1. Faculty of Applied Engineering and Urban Planning Civil Engineering Department Soil Mechanics ECGD3303 Atterberg's Limits Lecture 4 Week 2 1 st Quadester 2007/2008 UP Copyrights 2007

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

4. 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 LIQUID at very high moisture content

5. Soil Consistency - Atterberg Limits Depending on Moisture Content soil can be divided into: 1.Solid 2.Semi-Solid 3.Plastic 4.Liquid Shrinkage Limit (SL) Plastic Limit (PL) Liquid Limit (LL) Plasticity Index (PI) = PL - LL Moisture Content (w) + - Liquidity Index (LI) LI = 0 LI = 1

6. Questions?! 20:00 min

7. 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/m 2 )

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

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

10. Liquid Limit – Flow Index Flow Index N 2 =30N 1 =20 w 1 =44 w 2 =39

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

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

13. Questions?! 45:00 min

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

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

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

17. Questions?! 75:00 min

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

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

20. Questions?! 90:00 min

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

22. Shrinkage Limit - Definition

23. Shrinkage Limit - Measurement

24. Questions?! 90:00 min

25. Soil Consistency - Atterberg Limits Depending on Moisture Content soil can be divided into: 1.Solid 2.Semi-Solid 3.Plastic 4.Liquid Shrinkage Limit (SL) Plastic Limit (PL) Liquid Limit (LL) Plasticity Index (PI) = PL - LL Moisture Content (w) + - Liquidity Index (LI) LI = 0 LI = 1

26. Liquidity Index - Definition

27. 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

28. Organic Inorganic Silt Clay

29. Questions?! 120:00 min