Compactionfield method and interpretation of lab method

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Compactionfield method and interpretation of lab method

  1. 1. What is compaction?  A simple ground improvement technique, where the soil is densified through external compactive effort. COMPACTIONCompactive effort + water =
  2. 2.  There are three method in field compaction Rolling Ramming Vibration
  3. 3.  Rolling - a heavy cylinder is rolled over the surface of the soil. Commonly used on sports pitches. Roller-compactors are often fitted with vibratory devices to enhance their ability. Different types of rollers are used for Compaction. which are depend on following factors Contact pressure Number of passes(normally 5 to 15) Layer thickness (less than 15 cm) Speed of roller
  4. 4.  A hand operated rammer consist of a block of iron,about 3 to 5 kg in mass,attached to a wooden rod.the rammer is lifted for about 0.30 m and dropped on the soil to be compacted A mechanical rammer is operated by compressed air or gasoline power.it is much heavier about 30 to 150 kg. mechanical rammers have been used up to a mass of 1000 kg in some special cases. Tampers are used to compact soil adjecent to existing structures or confined area as trenches,within plinth of building.
  5. 5.  Vibration are induced in the soil during compaction.the compactors are available in a variety of forms.when the vibrator is mounted on adrum,it is called a vibratory roller. these rollers are available both as pneumatic type and the smooth wheel type.in a smooth wheel type, a separate motor drives an arrangement of eccentric weights to create high frequency,low-amplitude,up and down osicillations of the drum. These rollers are suitable for compacting granular soils. Another form of vibratory compactor is a vibrating plate compactor. hand operated vibrating plates are also available.
  6. 6. Instrument of Filed Compaction  Different types of rollers (clockwise from right):  Vibratory rollerPneumatic rubber tired roller  Smooth-wheel roller  Sheepsfoot roller
  7. 7. Smooth Wheeled Roller Compacts effectively only to 200-300 mm; therefore, place the soil in shallow layers (lifts)
  8. 8. Vibrating Plates for compacting very small areas effective for granular soils
  9. 9. Sheepsfoot Roller Provides kneading action; “walks out” after compaction Very effective on clays
  10. 10. Impact Roller Provides deeper (2-3m) compaction. e.g., air field
  11. 11. Laboratory Compaction Test- to obtain the compaction curve and definethe optimum water content and maximumdry density for a specific compactive effort. hammer Modified ProctorStandard Proctor •5 layers•3 layers • 25 blows per• 25 blows per layer layer •4.9 kg hammer•2.7 kg hammer • 450 mm drop• 300 mm drop 1000 ml compaction mould

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