The problem
	• Consolidation of soil in soft clayey areas makes things extremely difficult for foundation engineers. • Soft clayey deposits have large voids of space filled with water – termed as pore water. • When loaded, these deposits undergo large scale displacement and have a very low load bearing capacity. • The process of pore water expulsion and reduction in void space is called consolidation.
	The solution
	• Construction of high / heavy embankments directly over clayey / slushy / marshy areas leads to long term settlement • Consolidation takes place rapidly due to radial and vertical movement of pore water. The water then moves flows freely along the drain to the draining blanket placed on the soil surface. • The first draining layer consists of a mixture of crushed stone aggregate 1.5mm – 3mm. • It is then compacted to the desired level. • Over this layer, non-woven coir based geo-tex has to be laid. • The geo-tex material should be double the width of the embankment and laid with equal projections with both the sides – the fold towards the center resulting in the second layer. • Once this is done, 6mm crushed stone aggregate has to be spread and compacted. • The primary solution for construction is the removal of soft soil depending upon the design of the embankment. • next, the embankment materials have to be compacted into thin layers.
	Vertical drains - highlights
	• Installation of vertical drains is one method that reduces consolidation time in clayey soils. • Vertical drains require high permeability and drainage capacity. • Due to excess pore pressure • The projected ends of the geo-tex materials folded towards the center have have a gap in the middle to allow any deformation that may result under heavy loads. • It is important to repeat the layer of crushed stone aggregate above the geo-tex layer and compacted as described, earlier. • The geo-tex layer acts as the separator, filter and reinforcement. It also facilitates drainage. • The construction of the embankment is done progressively after ensuring primary consolidation.