21. Most cuttings are in earth or rock, but some have concrete lining or stone pitching in parts. 22. To avoid such issues, the National Rail Administration chose to instead build the tunnel with concrete lining . 23. These buildings have walls 2 feet 3?inches thick and floors of concrete lined with timber flooring. 24. The somewhat haphazardly constructed channel is described as being either concrete lined , " composite ", trapezoidal, or riprap. 25. Langdon might describe today's suburbs as endless corridors of concrete lined with parking lots and gaudy-looking, colorless buildings. 26. Large chunks of concrete lining fell from the ceiling and walls of the tunnel, further complicating rescue efforts. 27. One of the longest concrete lined canals in the world, it has changed the desert's face around Ganganagar. 28. Permanent supports have been provided by a concrete lining of varying thickness depending upon the stability of the ground. 29. Along much of its length the creek is a combination of covered channel and an uncovered concrete lined trench. 30. The tunnel was blasted through Limestone, Dolimitic Conglomerate and Keuper Marl and lined with a 375mm thick concrete lining .
