Study And Evaluation On The Observation System Of 3D High Density Resistivity

The apparent resistivity value of the profile obtained by 2D high density resistivity method is a comprehensive reflection of the non-uniform electric field in a terrain and underground range.This method can guarantee a high accuracy when adopted for detecting,and it has been widely used for dam flaws detection,landslide surfaces detection,deep hole curtain grouting inspection,and underground pipeline detection,etc.However,it is normally required to determine their precise location and size such as exploration of caves,blocks,contaminated areas,burial chambers,etc.,making it difficult to determine whether anomalous reactions of 2D exploration results are affected by side effects of 3D geological bodies.3D high density resistivity method can effectively remove the side effect and achieve accurate positioning and full perspective of the target body.However,due to the conventional observation method requiring all electrodes to be arranged at one time,putting high requirements on instrument and costs are very high,which greatly limits the application of this method.Therefore,it is of great theoretical and practical significance to spread the application of 3D high density method by improving the conventional one-time array layout.In view of this,the pole-pole configuration is taken as an example to quantitatively study the data uniformity of complete survey,cross-diagonal survey and ? survey.The forward modeling method is used to quantitatively analyze the resolution capacity of abnormal body with different survey methods.M+N electrodes are used to achieve the data acquisition,covering an M×N electrode grid,with the roll-along technique.Considering both economy and efficiency,combined with the above data uniformity,resolution capacity,time,and cost,the TOPSIS method is adopted based on multi-attribute decision-making theory to quantitatively evaluate different combinations of electrodes,survey methods and roll-along patterns,to obtain the best combination and provide reference for engineering applications.