic CT data of the dam.The inversion results were compared with the separate inversion results of the two methods,and the combined inversion was summarized.The results of the simulation are more accurate,with high recognition and small errors.