Ground improvement is making positive changes to the naturalproperties of a soil by means treatment or addition of other materials. Themain purpose of ground improvement work is to increase the capability of thesoil to retain the load exerted on it by the any structure. There are a fewground improvement methods including deep compaction, vibration columns,vibro-replacement and geotextile sand piles.
Soil compaction is a mechanicalprocess of increasing the density of the soil by applying stress onto theground. The process of soil compaction will reduce the void ratio of the soil,thus make it more compacted. More compacted soil will have higher strengthcompared to the less compacted soil. Embankment is a thick wall of earth usually used to hold water orto uprise the base of any construction projects such as roads and railways.Embankment consist of a few compacted layers until it reaches the requiredheight and strength. Embankment are constructed mostly with soil, but alsoincluding any other possible materials that meet the allowable specificationand quality requirement such as aggregates and rocks. There are a few steps need to be done during the construction workof embankment.
First of all, the embankment site should be cleared so that anyunwanted materials will not affect the layer of embankment. If embankment isbuilt on an existing road, the existingroad must first removed. After all the unwanted materials and debris arecleared from the embankment site, the embankment material are placed. Theembankment materials need to be compacted to a certain specifications. There are some equipment that can be used to do the compaction inthe work field such as vibratory rollers, sheepsfoot rollers and smooth wheelrollers. But not all equipment can be used for all soil type. For example,vibratory rollers are generally used in more silty soils while sheepsfoot areused for clayey and plastic soils. After all the compaction works are done, the soil needs to beevaluated whether it already achieves the requirement or not.
Some tests areconducted to know the characteristic of newly compacted soil. Density and watercontent are usually the most common aspects that are evaluated on the soil atthe work field. Both specifications cab be tested by conducting laboratorytest. Embankment will achieve higher strength at maximum density and maximumdensity can be obtained when the soil has achieved optimum water content. Onethe embankment is finished, a process called proof rolling need to be done toindicate the uniformity of the supporting ability of the embankment.