Geoanalytical approach in locating and ezecuting spillway structures of Tehri dam, in Uttarakhand Himalaya, India
Spillway stluctures are real saviours for the earth and rock fill dams and in case of giant structures like Tehri dam, their safe and timely completion is of paramount importance because it is indelibly linked with the reservoir filling and commissioning of the project. Selecting the sites for locating the different surface and underground spillway structures, was a daunting task but due to beforehand information of geological features, no geological surprises were encountered during construction in such a colossal project despite its location in the complex geological regime, geodynamically active and seismically sensitive Hi- malayan region. Use of geoanalytical approaches like the innovative block tectonic model, kinematic check and 2D/3D analysis helped in identifying the possible failure modes and in anticipating geotechnical problems at different structures. Resting the foundation of guide wall of the approach channel of chute spillway, planar failure along the foliation joints and longitudinal (L) shears due to day-lighting along chute spillway, a wide zone of deformed rock mass formed by the intersection of the major diagonal shear (D-l) and longitudinal shear seams at the junction of the chute and stilling basin, poor rock mass around D-3 shear (near T-4 shaft) and multiple shear seams as projected along T3 shaft, high stress concentration at the junction of the main shafts with the de-aeration ducts because of the reverse curve geometry, excavation of the inclined glacis of ILO at the junction with T-3 shaft and occurrence of highly unstable material like slump mass on the slopes below the right bank shaft spillways were the major geotechnical problems encountered. The geotechnical inputs were pivotal in deciding the excavation sequence and stabilization measures/support system of different surface and underground spillway structures.
P.C.Nawani Harish Bahuguna H.C.Khanduri
National Institute of Rock Mechanics,Kolar Gold Fields,563117,Karnataka,India Geological Survey of India,Dehradun,248006,Uttarakhand,India
国际会议
International Symposium and The 7th Asian Regional Conference of IAEG(国际工程地质与环境协会年会暨第七届亚洲工程地质会议)
成都
英文
156-164
2009-09-09（万方平台首次上网日期，不代表论文的发表时间）