Open AccessEngineering geology of Kankai Hydroelectric tunnel alignment
Author(s) -
Sunil Kumar Dwivedi,
Prakash Chandra Adhikary
Publication year - 2006
Publication title -
journal of nepal geological society
Language(s) - English
Resource type - Journals
ISSN - 0259-1316
DOI - 10.3126/jngs.v31i0.262
Subject(s) - hydroelectricity , rock mass classification , rock mass rating , geology , siltstone , mining engineering , hydrology (agriculture) , geotechnical engineering , geomorphology , engineering , facies , structural basin , electrical engineering
This paper describes the engineering geological characteristics of rock mass in the headrace tunnel, powerhouse, and intake portal of the Kankai Hydroelectric Project. The project area lies in the Lower Siwaliks of east Nepal and consists of alternating sandstone and mudstone beds with frequent siltstone intercalations. The rock mass of the project area was classified according to rock mass rating (RMR) and rock mass quality index (Q) systems. It is of very poor, poor, to fair quality (categories V, IV, and III) in the headrace tunnel; of very poor quality (category V) in the powerhouse; and of fair quality (category III) in the intake portal. The stability analysis of irregularly jointed and fractured rocks of the area was carried out using SWEDGE and UNWEDGE. The analysis gave the safety factor of 0.45, 0.64, and 0.45, respectively for the powerhouse, intake portal, and headrace tunnel. The final safety factors obtained after the installation of support for powerhouse, intake portal, and headrace tunnel were 1.14, 3.33, and 4.53, respectively.