Urban tunnels are an unavoidable solution for the development of cities which in long-term will reduce costs and provide direct and indirect advantages to the public. Research has shown a growing tendency towards the use of urban underground spaces throughout the world and Iranian cities are no exception.
The Resalat Highway is one of the longest east-west routes in Tehran. It connects the eastern part of Tehran from Damavand Street to the western part of Tehran at Rah- Ahan residential area. The 1964 meter long Resalat tunnels consist of a long twin tunnel (822 meters) and a short twin tunnel (160 meters) each having three lanes in both directions.
These tunnels were excavated in Tehran’s alluvium with a diameter of about 17 m and only 3.5 m distance between the tunnels. The inside diameters of each tunnel after completion of the final reinforced concrete lining is 13.5 meters. Pre-cast concrete sections (waffles) cover the tunnel walls
The Touhid Tunnel is located within the area of Chamran Highway, Touhid Square, Jomhuri Square, and Navab Highway.
The twin tunnels share a middle interface wall constructed by piles with 1.5 m diameter, spaced by a 4 m interval. The twin tunnels have an excavated cross sectional area of about 305 m2. The total project length (in each direction) is approximately 3000 m which consist of a tunnel comprising of three driving lanes with a length of 2136 m, and one northern and one southern ramp with the total length of 864 m. The total length of the tunnels is 4272 m. The slopes of northern and southern ramps are 6% and 4.29% respectively and the average slope of Tunnel is 4%. The width of the tunnel is approximately 12.5 m, and consists of two 0.5 m wide pedestrian passages at both sides for the utilities service personnel to operate and maintain the tunnel, and three separate lanes and an emergency lane with a total width of 11 m for vehicles. The height of these horseshoe shaped tunnels is 8.5 m.
Connecting the Sadr and Niayesh highways via a twin-tunnel will reduce traffic in the northern part of Tehran. Each of these tunnels is approximately 3650 m long. The alignment starts at the western side of Sadr highway and passes below Africa Boulevard Vali -e- Asr Street and the south side of Mellat Park and reaches the Niayesh highway at the northern part of Kordestan highway. Each tunnel has a height of 11.75 m and a width of 14 m and consists of two traffic lanes and a smaller emergency lane.
The maximum overburden along the alignment is approximately 53 m.
The Fazilat tunnel is part of the Fazilat expressway connecting Saadieh town to the main part of Shiraz. The total length of the project is 1.8 km and the underground part is approximately 650 m long. The tunnel has a northeast-southwest direction and is located southwest of the Mouleh mount crestline .
With a width of 18.96 m and a height of 12.20 m the Fazialt tunnel has one of the largest openings amongst Iran’s Tunnels. This tunnel was excavated using the drill and blast method and in two heading and benching stages.