Ground improvement using vibro-stone technique
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This document summarizes the vibro-stone column ground improvement technique. It discusses that stone columns involve installing compacted columns of crushed stone in the ground to improve load bearing capacity and reduce settlement. There are two main installation methods - non-displacement using bored and rammed systems, and displacement using vibro-replacement. The design of stone columns considers factors like column diameter, spacing, replacement ratio, loading patterns, site conditions, and installation technique to meet settlement tolerances. Stone columns function to increase bearing capacity, improve stiffness, carry high loads, and homogenize variable soil properties.
Ground improvement using vibro-stone technique
- 1. GROUND IMPROVEMENT USING THE VIBRO-STONE COLUMN TECHNIQUE By Ahmed A. ABDULLAH CE 562 Gaziantep University
- 2. WHAT IS THE REQUIREMENT OF GROUND IMPROVEMENT? Toalter the natural properties of rock or soil Reducing compressibility and permeability Increasing strength ,bearing capacity
- 3. WHY STONE COLUMNS? Offer alternative foundation system to the conventional pile foundation system
- 4. WHAT IS STONE COLUMN? A ground improvement technique to improve the load bearing capacity and reduce the settlement of the soil Stone column consists of crushed coarse aggregates of various sizes
- 5. INFLUENCING FACTORS Soil Treatment depth Area of treatment
- 6. INSTALLATION TECHNIQUES NON DISPLACEMENT METHOD BORED RAMMED SYSTEM DISPLACEMENT METHOD VIBRO REPLACEMENT METHOD
- 7. INSTALLATION PROCEDURE 1. TOP FEED SYSTEM 2. BOTTOM FEED SYSTEM
- 8. TOP FEED SYSTEM Penetration Stone Feeding Compaction Finishing
- 10. BOTTOM FEED SYSTEM Penetration Stone Feeding Compaction Finishing
- 12. DESIGN DESIGN PARAMETERS 1. Stone Column Diameter 2. Pattern Of Arrangement D= stone diameter D
- 13. 3. Spacing 4. Replacement ratio K= π for square grids = 2π/√3 for triangular column grids •LOADING PATTERN •SITE CONDITION •COLUMN FACTORS •INSTALATION TECHNIQUE •SETTLEMENTTOLERANCE
- 15. 6. Stress Concentration factor m=σs/ σg Where, m = Stress concentration factor σs = Average stress in the stone Column σg = The stress in the soilwithin the unit cell The value of m generally lies between 2.5 and 5 at the ground surface 7. Bearing Capacity q = ultimate vertical stress φ'= The friction angle of the stone infill σ'ro =the free-field lateral effective stress cu = is the undrained shear strength Hughes and Witches(1974)
- 16. 8.Aggregate
- 17. FUNCTIONS AND USES 1. To increase the bearing capacity 2. Improves the stiffness of subsoil to decrease settlements 3. To carry very high loads 4. More economical than piling 5. No waiting period after installation 6. homogenizes variable soil properties
- 18. USES
- 19. LIMITATION with sensitivity greater than 4 installed at a distance of less than 3.66m
- 20. CONCLUSION
- 21. THANK YOU