Geotechnical Engineering examples and solutions using the cavity expanding theory
(pressuremeters, piles, grouted soil anchors)
Dr. József Mecsi
Content
PREFACE
ACKNOWLEDGEMENTS
INTRODUCTION
INTRODUCTION FOR THE PRESENTED MODEL
An overview of the subject on the international scene
A GENERAL OVERVIEW OF THEORETICAL INVESTIGATIONS
Examination of stress and strain in a cylindrical cavity expanded in
a soil half space based on references
Problems of theoretical investigations (as mentioned in specialised literature)
DEFINITIONS OF SOME BASIC TERMS
Stress in soils, density, unit weight of the material, void ratio,
strength and stiffness, volumetric strain
Deformation and strain
Principal stresses in the soil, effective and neutral stresses
Mohr's circle diagram, Coulomb's "fracture-plasticity" or "failure" criteria
Soil stiffness, consolidation
THE SUGGESTED CAVITY EXPANDING THEORY
Basic assumptions
Distinctive characteristics of the model
Application of the Mohr-Coulomb condition
Force equilibriums
Introduction of the non-linear deformability of the soil
Overview of the principal considerations
Relationship between stresses and deformations in the surroundings of an expanded body in the soil
The stress-strain relationship and the deformation modulus of the soil in compaction or expansion
Consideration of the soil volume change
Conditions applied for the model
Determination of the soil pressures at the boundary of the compacted zone (r=ρ)
(Horizontally expanding the vertical cylinder)
Determination of the summarized soil compaction
Examination of the expansion of shrinkage and re-expansion of the process
CYLINDRICAL CAVITY EXPANSION
How does change the stress-strain condition by different radii of the cylinder?
Infinite length vs. finite length problem
EXAMPLES
Example 2.
Example 3.
THE PRESSUREMETER TESTS
Definitions
Basic types of pressuremeter testing
Predrilled pressuremeter tests
Self-boring pressuremeter tests (SBP)
The development of the pressuremeter
Pressuremeter requirements
The tubing system between the probe and the control panel
Requirements
Calibrations
Pressure loss test (P)
Performing a pressuremeter test
Traditional calculations
Calculation of the bearing resistance and se lements
Determination of the soil physical parameters from the pressuremeter curve
Estimation of the soil strength and deformation parameters from the pressuremeter tests
Example 4.
PILE FOUNDATIONS
About piles
Generalities
Classification of piles
Calculating the load bearing capacity of piles
Se lement of single piles
Basic relationships of the cavity expansion, theory for the piles
Determination of the bo om resistance of a pile
Determination of the ultimate bo om resistance of the pile
Example – Determination of the pile bo om resistance
Example 5.
The ultimate shaft resistance of the pile
Mobilised of the shaft resistance of the pile
Case A: The relative displacement between the pile and the surrounding soil is smaller than
the displacement necessary for the mobilization of shear strength.
Case B:The relative displacement between the pile and the surrounding soil is bigger than
the displacement necessary for the mobilization of shear strength.
Determination of the shaft resistance of pile (example)
Example 6.
Examples
Example 7.
Example No 7b.
Example No 8.
Example No 8b. – Determination of the shaft resistance
GROUND ANCHORAGES
Definitions
Design of Anchors
Theoretical Principles
The initial stress state
Stress state due to injection
Specific pull-out resistance
Determination of the force-elongation diagram of an anchor
Anchor force distribution
Analysis of anchor elongation
Determination of the minimal anchor length
LIST OF SYMBOLS
REFERENCES
APPENDIX
József MECSI
CONTENT
