Case Studies

REPAIR/IMPROVEMENT OF ROADS WITH GEOSYNTHETIC

Triveni Constructions, Kolhapur
Kandalgaon Road ODR- 90Km 0/000 to 4/300, Tal-Karveer, Dist-Kolhapur

Improvement to Road from SH to Kandalgaon Road ODR- 90Km 0/000 to 4/300, Tal-Karveer, Dist-Kolhapu

Introduction

TechFab Metal Gabion was suggested for retaining and erosion control purposes in lieu of the conventional R.C.C Retaining Wall for achieving the following advantages:

1. Flexible structure which can accommodate differential settlement.

2. Free draining structure with no pore pressure development behind wall.

3 Easy in construction, as it does not require skilled laborers.

4. Does not require curing time as in case of R.C.C Retaining wall.

5. Eco-friendly, as the vegetation growth over it, is compatible with surrounding environment.

6. Does not corrode under areas which are in constant / partial submergence.

7. Cost incurred is very less compared to R.C.C Retaining Wall and depends only on the local availability of boulders.

Cost incurred is very less compared to R.C.C Retaining Wall and depends only on the local availability of boulders.

Problem Description

Road from SH to Kandalgaon Road ODR- 90Km 0/000 to 4/300, Tal-Karveer passes through rich black cotton soil having a very low CBR value and erosion occurred due to cross-drain & pond. The road was subjected to heavy vehicular traffic intensity because of State Highway and was also

surrounded by the irrigable land on both sides. With the onset of monsoon the road got heavily water logged and due to the existence of the black cotton soil and high traffic intensity certain stretches of road got heavily distressed with significant settlement, unevenness & fatigue cracks. Black cotton soil contains montmorillonite mineral, because of which the soil becomes very slushy when in contact with water and gets brittle on drying. These alternate cycles of wetting and drying makes the highly unsuitable for any type of construction. Flexible pavement designed over this type of soil requires very high crust thickness, which makes it uneconomical. Maharashtra Rural Road Development Association (MRRDA), thereby awarded the Improvement to Road from SH to Kandalgaon Road ODR- 90Km 0/000 to 4/300, Tal-Karveer, and Dist.- Kolhapur respectively

Solution Proposed

TechFab (India) Industries Ltd suggested the use of TFI – 5300 Type-I for the sub grade stabilization of the existing road stretches comprising of black cotton soil, high traffic intensity & water logging.

TFI – 5300 Type-I are polypropylene woven geotextiles with slit-film (tape) yarns in the warp and
fibrillated tape yarns in the weft direction. These engineered geotextiles are stabilized to resist
degradation due to ultraviolet exposure and are resistant to commonly encountered to commonly
encountered soil chemicals, mildew & insects, & are non-biodegradable. Road has been left for
traffic after completion of WBM. There is no settlement seen from last one month.

Techfab also suggested the use of TechBox Metal Gabion as retaining structures for the protection against the water body. Gabions can take settlement which may occur in such regions. TechGeo Nonwoven Geotextile PR 20 was placed at the rear end of gabion wall which acts as filter.

Gabion construction is fast and can be done using unskilled labors. Boulders are available in the
vicinity, reduced the overall project cost and make the project very cost effective. Excavation for
minimum 1 meter depth was carried out in the virgin soil. Any unsuitable soil removed and

replaced with good quality soil. Nonwoven Geotextile are used beneath and behind the Gabion
wall for filtration purpose. Compacted filling was proposed and being carried out at site. Final
batter as per the design was achieved after the completion of the work.

Execution On Site

The existing road at the said stretches was first dressed to get the required cross slope, over which 200mm of murrum layer was laid. Water Bound Macadam (WBM) consisting of 40/60 metal was laid in two layers for a total of 225mm thickness. TFI – 5300 Type-I was then laid over the prepared surface in a tight condition, so that it can develop the required tension. Burnt Bitumen Macadam (BBM) of 75mm thick and asphalt carpet 20mm thick was laid over the same.

CONCLUSIONS

Improved lateral confinement of aggregates
Distributes load over a larger area
Increase in bearing capacity & shear strength of sub grade
Reduction in sub base thickness
Increase in life of pavement

Related Products

TechFab Metal Gabion