Ground improvement for Reinforced Soil wall for ROB

Ground improvement for Reinforced Soil wall for ROB

Location ROB 208, Arjungunj, Uttar Pradesh
Principal Client U.P. State Bridge Corporation Ltd
Application Ground improvement work for Reinforced Soil Wall Embankments
System Offered StrataWeb®
Project completion October 2013

Background

UP State Bridge Corporation Ltd., Bridge Construction Unit – 2, Lucknow, was seeking a solution for the ground improvement for construction of Reinforced Soil wall for ROB 208 Arjungunj, U.P., India. The approach was designed for a maximum height of 10m.

Objective

The sub-base soil in the area was rather weak with a low bearing capacity but providing conventional solutions of soil replacement, stone columns, PVDs and other such techniques was not warranted and would have had made the structure commercially unviable. A ground improvement solution was sought which would be rapid to implement, and at the same time, cost effective. Strata India was awarded the work including to design, supply and install the StrataWeb® system.

Strata Solution

The ROB exerts a maximum load of 310kPa. In addition to this, the allowable long-term settlement was restricted to 100mm. Considering the technical parameters, time factor, and economics, a StrataWeb® geocell engineered solution was finalized.

Two layers of StrataWeb® SW 351 100, were proposed where the RS wall height was 10m and up to the 4m. For ramp height less than 4m, a single layer of StrataWeb® was proposed. The local non-plastic soil was selected for infilling.

Construction Overview

The work was initiated in September 2013 and was completed before the stipulated time period. The existing surface of the road was excavated up to a depth of 1.45m to incorporate the ground treatment, including the mandatory requirement of 1m embedment of foundations for the RS Walls. After levelling and dressing the excavated ground surface, a layer of polypropylene (PP) non-woven geotextile was laid at the base followed by a layer of StrataWeb®. StrataWeb® was then filled up with the approved soil with a top-up cover of 100mm and compacted to the extent possible. The infilling of the StrataWeb® was done using a conventional front loader. Once the infilling was completed, the surface was levelled and further compacted with the help of a vibratory compactor. The second layer of StrataWeb® was placed above this soil layer and the same process was repeated. The second layer of StrataWeb® was not required for height of RS walls less than 4m.

Benefits to Clients

Use of StrataWeb® proved to be a rapid and successful solution, improving the bearing capacity to the desired levels. This enabled the construction of RS Wall ahead of schedule.

The StrataWeb® solution is fast and an all-weather installation solution. Benefits such as lack of requirement of skilled labour, rapid Installation and use of local soil, all converged to provide substantial savings in money and resources for the client.