08-02-2010, 06:47 AM
NEW TECHNIQUES OF EROSION CONTROLS ON HILL ROADS
INTRODUCTION
Transportation contributes all round development of a country and hence plays a vital rate towards its progress. If the highways are not properly located and may contribute sediments to streams. The control of soil and water is basic to the protection of the road structure and therefore highway design, construction and maintenance must be continually evaluated to minimize erosion and sedimentation problems
MECHANISM OF SURFACE EROSION
Rain drops hit the slope surface
Impact of raindrop detaches the particle of soil
The runoff water flowing on slope surface transports the detached particle and may also contribute to further detachment
TYPES OF EROSION
WIND EROSION
RAIN EROSION
Wind Errosion
Exposed slope of non-cohesive loose and dry soil
Lack of shelter from wind
Exposed surface with out any protection
FACTORS CONTROLLING WIND EROSION
Wind velocity
Particle size of the material exposed to wind
Moisture content of soil
Vegetative cover
RAIN EROSION
Rain erosion is phenomenon of transporting of soil particle due to water action, the influencing factors for rain water erosion are
Potential of flowing water for initiating particle detachment
Physical features ie topography, gradient, embankment slope etc
Soil erodibility governed by clay content, particle size distribution, compaction , permeability, shear strength parameters etc of the soil
OBJECTIVES OF EROSION CONTROL
To prevent damage to land adjacent to the road structure
To reduce the soil loss from the land width of road, which silts up drainage channel and pollute rivers
To contribute to the improvement of the aesthetics of the landscape
To protect and preserve the earth work of fill or cut slope, ditches and drainage structure
EROSION CONTROL SYSTEM
TRADITION/ CONVENTIONAL METHODS
Agronomic method
Non-agronomic method
NEW TECHNIQUES “ENGINEER INOVATION
Reinforced vegetation
Coir geotextiles
AGRONOMIC METHOD
Simple vegetative trufing
Mulching of slope
COIR GEOTEXTIL
Made from coconut fiber extracted from the husk of the coconut fruit
It is a biodegradable organic fibre material containing cellulose and lignin
It gives max protection to the soil ES
SOME NEW TRENDS
SILT FENCE
CURLEX QUICK GRASS
STEEL GROUND STAPLES
DE WITT PROSPUN LANDSCAPE FABRIC
POLYPROPYLENE SAND BAGS
CONCLUSION
In all new construction erosion levels should be assessed in advance and appropriate protection measures are incorpoated in design.
In case of existing structures facing erosion problems, both short term and long term measures should be considered to ensure stability. For overall economy use of locally available materials should be the first choice. In extreme climatic conditions polymeric grids with root reinforcing mechanism may be used even though they are costly