Abstract

Polavaram multipurpose project, is an under construction power plant on Godavari River in the West Godavari District and East Godavari District in Andhra Pradesh. This study focuses on deformation structures in the powerhouse area and their relationship with rock mass rating (RMR). Garnetiferous gneiss, suites of khondalite, pegmatite and charnockite are the prime rock types of the Eastern Ghat Mobile Belt (EGMB). The power house has two faces viz., the upstream and the downstream faces. During surface mapping, different structural data was collected e.g., joints, shear zones, faults, spacing of discontinuity, condition of discontinuity, uniaxial compressive strength by Schmidt hammer, rock quality designation (RQD), groundwater condition, weathering condition etc. Four joint sets were identified with one random joint; those give the blocky appearance to the rockmass. Pegmatite occur in three episode of intrusion one intruded along foliation with orientation 40–55° dipping towards 220–275° (SW), dipping at 75–80° angle towards 145° (SE), third set of pegmatite intruded obliquely to the foliation i.e. 60–70 towards SW (240°). Three sets of ductile- brittle shear zones were identified. Based on cross-cut relationship they were arranged in chronological order. Oldest shear zones in the area show parallel to the regional foliation in the area and older one dips at 60° towards NE (110°) and youngest one dips moderately (25–40°) towards NW (290°). At some locations anastomosing shear zone also identified and these structure bring the RMR values varies 20–30 and bring the rock mass into poor to very poor class. Based on the surface mapping weathering grade also varies from highly weathered at the top of the hill to slightly weathered towards the foot of the hill at the cutting surface. Overall RMR class varies from very poor at the deformed/sheared zone to fair class in relatively less deformed area.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.