Notes on Tunnel Construction Lecture

Overview

Major tunnel project for Deutsche Bahn in Stuttgart.
Blasting occurring 20 meters beneath the city.
Tunnel construction is intense and requires improvisation due to unexpected challenges.

Machines: Two TBMs named Wanda and Sibylle.
Length of Tunnel: Over 8 kilometers, one of Germany's longest tunnels.
Cutter Head Wheel: 12-meter diameter, weighs 200 tons, uses 140 spade cutters.
- Rotates at 2.7 RPM, pressures up to 400 bar, can loosen 20 meters of rock per day.
Loading Process: Crane (1,200 tons, 90 meters tall) crucial for lifting cutter head wheel.
- Assembly took five weeks, crane operator responsible for safety.
- Massive eye hooks and 60 kg iron bolts used for securing.

Crane Issues: Crane brake malfunction delayed operations.
- Express delivery for spare parts awaited.
- Cranes highly expensive; operational costs are significant.
Access Shafts: 40 meters deep, used for transporting materials in and excavation out.
- Portal crane can lift 60 metric tons; 50-60 dumpsters moved daily.

Process: Controlled explosions used to excavate rock.
- Requires careful planning and respect for vibration limits due to proximity to buildings.
- No blasting allowed from 10 PM to 6 AM.
Materials: Approximately 90 kg of explosives used per blast, detonators graduated for limited vibrations.
- Inspections and ventilation needed post-blast for safety.

Conventional Excavation: Focus on ensuring safety and precision.
- Use of specific machinery (excavators, shotcrete machines) tailored for deep mining was highlighted.
Tunnel Structure: Concrete rings (7 segments per ring) are installed after excavation for structural integrity.
- Mortar pumped to fill gaps between rings and rock
Continuous Operations: 24/7 working schedule to minimize downtime and maximize efficiency.

Duration: Alpvorland tunnel construction estimated at 18 months.
- Progress monitored carefully, adaptability required due to unforeseen issues.
Future Outlook: Multiple tunnels planned around Stuttgart to facilitate high-speed trains.

Repair and Maintenance: Ongoing repair work for machinery, especially transport vehicles.
- Spare parts and a dedicated team needed for maintenance tasks.
Emergency Protocols: Strict protocols in place for handling explosives and machinery operations.

Tunnel construction is highly complex, involving both technical precision and safety protocols.
- The project requires collaboration among engineers, construction workers, and technical staff to ensure timely progress and safety.