SLOPE PROTECTION WORKS FOR A HIGHWAY EMBANKMENT IN FLOODPLAINS- A CASE STUDY OF GANGAPATH EXPRESSWAY (Paper 784)

Erosion of the river banks during floods or peak rainfall periods have become continuous event causing enormous problem for the people and the Government in the state of Bihar, India. The paper is walking through a case study for a highway embankment „Gangapath‟ along the Ganga River where erosion control and flood protection measures were adopted. River Side Protection works are most critical parameter in the construction of the Proposed Driveway. It is a major element in the design, construction, and maintenance of highways as the embankment is constructed in floodplains nearby large rivers like Ganges. Stone pitching are popularly used for river bank protection preventing erosion of bed and bank during passage of flood. Now-days, stone mattress in wire crated mesh is also being extensively used in place of loose pitching because of several advantages. The methods, materials, soil conditions of the project area, standards for design and selection of systems to mitigate the damaging effects of flowing water on embankment and adjacent properties have been described in detail. Step wise calculations of size and weight of stone and thickness of mattress on sloping and launching apron are provided in the paper so that mattresses provided can resist the erosive forces for stability. The ground improvement works adopted for the construction of embankment on a soft soil is also briefed. The paper is giving an insight into the requirement of developing artificial fills/stones for protection works where natural stone of required properties is not available near the site or stone cost is very high.