The growth of many cities has resulted in the need for increased infrastructure. As urban space becomes more limited, subsurface structures such as tunnels are becoming more efficient in providing the required infrastructure. The tunnels are defined as the artificially constructed underground passageway underneath a barrier such as stream or other bodies of water, hill, or other earthen structures, or a building. That are mainly used for transportation purposes. These permit the transmission of passengers and freights, or it may be for the transportation of utilities like water, sewage or gas etc.The operations and the constructions are carried out underground without disturbing the ground surface. In all cases a tunnel has a minimum of two openings, one for entry and another for exit, depending on the point of ingress and egress. Tunnels can be built through rock, soil, or a combination of both in either an open cut/ cover arrangement or by means of mining using drill and blast, tunnel boring machine, or other sequential excavation methods. There are different types of tunnels. For example road tunnels, railway tunnels etc Road tunnels or vehicular tunnels are a closed or roofed structure carrying a road through or under an obstacle. This obstacle may be anything in the path of a preferred road alignment such as a mountain, a body of water, a building or a complete development. Road tunnels as defined by the American of state highway and transportation officials (AASHTO) technical committee for tunnels are enclosed roadways with vehicle access that is restricted to portals regardless of type of the structure or method of construction. Road tunnel in the United Kingdom is defined as "a subsurface highway structure enclosed for a length of 150 meters (490ft) or more. In the United States, the NFPA definition of a tunnel is “An underground structure with a design length greater than 23m (75ft) and a diameter greater than 1,800 millimeters (5.9 ft).It satisfy environmental or ecological requirements. In addition, road tunnels are viable means to minimize potential environmental impacts such as traffic congestion, pedestrian movement, air quality, noise pollution, or visual intrusion; to protect areas of special cultural or historical value such as conservation of districts, buildings or private properties; or for other sustainability reasons such as to avoid the impact on natural habit or reduce disturbance to surface land.At the same time road tunnels are some of the most expensive parts of road infrastructure but in some cases.they are necessary to overcome circumstances where other solutions cannot be applied.With the growth of urban populations, the increase in number and size of mega cities and reverse migration to cities, tunnels are more frequently the answer to congestion problems. The largest road tunnel in ancient times was constructed between Naples and Pozzuoli, in 36.BC.This tunnel was 4800-foot-long, 25 foot-wide and 30 foot in height. By the 20th century, trains and cars had replaced canals as the primary form of transportation, leading to the construction of bigger, longer, tunnels.During the second half of the twentieth century, the development and progress of explosives and sophisticated equipment were flourished, that made the tunneling process more feasible. The Holland tunnel completed in 1927, was one of the first roadway tunnel and is still one of the world's greatest engineering projects. In India, road and rail network are one of the largest transport network in the world and bridges, tunnels play a major role to complete the connectivity across the country. Most of the tunnels in India are located in Western Ghat and Himalayas ranges.The Rohtang tunnel is the world's highest road tunnel situated under the Rohtang pass of eastern pir panjal range of the Himalayas on the Leh-Manali highway in Himachal Pradesh.The chenani-Nashri tunnel is the India's longest road tunnel (9.28 km) under construction in Udhampur district of Jammu and Kashmir.It is also one of the longest tunnel in Asia. In Kerala, Kuthiran tunnel is an under construction tunnel in kuthiran in Thrissur district.When finished, it will be kerala's first -ever tunnel for road transport.The pragati group was subcontracted the work by the Hyderabad -based company.Pragathi bagged the subcontract at a cost of Rs 200 crore. The present study is to identify the favorable and unfavorable conditions for Kuthiran tunneling.In addition it mainly focuses on understanding the tunnel making impact and consequences faced by people in Kuthiran.
