COMPACTION DEWATERING Soil improvement

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COMPACTION DEWATERINGSoil improvement
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• Soil is extensively used as a basic material of
  construction.  For example dams, embankments,
  ramps, etc.  The advantages of using soil are
  that it
• (1) is generally available everywhere,
• (2) is durable - it will last a long time, and
• (3) has a comparatively low cost.

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Why Does It Need Compacted?

• Compaction increases a soils density.  This
  produces the following effects1.  increases the
  soil's shear strength2.  decreases future
  settlement3.  decreases the soil's permeability
  (also a function of soil type)4.  stable against
  volume change as water content or other factors
  change5.  relatively durable and safe against
  deterioration

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Factor for compaction

• Soil Types/ Machine Types
• Compaction energy
• pressure (weight, system)
• speed of rolling
• the number of times
• Optimum water content
• Dewatering

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Types of compactors
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Compaction Control Field Testing

• Sand Cone
• Densometer
• Oil Replacement
• Nuclear Densometer

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Dewatering

• When soil is excavated below or near the water
  table, pumps will usually be used to dewater the
  site.  This involves creating a drawdown curve
  that is below the base of the excavation. 
  Factors that are important include soil
  permeability, depth of water table, depth (and
  geometry) of excavation.

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Drainage sump pump
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Dewatering well
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Settlement and Consolidation of Soils

• Any structure built on soil is subject to
  settlement. Some settlement is inevitable and,
  depending on the situation, some settlements are
  tolerable. When building structures on top of
  soils, one needs to have some knowledge of how
  settlement occurs and predict how much and how
  fast settlement will occur in a given situation.

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Important factors that influence settlement

• Soil Permeability
• Soil Drainage
• Load to be placed on the soil
• History of loads placed upon the soil (normally
  or over-consolidated?)
• Water Table