Construction of Hill Roads (Retaining Walls, Breast Walls and Parapets)
The retaining walls are the most important structure in a hill road construction to provide adequate stability to the road way , and to the slope.
Fig-01)Retaining walls
The Retaining walls are usually constructed on the valley side of the road way and also on the cut hill side to prevent land slide towards the roadway.
The thickness of the wall at the top is usually kept as 60 cm and at the bottom it may be kept according to the following thumb rule
: For walls in height < 6 m,
the retaining wall at the bottom (thickness) = 0.4 X height.
For walls in height > 6 m ,
the retaining wall at the bottom (thickness) = 0.4 x height +30 cm.
A batter of 1 on 12 may be given to the wall on the outside, The breast walls are constructed on the hill side of the roadway to retain the earth from slippage.
The wall may be kept 60 cm thick throughout and sloped along the natural slope of the earth, it has to protect.
The parapet walls are usually required on the valley side of the roadway to guide the vehicles properly to the roadway.
The thickness of the wall is uniform throughout and 60 cm.
The height is usually kept as 75 cm above the berm level. May be kept as 75 cm above the berm level.
