Compaction characteristics of soil

Compaction, Its definition, uses, Factors affecting compaction
Field compaction methods and equipments. Solved Numerical and graphical representation of compaction curve and Zero air void line to obtain Optimum moistute content and Maximum dry density.

1. COMPACTION CHARACTERISTICS OF SOIL By, Ms. Shruthi Hiremath M E (Geotechnical Engg .) Assistant Professor Sanjivani College of Engineering Kopargaon

2. COMPACTION OF SOIL The densification of soil by the application of mechanical energy is known as compaction The objectives of compaction are: • To increase soil shear strength and therefore its bearing capacity.   • To reduce subsequent settlement under working loads.   • To reduce soil permeability making it more difficult for water to flow throughly .

3. , COMPARISON BETWEEN COMPACTION AND CONSOLIDATION Compaction Consolidation 1. Compaction is the process by which solid soil particles are packed more closely together by mechanical means. 2. It is achieved through reduction of air voids. 3. It is a rapid process. 4. It is an artificial process. 5. Proper compaction of soil is achieved at optimum moisture content. 1. Consolidation is the process by which soil particles are packed more closely together under the application of static loading 2. It is achieved through gradual drainage of water from soil pores. 3. It is a gradual process. In some soils it takes many years. 4. It is a natural process. 5. Consolidation is strictly applicable for saturated or nearly saturated clays or soils with low permeability.

4. LABORATORY COMPACTION There are several tests with standard procedures such as: • Indian Standard Light Compaction Test (similar to Standard Proctor Test) • Indian Standard Heavy Compaction Test (similar to Modified Proctor Test)

5. DEFINATION OF COMPACTION  2 >  1 1=W1V1 2=W1/V2

6. FACTOR AFFECTING COMPATION WATER CONTENT COMPACTING EFFORT TYPE OF SOIL METHOD OF COMPACTION 1 2 3 4

7. 1. Density - WATER CONTENT relationship

8. 2. COMPACTIVE EFFORT

9. 3. TYPE OF SOIL compactive curve Description of Soil 1 Well graded to loamy sand(SW-SM ) 2 Well graded sandy loam (SM) 3 Med graded sandy loam(SM) 4 Lean sandy silt clay(CL) 5 Lean silty clay(CI) 6 Loessial silt(ML) 7 Heavy clay(CH) 8 poorly graded sand(SP)

10. Compaction curve Method 1 Laboratory static compaction at 13790 kPa 2 Modified AASHTO compaction 3 Standard proctor compaction 4 Laboratory static compaction at 1379kPa 5 Field compaction rubber lyred loaded ,6 passes 6 Field compaction sheep’s foot rollers,6 passes 4. METHOD OF COMPACTION

11. LABORATORY TEST TO DETERMINE SOIL COMPACTION Standard Proctor test (Light compaction Test) IS 2720 Part 7,1970 Modified Proctor Test (heavy compaction Test) IS 2720-part 8, 1983

12. GRAPHICAL REPRESENTATION

13. SOIL COMPACTION IN THE FIELD

14. Proctor Needle

15. 1. In a standard Proctor test following observations were recorded: Plot the moisture density curve and find MDD and OMC and also draw ZAV line. Numerical Sample No. Bulk Density ( Vb ) kg/m3 Water content (w) % 1 1310 16.1 2 1515 19.5 3 1875 27.55 4 1860 33.69 5 1775 34.77

16. Solution… Sample No. Bulk Density (Vb) Water content (w) % Dry density (Vd) Vd = Dry density ( Vd ) at Sr =100% =1 (Assume G=2.7) kg/m3 gm/cc kg/m3 gm/cc kg/m3 gm/cc 1 1310 1.31 16.1 1128 1.128 1882 1.882 2 1515 1.515 19.5 1268 1.268 1768 1.768 3 1875 1.875 27.55 1470 1.470 1548 1.548 4 1860 1.860 33.69 1391 1.391 1413 1.413 5 1775 1.775 34.77 1317 1.317 1392 1.392

17. Compaction curve Maximum Dry Density( Vd ) =1.47gm/cc Optimum moisture content (OMC)% = 27.55%

18. Thank you