Tunnels are constructed To avoid the expensive acquisition of valuable built up land, tearing up pavements and holding up traffic for long periods in large cities. When the depth of ordinary cutting exceeds 20m and the ground rises rapidly for a considerable distance after wards. To avoid the excessive cost of maintenance of an open cut subjected to land slides or snow

Pavement considered flexible and the failure mechanism is assumed to be plastic deformation due to the communicative load over the life of pavement. Elastic Deformation: Temporary deforms the foundation material and compresses the air that fills the voids of the base and subgrade. In truly elastic deflection, permanent unevenness does not occur, even under repeated

An opening through an embankment for the conveyance of water by mean of pipe or an enclosed channel. Generally selection and type of material depends on the comparative cost, location of structure, availability of skilled labor, time limitations.

The design should be done so that to meet the above requirements for considerable number of years (need proper design and construction supervision). Pavement meeting all the requirements above have been product if six distinctly different construction processes as follows. Heat a viscous bituminous binder to make it fluid, then in a plant mix it with heated

In meeting oncoming vehicle or passing slower ones, the portion selected by a driver depends primarily on the paved surfaced width of the highway. The width of the surfaced road and the no of lanes should are adequate to accommodate the type and volume of traffic anticipated and the assumed design speed of vehicles.