Rehabilitation of heavy traffic road through Karnataka forests
|System Offered||StrataWeb® geocell|
|Application||Load Bearing Application facility for movement of heavy vehicles.|
|Project Execution||December 2012|
State Highway 30, managed by the Karnataka PWD is a vital link between Goa and the Uttar Kannada region. The road traverses through lush green forests, and is surrounded by natural beauty. However the area is populated with sugar factories; and this road carries heavy traffic of agricultural produce to and from these factories.
The sub-base soil in the area is rather weak and with poor drainage characteristics. Furthermore, the region experiences heavy rainfall, and water accumulation was a constant challenge. As a result, the surface of the highway is undulating and carries pot-holes.
Problem and Objective
Strata Geosystems (India) Pvt Ltd was approached by PWD, Karnataka to resolve these issues for a section of the highway between Anmod and Belgaum. Considering the time factor, economy and technical issues, a StrataWeb® engineered solution was finalized. To add to the challenge, the road stretch which was awarded was located at the base of a slope where water accumulated the most.
The work was executed during December 2012. StrataWeb® geocell, Style SW3515 in panels measuring 2.6m X 5.6m were used. The 2.6m direction was placed transverse to traffic movement while 5.6m was placed along the traffic movement.
The existing surface of the road was scarified and the StrataWeb® panels were placed in position. Since the work site was in the midst of the forest, transportation of material over long hauls was a challenge. The StrataWeb® system was designed considering local material. The material was laid over the StrataWeb® by tippers and infilling of the StrataWeb® was done both manually and with the help of a front loader and tippers. Once the infilling was completed, the surface was levelled with a vibro-compactor. Considering the dense forest and the isolated route there was no by-pass for the traffic and while the work was in progress, the road could not be cordoned off. The traffic movement was permitted on half the road while the work was carried on the other half, and vice versa.
The Mechanics of StrataWeb®
Cross Section of StrataWeb™geocell
StrataWeb® filled with cohesionless material form rigid mats capable of distributing imposed loads over a larger area. In terms of analyses and designs, the systems are rather complex to assess. The mechanics of how a StrataWeb® system works is explained below in a simplified manner.
When a vertical pressure q₀ is exerted on the non-cohesion fill within the StrataWeb® geocells, lateral stresses are generated. Since all the StrataWeb® cells are filled with non-cohesive material, deflection of the StrataWeb® walls are negligible. Hence the lateral stresses thus generated equal to about (k₀ * q₀) in all cells, where k₀ is the “at rest” earth pressure coefficient for the in-filled non-cohesive soil. This increases shear strength of the confined soil within the StrataWeb®, and lateral stresses are generated in congruent cells as reaction. This effect creates a stiff mattress which contributes to distributing the load over a larger area. Hence the pressure below the StrataWeb® system, p is lower than what they would be through a conventional load transfer system. Hence heavy loads are spread and can be safely transmitted onto weak foundation soils without distress.
This effect creates a stiff mattress which contributes to distributing the load over a larger area. Hence the pressure below the StrataWeb™system, p is lower than what they would be through a conventional load transfer system. Hence heavy loads are spread and can be safely transmitted onto weak foundation soils without distress.
Benefits to Clients
Use of StrataWeb® proved to be a rapid and successful solution, and smooth movement of heavy vehicles was restored with hardly any downtime. The traffic movement was with increasing speed which improved overall productivity and fuel efficiency.
The StrataWeb® solution is fast and an all-weather installation solution. No skilled labour is required. Installation is rapid and local material could be used as the non-cohesive infilling. These factors resulted in substantial savings in money and resources.
Strata Geosystems (India) Pvt. Ltd.,established in 2004, is a joint venture with Strata Systems Inc., USA (part of the 130 year old Glen Raven Group of Companies).Strata Geosystems provides end-to-end technical solutions, from design to execution of geotechnical applications such as reinforced soil walls (flyovers, road over bridges etc.), soil embankment stabilization, reinforced steep slopes, reinforced foundations, slope protection, load support for paved and unpaved roads and bearing capacity improvement, landfills and reservoirs. Strata is reputed for its quality and cost effectiveness and manufactures conforming to strict international quality standards. Its committed team of experienced design and project engineers ensures timely and accurate installation.