A Simple Criterion for Zoning the Ground Hole Occurrence in the Basic Studies of Railway and Power Transmission Networks in the County of Abarkouh, Yazd

This study has been carried out in the alluvial fan of Abarkouh. The magnitute of the ground holes in the studied area is up to one tenth of a hectare, and their depth is up to about 10 meters. In most cases, this phenomenon is hidden under the ground surface. The purpose of this study is to find a simple criterion from a few indicators and by soil sampling to identify the potential of land for the occurrence of holes. The findings are believed to of help in land management and land use. In this research, integrated land surface observations were combined with the quantitative methods of geoelectric surveys, common soil chemistry, and physics tests. A 400-meter-long route was studied along the Abarkuh shrubs with a geoelectric device, small and large cavities underneath the surface were identified, and the images of the susceptible sites were prepared. Then, in the direction of the geoelectric route and with the difference of micro relieves in the region, some samples were taken from the depth of 0 to 30 cm. Then, a diagnostic criterion was obtained for sensitivity zoning. This criterion was calculated from the geometric average of three parameters including the electrical conductivity, the frequency of effective ions in divergence to calcium extracted from a one-to-five ratio of soil and water, and the liquid limit. The evaluation of the railway lines under construction in Yazd-Eghlid and the power transmission networks indicated that almost the entire rail lines in the Abarkuh area and a part of the route of the power pylons are located in a  high-sensitivity zone.