The construction of flexible pavement using StrataWeb™ Geocell.
The Major District Road, MDR 31 passes through Shaha and Kolpewadi villages in Sinnar Taluka, District Nashik. It comes under the purview of the Nashik PWD and is an important link connecting the sugarcane producing farms of Sinnar Taluka with sugar mills with heavy traffic during peak seasons.
The Challenge
Common to those parts, the subgrade soil in these areas is basically expansive soil which is colloquially called black cotton soil. During the dry months, the soil is very hard and shrinks, but during the monsoons, it expands and turns very soft. The MDR constructed on untreated expansive soil as subgrade suffered severe undulations. Conditions on these roads deteriorated to such an extent that bus services along these routes had to be discontinued.
Strata´s Innovative Solution
Strata proposed StrataWeb™ geocells within the pavement crust. On the basis of the data provided by the PWD, the CBR of the subgrade in wet conditions was 2.8 per cent. Traffic loading over the life of the road was considered as 5MSA. With these inputs, a road section as per IRC 37-2012 was considered. This section would cater to the imposed load over the forecasted life of the road as well as the poor CBR. But this section would not cater to the expansive and shrinkage characteristics of the subgrade.
To cater to the expansive nature of the subgrade, StrataWeb™ was considered above the subgrade. This proved to be an optimal solution, which also reduced the need for regular maintenance.
The Process
The existing road was scrapped off and the subgrade was dressed and levelled as required and watered and compacted. A layer of sand was placed over the dressed subgrade. StrataWeb™ SW 356-150 panels were placed in position above the sand with the help of metal spikes and infilled with granular sub-base (GSB) material. After the infilling and overtopping by 25 mm with GSB, the surface was levelled and compacted with vibro-compactors. Traffic movement was allowed immediately thereafter.
Value Addition to our Customers
1.The problems of expansive soil were overcome by using StrataWeb™. StrataWeb™ resists uplifts due to expansive soils and bridges over shrinkage voids between the pavement section and the subgrade.
2.The pavement section was stronger than that by conventional design and the riding quality of the road improved.
3.Maintenance costs were reduced.
4.All in all, there were huge savings in time and cost.
Project Details
Location: Shaha Kolpewadi to District Border Road, MDR-31, Sinnar, Maharashtra Client Name: PWD, Nashik, Maharashtra
Contractor: S M Autade Constructions Pvt. Ltd., Mangalwedha, Sholapur, Maharashtra
Project Size: 11,800 sqm (approx.) {2.1 km of 5.6m wide road}
Application: Construction of flexible pavement on expansive soils
System Offered: StrataWeb™ Geocell
Project Completion: October 2014
Leave a Reply
You must be logged in to post a comment.