Compaction & Consolidation

1. Compaction & Consolidation Prof. Mayur M. Maske HoD Civil Engineering(Diploma) RIT, Rajaramnagar Mayur M Maske

2. What is compaction? A simple ground improvement technique, where the soil is densified through external compactive effort. Compactiveeffort + water = Mayur M Maske

3. Definition: Soil compaction is defined as the method of mechanically increasing the density of soil by reducing volume of air. gsoil (2)> gsoil (1) Load Air Air Water Water Soil Matrix Compressed soil Solids Solids WT1 WT1 gsoil (1)= gsoil (2)= VT1 VT2 Mayur M Maske

4. Compaction Mayur M Maske

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8. Compaction- Objectives • Decrease future settlements • Increase shear strength • Decrease permeability • Increases load-bearing capacity • Prevent frost damage • Provides stability • Reduces swelling and contraction Mayur M Maske

9. Factor Affecting Soil Compaction: 1- Soil Type 2- Water Content (wc) 3- Compaction Effort Required (Energy) 4- Compaction method Mayur M Maske

10. Standard Proctor Test Mayur M Maske

11. Laboratory Compaction The fundamentals of compaction of fine-grained soils are relatively new. R.R. Proctor in the early 1930’s was building dams for the old Bureau of Waterworks and Supply in Los Angeles, and he developed the principles of compaction in a series of articles in Engineering News-Record. In his honor, the standard laboratory compaction test which he developed is commonly called the proctor test. Mayur M Maske

12. Laboratory Compaction Purpose The purpose of a laboratory compaction test is to determine the proper amount of mixing waterto use when compacting the soil in the field and the resulting degree of densenesswhich can be expected from compaction at this optimum water. Mayur M Maske

13. 3.1.2 Test Equipment Standard Proctor test equipment Mayur M Maske Das, 1998

14. Modified Proctor Test Soil Compaction in the Lab: 1- Standard Proctor Test 2- Modified Proctor Test Standard Proctor Test Mayur M Maske

15. Number of blows per layer Height of drop of hammer Weight of hammer    Number of layers E = Volume of mold 3.2 Variables of Compaction • Proctor established that compaction is a function of four variables: • Dry density (d) or dry unit weight d. • Water content w • Compactive effort (energy E) • Soil type (gradation, presence of clay minerals, etc.) For standard Proctor test Mayur M Maske

16. 3.3 Procedures and Results (Cont.) Line of optimums Zero air void d max Dry density d (Mg/m3) Dry density d (lb/ft3) Modified Proctor Standard Proctor Water content w (%) Mayur M Maske Holtz and Kovacs, 1981

17. Effect of Energy on Soil Compaction Increasing compaction energy Lower OWC and higher dry density Higher Energy Dry Density In the field increasing compaction energy = increasing number of passes or reducing lift depth ZAV In the lab increasing compaction energy = increasing number of blows Water Content Mayur M Maske

18. General Compaction Methods Coarse-grained soils Fine-grained soils • Falling weight and hammers • Kneading compactors • Static loading and press • Vibrating hammer (BS) Laboratory • Hand-operated vibration plates • Motorized vibratory rollers • Rubber-tired equipment • Free-falling weight; dynamic compaction (low frequency vibration, 4~10 Hz) • Hand-operated tampers • Sheepsfoot rollers • Rubber-tired rollers Field Vibration Kneading Mayur M Maske (Holtz and Kovacs, 1981; Head, 1992)

19. Soil Compaction in the Field: 1- Rammers 2- Vibratory Plates  Mayur M Maske

20. Soil Compaction in the Field: 3- Smooth Rollers 4- Rubber-Tire Mayur M Maske

21. 5- Sheep foot Roller Mayur M Maske

22. 6- Dynamic Compaction Mayur M Maske

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