1. GEOTECHNICAL ENGINEERING ECG 503 LECTURE NOTE 12 TOPIC : 4
GEOTECHNICAL ENGINEERING ECG 503 LECTURE NOTE 12 TOPIC : 4.0 GROUND IMPROVEMENT TECHNIQUES OCTOBER 2008

2. LEARNING OUTCOMES Learning outcomes:
At the end of this lecture/week the students would be able to:
Understand natural slope and made engineered soil slope assessment which include rainfall induced failure and role of suction.

3. Hydraulic Methods and Objective of Vertical Drain and Preloading
TOPIC TO BE COVERED
Mechanical Methods and Objective; Stone Column, Dynamic Compaction, Vibrofloatation and Vibro Compaction.
Physical and Chemical Methods and objective; Grouting and cement column
Hydraulic Methods and Objective of Vertical Drain and Preloading

4. Vibroflotation Suitable for granular soils Practiced in several forms:
vibro–compaction
stone columns
vibro-replacement
Vibroflot (vibrating unit) Length = 2 – 3 m Diameter = 0.3 – 0.5 m Mass = 2 tonnes
(lowered into the ground and vibrated)

5. Vibroflotation

6. Vibroflotation

12. GENERAL BACKGROUND OF SOFT CLAY
Malaysia Coastal Area – Not fully developed
Soft clay usually located around the coastal area

13. The soft clay have been a source of difficulties for many years
The soft clay have been a source of difficulties for many years. The soft soil can cause settlement which can give a lot of problem and damage in several way. This is the reason why Malaysia’s coastal areas are not generally developed

14. TWO DISTINCT ATOMIC STRUCTURAL UNITS
0.29 nm
aluminium or magnesium
hydroxyl or oxygen
oxygen
silicon
0.26 nm
Silicon Tetrahedron
Aluminium Octahedron

15. Micro-fabric particles in natural clay.
Dispersed
Flocculated

16. Flaky shape
Plate like structure

17. ION EXCHANGE

18. Ground Improvements for Soft Clay
Stone Column (Vibro-Replacement)
Prefabricated Vertical Drain
Cement Column

19. VIBRO-REPLACEMENT (STONE COLUMN)

21. Vibro-Replacement
Also known as stone column. The technique are similar to vibroflotation/vibrocompaction except the granular fill materials which used is sand is replaced by gravel stone sizes ranging from 50mm to 100mm

22. Soil Layer
Increase in density
Increase in bearing capacity
Radial drainage (help to improve settlement)
Shear strength of soil improve
Reinforcing the soil by applying rigid member (stone column) inside the soil

24. Stone Columns vibrator makes a hole in the weak ground hole backfilled
..and compacted
Densely compacted stone column

27. PREFABRICATED VERTICAL DRAIN (PVD)

33. CEMENT COLUMN (CHEMICAL STABILIZATION)

35. APPLICATION OF STABILIZE CLAY

49. GROUTING TECHNIQUE

59. EXAMPLE OF CASE STUDY FOR GROUND IMPROVEMENT METHODS ON SOFT CLAY