![Fig. 15.87, shows the cross - section of railway tunnel. The radius OA of the circular path is 2 m. If AOB = 90^∘ , calculate the perimeter of the cross - section. Fig. 15.87, shows the cross - section of railway tunnel. The radius OA of the circular path is 2 m. If AOB = 90^∘ , calculate the perimeter of the cross - section.](https://haygot.s3.amazonaws.com/questions/973704_95aa703aa3bf4a3ca2100925a306e09b.png)
Fig. 15.87, shows the cross - section of railway tunnel. The radius OA of the circular path is 2 m. If AOB = 90^∘ , calculate the perimeter of the cross - section.
![PDF] A study on the selection of optimal cross section according to the ventilation system in TBM road tunnels | Semantic Scholar PDF] A study on the selection of optimal cross section according to the ventilation system in TBM road tunnels | Semantic Scholar](https://d3i71xaburhd42.cloudfront.net/d5a2f201b10cecf3dbd271b105080d7d079dbe50/3-Figure2-1.png)
PDF] A study on the selection of optimal cross section according to the ventilation system in TBM road tunnels | Semantic Scholar
![The cross - section of a perpendicular to its length is a trapezium ABCD as shown in the figure also given that :AM = BN; AB = 7 m; CD = 5 The cross - section of a perpendicular to its length is a trapezium ABCD as shown in the figure also given that :AM = BN; AB = 7 m; CD = 5](https://dwes9vv9u0550.cloudfront.net/images/2847843/ee825a30-c8f7-41c1-844a-444fadfda260.jpg)
The cross - section of a perpendicular to its length is a trapezium ABCD as shown in the figure also given that :AM = BN; AB = 7 m; CD = 5
![A numerical study on smoke movement in a metro tunnel with a non-axisymmetric cross-section - ScienceDirect A numerical study on smoke movement in a metro tunnel with a non-axisymmetric cross-section - ScienceDirect](https://ars.els-cdn.com/content/image/1-s2.0-S0886779817302985-gr2.jpg)
A numerical study on smoke movement in a metro tunnel with a non-axisymmetric cross-section - ScienceDirect
![Analytical solutions for collapse mechanisms in tunnels with arbitrary cross sections - ScienceDirect Analytical solutions for collapse mechanisms in tunnels with arbitrary cross sections - ScienceDirect](https://ars.els-cdn.com/content/image/1-s2.0-S0020768309003709-gr4.jpg)
Analytical solutions for collapse mechanisms in tunnels with arbitrary cross sections - ScienceDirect
![Cross Section for Tunnel - MX Input File - OpenRoads | OpenSite Forum - OpenRoads | OpenSite - Bentley Communities Cross Section for Tunnel - MX Input File - OpenRoads | OpenSite Forum - OpenRoads | OpenSite - Bentley Communities](http://communities.bentley.com/resized-image.ashx/__size/550x0/__key/CommunityServer-Discussions-Components-Files/5922/8562.Tunnel.jpg)