1. UNIQUE SOILS (BASIC PRINCIPLE & IMPROVEMENT METHOD) Session 11 Course: S0892 - Ground Improvement Method Year: 2010

2. Bina Nusantara COURSE 4 Content: Expansive Soils Organic Soil, Peat Collapsible Soil

3. Bina Nusantara EXPANSIVE SOILS expansive soils are types of soil that shrink or swell as the moisture content decreases or increases. These soils typically contain clay minerals that attract and absorb water.

4. Bina Nusantara EXPANSIVE SOILS – PROBLEMS

5. Bina Nusantara EXPANSIVE SOILS – SOLUTION Static/Mechanical Stabilization –Maintain the water level elevation –Applying load on top to retain the swelling pressure of expansive soils Chemical Stabilization Mixing chemical admixture such as: –Cement –Lime

6. Bina Nusantara EXPANSIVE SOILS – SOLUTIONS

7. Bina Nusantara EXPANSIVE SOILS – SOLUTIONS

8. Bina Nusantara EXPANSIVE SOILS – SOLUTIONS An alternative method for handling highly expansive soils using mass grading is to cover them with 15 feet of select non-expansive fill

9. Bina Nusantara Drilled piers and grade beam foundation systems must extend below the zone of seasonal moisture fluctuation, holding the structure down, when lightly loaded elements are subjected to moisture absorption and heave EXPANSIVE SOILS – SOLUTIONS DRILLED PIERS AND GRADE BEAM

10. Bina Nusantara EXPANSIVE SOILS – SOLUTIONS

11. Bina Nusantara EXPANSIVE SOILS – SOLUTIONS

12. Bina Nusantara EXPANSIVE SOILS – SOLUTIONS

13. Bina Nusantara ORGANIC SOILS (PEAT) Peat is an organic soil which consists more than 70% of organic matters. Peat deposits are found where conditions are favorable for their formation. Peat poses serious problems in construction due to its long-term consolidation settlements even when subjected to a moderate load. Peat is considered unsuitable for supporting foundations in its natural state.

14. Bina Nusantara ORGANIC SOILS (PEAT)

15. Bina Nusantara ORGANIC SOILS (PEAT) – PROBLEMS

16. Bina Nusantara ORGANIC SOILS (PEAT) – SOLUTION The modification of soil properties to improved states of load-bearing capacity may be done in a number of ways including the following (Bowels, 1988): Compaction. Usually the most economical method. Preloading. Primarily to reduce future settlement but may also be used to increase shear strength. Drainage. Used to speed up settlement under preloading but may also increase shear strength. Densification using vibratory equipment. Particularly in silty sand and gravelly sand with a relative density below 50 to 60%. Grouting. Both to reduce voids and to stiffen soil. Chemical stabilization. To stiffen soil. Use of geotextiles. Primarily as reinforcement but sometimes in other beneficial modes.

17. Bina Nusantara ORGANIC SOILS (PEAT) – SOLUTION

18. Bina Nusantara ORGANIC SOILS (PEAT) – SOLUTION

19. Bina Nusantara ORGANIC SOILS (PEAT) – SOLUTION

20. Bina Nusantara COLLAPSIBLE SOILs Soils which are subjected to compressive deformation due to wetting (saturation collapse) under natural conditions Collapsible soils will settle without any additional applied pressure when sufficient water becomes available to the soil. Water weakens or destroys bonding material between particles that can severely reduce the bearing capacity of the original soil. The collapse potential of these soils must bedetermined for consideration in the foundation design.

21. Bina Nusantara COLLAPSIBLE SOILS

22. Bina Nusantara COLLAPSIBLE SOIL – SOLUTION REINFORCEMENT USING GEOSYNTHETIC

23. Bina Nusantara COLLAPSIBLE SOIL – SOLUTION