Abstract:
Swat Expressway is an 81 kilometre long four lane under construction highway in the
Khyber Paktunkhwa province of Pakistan. It stretches from Nowshera to Chakdara in
Lower Dir. The project was inaugurated in August 2016. The project will be of high
value to China Pakistan Economic Corridor and is expected to be completed in 15
months.
During the initial geotechnical investigation of the site, it was found near bakhshali
interchange that water table is only 1.5 meters below the ground surface which
would certainly lead to excessive settlement if no arrangements to solve the issue
were made. Saturated soils have a long consolidation period due to permeability and
it must be reduced to a considerable amount to allow the construction of highway.
There are a number of techniques used to improve such grounds which include sand
drains, stone columns, cement grouted piles, chemical stabilization and many more.
Out of various available techniques three techniques (Sand drains, Stone columns &
Lime stabilization) were chosen to analyze the effect of these techniques on strength
of soil. For the aforesaid purpose, a model was constructed to check the effect of
these techniques on soil bearing strength. Model may be used a number of times for
any type of soil and conditions encountered on site
The authors believe that research on the techniques chosen to solve the problem will
be enhanced by the model constructed where soil strength before and after
application of ground improvement techniques can be tested by scaling down the
site conditions. Research will lead to give the most feasible ground improvement
technique for the encountered site conditions and problems
