Engineering Challenges: Building Tunnels

Engineering Challenges: Building Tunnels — page 3
6 For this reason they designed caverns with colored lights These caverns are every 3 7 miles 6 0 km They are meant to help people stay alert Suddenly Anna's grandfather pulled into a parking bay and the three got out of the car They were standing under a mountain A tunnel is a long narrow path under the ground Tunnels are some of the most challenging projects in engineering and construction Engineers spend a lot of time planning them They must determine a route study the ground and design the excavation method and support Years may pass between the idea of the tunnel and when construction begins