DIVERSION TUNNEL DESIGN OF ASAHAN IV DAM, SUMATERA UTARA PROVINCE

• Main Author: Riany K P, Annisa
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/54289
• Institution: Institut Teknologi Bandung

Asahan IV Dam is water building to raise the water level of the river to establish water fall. The construction of the Asahan IV Dam is planned to be part of the construction of a Hydro Power Plant (PLTA) which is a solution for utilizing the potential and demand for electricity in North Sumatra. To realize this project, it is necessary to design an diversion tunnel to divert the water flow during the construction implementation period of the dam and alternative to the emergency spillway for floodwater inflow. The tunnel type used is a mountain tunnel in accordance with the geographic conditions of the location consisting of rocks. The circumvention tunnel design carried out in this final project consists of tunnel capacity, flood tracking, analysis of tunnel loading and stability, calculation of tunnel reinforcement and lining, construction methods, and soil reinforcement in the tunnel walls. An evasion tunnel flood search was conducted using manual calculations and HEC-HMS software. Tunnel load and stability analysis was performed using PLAXIS 2D software to determine deflection, internal force, and safety factor values. The design and calculation of soil reinforcement for tunnel walls is based on SNI 8460 2017 concerning Geotechnical Design Requirements. From the design that has been carried out with a tunnel length which is planned to be 384 meters long, the cross-sectional form is a horseshoe.