1. What is this?

2. B6
580 Tonne
Tunnelling Machine
Money from sale went to charity
Tony Wilkinson (scrap metal dealer)
£39,999 (Stedman)
£250,000 removal
£39,899

3. Key Question: Why are tunnels and cuttings subject to landslides?
Click on photo for video
Key Words:
Overbreak
Ground squeezing
Rock bursting
Slip planes

4. Reasons why tunnels are prone to collapse
Overburden Pressure
Pressure from rock above
Rockfall
Overbreak
Rock Bursting
Groundwater inflow
Ground Squeezing

5. Tunnel Problems: Key Definitions
When too much material is extracted from a tunnel and it may collapse e.g. when blasting granite
Over break
When the sides of the tunnel collapse inwards due to the surrounding pressure
Rock Bursting
Budging upwards of the tunnel floor
due to pressure
Ground Squeezing
Water entering the tunnel due to permeable rock (limestone / sandstone) and structures such as faults and joints.
Groundwater Inflow
Rock Fall
When rocks fall in from above