Geology of 640MW Azad Patan hydropower project District Sudhnati (Azad Kashmir) with especial emphasis on structural & engineering geology of its diversion tunnel (P-0882) (MFN 3250)

Abstract

Azad Patan was potential hydropower site identified in late 80’, on river Jhelum. WAPDA under Water Vision 2025; initiated different private – public partnership hydroelectricity generation projects in the country to meet growing future demand. Alamgir Powers started feasibility studies for Azad Patan hydropower project under such private – public partnership scheme. The project is located on the western limb of Hazara – Kashmir syntaxis and mainly composed of continental origin Murree formation. A diversion tunnel route is proposed for river diversion during current geological and geotechnical studies. Rock cores physical examination reveals that the unconfined compressive strength for sandstone varies from 20.28 to 184.96 MPa, argillaceous sandstone 2.18 MPa, siltstone 21.24 MPa, claystone14.41 to 50.50 MPa and silty-claystone13.89 MPa. The poisson ratio varies for sandstone from 0.05 to 0.51 MPa whereas, that of argillaceous sandstone 0.204 MPa and the modulus of elasticity varies for sandstone from 9750 to 25500 and of argillaceous sandstone 9880. Based upon Bieniawski's 1989 rock mass rating, sandstone is classified as class III fair and the location is considered suitable for diversion tunnel.