In order to encourage the use of geo textiles in road construction – a joint Research Project between NEDUET and TIP was initiated with an aim to explore the following two aspects.

•  the degree by which the life of a pavement over soft soils can be enhanced by the use of geotextiles.
• cost savings involved ,both at the time of construction and in terms of overall life cycle of the pavement (maintenance cost).

Soft soil is not suitable for construction because of the problems of high compressibility, low shear strength, low permeability, low bearing capacity and excessive settlement. Therefore, under cyclic loading, soft clayey and silts subgrades exhibit large deformation and thus leading the fine grain subgrade into graded base course.

Usual methods of soft soil stabilization are based on use of stone piles, hydrated lime, cement or cement kiln dust, lime and coal fly ash (CFA) treatment and at times are not effective in the long run. The better option for soil stabilization in road and dam construction is geo textiles. In road construction, geo textiles act as reinforcement element with in a soil mass or in combination with soil to produce a composite with the benefits of stabilization, separation, filtration and compaction. The major functions of Geo textile are stabilization, separation, reinforcement, filtration, drainage and acting as liquid barrier.

The objective of the research work being carried out at the NED University is to highlight soft soil areas in Sindh and promote the use of Geo-Textiles as reinforcement in Soft Soils. The presentation will focus on flexible pavement Construction method, problem in soft soil construction and methods of stabilization before construction in soft soil.

The soft area is 11.4% of the total land area of Pakistan (90,400 hectsres). According to the data of soft soil, two major highways of Pakistan (N-5 and N-55) traverse through this area, N-5 connects Karachi-Lahore-Peshawar and N-55 (Indus Highway) connects Kotri-Shikarpur-D.G.Khan-D.I.Khan-Kohat-Peshawar.

The National Highway Authority (NHA) has planned to improve and widen the road to international standards i.e, 7.3m carriageway with 1.3 m shoulders on either side. The 61-km long Lakhi-Naudero-Larkana section has recently been finalized for construction.

Condition of the parts of the roads which lie in soft soil areas are investigated and experimental work on Triaxial samples using Triaxial Apparatus is being organized.

Pressure will be applied on samples, with vertical and horizontal stresses acting on the samples will be determined as both woven and nonwovens samples of Geo-Textiles will be part of the experiment. The work in progress is to determine how Geo-Textiles can enhance stability of roads.