Geotechnical Evaluation of Pumps Foundations - A Case Study from Palamuru-Rangareddy Lift Irrigation Scheme, Telangana, India Jain Prasnna1, Naithani A.K.1, Rawat D.S.1, Singh L.G.1 1National Institute of Rock Mechanics, Bengaluru, Karnataka Online Published on 24 January, 2024. Abstract The Palamuru-Rangareddy Lift Irrigation Scheme (PRLIS) is being constructed to lift water in five stages by pumping it from the foreshore of Srisailam reservoir on the Krishna River (FRL +269.735 m) to K.P. Lakshmidevipalli reservoir (FRL +670 m) in Telangana State. Underground pump house caverns are being built to lift 2.0 TMC of water per day for 60-days during flood season in five stages (I, II, III, IV, and V). For the installation of 10 Nos. pumps of 145 MW capacities each, foundation grade engineering geological mapping and geotechnical investigations were done concurrently with the excavation of the pump house for Stage-II of PRLIS. Rock mass categorization of the pump pit foundations were done which are based on engineering geological mapping and geotechnical data gathered from fieldwork and laboratory experiments. The assessment of RMR for granitic rock masses, based on the rock joints and their nature, drill holes and laboratory test data has been done while the weathering grade has been defined based on ISRM method. Grey and pink granites and granitic gneiss of Archaean age were mapped. Along the discontinuities visible on the surfaces of the pump pits floor region, no signs of faulting or shearing were seen. According to the classification of weathering grade, the floor rock mass was divided into fresh and slightly weathered (W-I to W-II) zones. Allowable bearing pressure was estimated from rock mass classification, RMR, RQD and core strength. Engineering geological and geotechnical data were used to recommend and establish acceptance standards for the foundation grade levels for the installation of 10 pumps with 145 MW capacities each. Top Keywords Engineering Geology, Foundation Mapping, Lift Irrigation Scheme, RMR Classification. Top |