从图6和图7中可知，与空气电阻率对比度越大，半空间效应越明显，当深度大

It can be seen from Figure 6 and Figure 7 that the greater the contrast with air resistivity, the more obvious the half-space effect. When the depth is greater than 10m, the impact of the half-space effect is already very small and has little impact on the inversion; when the depth is greater than 20m When , the half-space effect can be ignored. Therefore, when inverting the measured data, there are two options. One is to establish a model containing the air layer for inversion calculation. However, due to the large resistivity contrast, the calculation is difficult. The inversion is not easy to converge; the second method is to only conduct inversion calculations for strata below 10m, which is acceptable in engineering because caves are usually developed in bedrock layers below 20m.

From Figures 6 and 7, it can be seen that the greater the contrast with air resistivity, the more obvious the half space effect. When the depth is greater than 10m, the influence of the half space effect is already very small and has little impact on inversion; When the depth is greater than 20m, the half space effect can be ignored. Therefore, there are two options for inversion of measured data. One is to establish a model containing an air layer for inversion calculation. However, due to the high contrast of resistivity, the calculation is difficult and the inversion is not easy to converge; The second method is to only perform inversion calculations on layers below 10m, which is acceptable in engineering because karst caves are usually developed in bedrock layers below 20m.

As can be seen from Figures 6 and 7, the greater the contrast with air resistivity, the more obvious the half-space effect is. When the depth is greater than 10m, the half-space effect has little influence on inversion. When the depth is more than 20m, the half-space effect can be ignored. Therefore, there are two schemes for inversion of measured data. One is to establish a model containing air layer for inversion calculation, but the inversion is difficult to converge because of the large resistivity contrast. The second method is to carry out inversion calculation only for the strata below 10m, which is acceptable in engineering, because karst caves usually develop in the bedrock below 20m.