This project is for the construction of the underground cable entry shaft with a cable entry basement constructed at the top of the shaft to facilitate cable entry into the cable basement of existing substation. The project includes the two mined adits connecting the proposed cable entry shaft to the existing cable tunnel.
The proposed underground cable entry shaft of 9.5m internal diameter shall be formed by diaphragm panels to approximately 63m below ground. Excavation within the shaft shall be carried out to be about 57m below ground.
The main adit with 5m ID and 29m length connecting the cable entry shaft and gradually reducing to 3.5m when it connects to the existing cable tunnel. a branch adit of approximately 3.5m ID measuring 13m shall be mined off from the main adit to connect to another section of the cable tunnel.