1 / 23

Atterberg's Limits

Atterberg's Limits. Prof Neelam Belani Assistant Professor Civil Engineering Department IT,NU. Content. Soil Consistency Atterberg Limits Liquid Limit Plastic Limit Shrinkage Limit Plasticity Index Liquidity Index Plasticity Chart. Soil Consistency.

wqualls
Download Presentation

Atterberg's Limits

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Atterberg's Limits Prof Neelam Belani Assistant Professor Civil Engineering Department IT,NU

  2. Content • Soil Consistency • Atterberg Limits • Liquid Limit • Plastic Limit • Shrinkage Limit • Plasticity Index • Liquidity Index • Plasticity Chart

  3. Soil Consistency Soil consistence provides a means of describing the degree and kind of cohesion and adhesion between the soil particles as related to the resistance of the soil to deform or rupture Soil Behave Like: SOILD at very low moisture content LIQUIDat very high moisture content

  4. Soil Consistency - Atterberg Limits Depending on Moisture Content soil can be divided into: • Solid • Semi-Solid • Plastic • Liquid - Shrinkage Limit (SL) LI = 0 Moisture Content (w) Plastic Limit (PL) Liquidity Index (LI) Plasticity Index (PI) = PL - LL Liquid Limit (LL) LI = 1 +

  5. Liquid Limit - Definition Liquid Limit (LL) is defined as the moisture content at which soil begins to behave as a liquid material and begins to flow (Liquid limit of a fine-grained soil gives the moisture content at which the shear strength of the soil is approximately 2.5kN/m2)

  6. Liquid Limit - Measurement First Method Casagrande Apparatus ASTM D-4318

  7. Liquid Limit - Measurement Liquid Limit (LL) at N = 25

  8. Liquid Limit – Flow Index w1=44 w2=39 N1=20 N2=30 Flow Index

  9. Liquid Limit - Measurement Second Method Fall Cone Method BS1377

  10. Liquid Limit - Measurement Liquid Limit (LL) at d = 20 mm

  11. Plastic Limit - Definition The moisture content (%) at which the soil when rolled into threads of 3.2mm (1/8 in) in diameter, will crumble.

  12. Plastic Limit - Measurement First Method ASTM D-4318 PL = w% at d 3.2 mm (1/8 in.)

  13. Plastic Limit - Measurement Second Method Fall Cone Method BS1377 Plastic Limit (PL) at d = 20 mm

  14. Plasticity Index - Definition Plasticity Index is the difference between the liquid limit and plastic limit of a soil. PI = LL – PL

  15. Plasticity Index - Definition PI (%) = 4.12 IF (%) PI (%) = 0.74 IFC (%) Question!! Which PI is more reasonable for construction projects? The high one or the low one?!

  16. Shrinkage Limit - Definition The moisture content, in percent, at which the volume of the soil mass ceases to change

  17. Shrinkage Limit - Definition

  18. Shrinkage Limit - Measurement

  19. Soil Consistency - Atterberg Limits Depending on Moisture Content soil can be divided into: • Solid • Semi-Solid • Plastic • Liquid - Shrinkage Limit (SL) LI = 0 Moisture Content (w) Plastic Limit (PL) Liquidity Index (LI) Plasticity Index (PI) = PL - LL Liquid Limit (LL) LI = 1 +

  20. Liquidity Index - Definition

  21. Plasticity Chart - Definition • Casagrande (1932) studied the relationship of the plasticity index to the liquid limit of a wide variety of natural soils. • He proposed a plasticity chart

  22. Organic Inorganic Silt Clay

More Related