SUB-SURFACE INVESTIGATION BY RESISTIVITY SURVEY FOR HILL ROAD PLANNING

Abstract

The planning of road construction in hilly areas is an important and difficult task due to rough terrain, scarce availability of desired type of construction material, stable side slope etc. There are various locations in hilly areas which are prone to land slides and rock falls. If road is constructed over these areas, it requires high maintenance cost throughout the year High Water Table also causes many problems like settlement, frost action land slide and thus affects the stability of the pavement. The location of suitable site for bridge foundation is also necessary. Therefore, the sub-surface investigation for efficient planning of hill roads is essential. However the investigation should be quick and economical. Of the several methods of sub-surface investigation the geophysical method especially, electrical resistivity method has been found to be most suitable. In the present study vertical electrical sounding (VES) has been carried out in a hilly region between Rishikesh and Dehradun of Uttar Pradesh. VES data have been interpreted to generate geological section and assessing depth of water table. These information were used for the critical analysis of two routes with respect to their material, drainage and foundation characteristics. Technology gap have also been identified and recommendation for the future studies has been pointed out.