Solved Tunnel Problem Exercise 7 You are going to build a
The shaft is 200 ft. deep to the invert of the tunnel and 22 ft. excavated diameter. The tunnel is 25 ft. excavated diameter in competent sandstone and limestone. The profile of the shaft is as follows: From the surface down- 20 feet of fill; 30 feet of sand and clay; 20 feet of silty gravel; 50 feet of limestone and 80 feet of sandstone.