Influence of Vertical Seismic Coefficient in Seismic Analysis of Hydro-Tunnel in Rock

Abstract

As a result of increased urbanization and the need for better infrastructure, the scope of tunnel projects is also expanding. The country has much potential for hydropower, and the hydropower sector has produced the most tunnels. Hydro projects have some of the country's longest tunnels. In the Himalayan areas, almost 75% of the full potential for hydropower production is concentrated. Himachal Pradesh has the most projects with a total tunnel length of 500 km, followed by Uttarakhand (160.8 km) and Jammu and Kashmir (135.14). Due to geographical and geological difficulties, tunneling in the Himalayan area is extremely difficult. Due to geological issues such as sheared rock, high water intrusion, and high geothermal gradient, long hydro-tunnels have experienced time and expense overruns. Extensive studies must be conducted to use the hydropower potential fully, the appropriate technique must be adopted, and risks must be adequately identified and managed. Geological prediction during tunneling should be standard practice to reduce geological uncertainty and prevent unanticipated hazards. To complete a project on schedule and safely accurate evolution, analysis, and interpretation of rock mass quality play a key role. This paper provides a numerical analysis of the seismic response of a circular lined tunnel running through a jointed rock mass. The effect of tunnel depth, frequency, and peak ground acceleration on the axial force produced in the tunnel liner is studied. The outcomes of the numerical computation have verified the patterns of seismic damage observed in the past. © 2023, Indian Society of Earthquake Technology.