The testing of unsaturated soils requires greater care and effort than that of saturated soils. Although unsaturated soil mechanics has been embraced by geotechnical engineering, engineering practice has not yet caught up as the characterization of unsaturated soils is difficult and time-consuming, and made harder still by a lack of standards.
Laboratory Tests for Unsaturated Soils collates test procedures to cover all laboratory tests for characterising unsaturated soils. It covers the background, theory, test procedures, and interpretation of test results. Each test procedure is broken down into simple stages and described in detail. The pitfalls of each test and the interpretation of the test results are explained. Test data and calculation methods are given, along with many numerical examples to illustrate the methods of interpretation and to offer the presentation of typical results.
The book is especially useful for students and researchers who are new to the field and provides a practical handbook for engineering applications.
Author(s): Eng-Choon Leong, Martin Wijaya
Publisher: CRC Press
Year: 2023
Language: English
Pages: 435
City: Boca Raton
Cover
Half Title
Title Page
Copyright Page
Dedication
Table of Contents
Preface
Acknowledgments
Chapter 1: Introduction
1.1 Historical development
1.2 Unsaturated soils
1.2.1 Residual soils
1.2.2 Expansive soils
1.2.3 Loess
1.3 Stresses and stress-state variables
References
Further reading
Chapter 2: Basic definitions, test environment and general apparatuses
2.1 Introduction
2.2 Phase relationships
2.2.1 Porosity
2.2.2 Void ratio
2.2.3 Degree of saturation
2.2.4 Gravimetric water content
2.2.5 Volumetric water content
2.2.6 Soil density
2.2.7 Volume-mass relationships
2.3 Role of air
2.4 Test environment
2.5 General apparatuses
References
Chapter 3: Sampling, storage and sample preparation
3.1 Background
3.2 Related standards
3.3 Sampling category and sample quality
3.3.1 BS EN ISO 22475-1 (2006)
3.3.2 ASTM D4220/D4220M (2014)
3.4 Sampling in unsaturated soil
3.5 Labelling soil samples
3.6 Storage of unsaturated soil samples
3.7 Sample preparations
3.7.1 Undisturbed soil specimen
3.7.1.1 Specimen prepared from undisturbed samples with retaining ring
3.7.1.2 Specimen prepared from undisturbed samples without retaining ring
3.7.2 Specimen prepared from re-constituted soil
3.7.3 Specimen prepared from compacted soil
References
Further Reading
Chapter 4: Grain-size distribution, and specific gravity
4.1 Background
4.2 Related standards
4.3 Soil classification based on grain size
4.4 Curve-fitting, grain-size distribution
4.5 Effect of grain size and packing configuration on the SWCC (contacting spheres model)
4.6 Test methods for determining grain-size distribution
4.6.1 Sample preparations
4.6.2 Preparation of dispersing agent
4.6.3 Wet sieving
4.6.4 Dry sieving
4.6.5 Sedimentation test based on hydrometer
4.7 Test methods for determining specific gravity
4.7.1 Specific gravity test based on small fluid pycnometer
4.7.2 Specific gravity test based on large fluid pycnometer
4.7.3 Specific gravity test based on gas jar method
4.7.4 Specific gravity test based on gas pycnometer method
References
Further Reading
Chapter 5: Atterberg limits and shrinkage test
5.1 Background
5.2 Related standards
5.3 Theory
5.3.1 Fine-grained soil classification
5.3.2 Water in soils
5.3.3 Shrinkage and swelling curves of soils
5.3.4 Classification of soil shrinkage curve
5.3.5 Effect of stress history on soil shrinkage curve
5.4 Test methods
5.4.1 Gravimetric water content test
5.4.2 Specimen preparations for liquid limit and plastic limit tests
5.4.3 Liquid limit
5.4.3.1 Liquid limit based on Casagrande apparatus
5.4.3.2 Liquid limit based on fall cone test
5.4.4 Plastic limit test
5.4.5 Shrinkage limit and shrinkage curve test
5.4.5.1 Volumetric shrinkage
5.4.5.2 Linear shrinkage
References
Further reading
Chapter 6: Compaction
6.1 Background
6.2 Related standards
6.3 Theory
6.4 Test methods
6.4.1 Moist sample preparation
6.4.2 Dry sample preparation
6.4.3 Compaction test procedures
6.4.3.1 Standard and modified compaction test
6.4.3.2 Vibrating compaction test
6.4.3.3 Static compaction test
References
Further Readings
Chapter 7: Suction measurement
7.1 Background
7.2 Matric suction
7.3 Osmotic suction
7.4 Total suction
References
Further Reading
Chapter 8: Matric suction measurement: Direct methods
8.1 Introduction
8.2 Jet-filled or small-tip tensiometer
8.3 High-capacity tensiometer
8.3.1 Introduction
8.3.2 Calibration
8.3.3 Evaporation test
8.3.4 Types of equilibrium between HCT and soil specimens
8.4 Null-type axis translation apparatus
8.4.1 Set-up
8.4.2 Operation
8.5 Hygrometer
8.5.1 Calibration
8.5.2 Test procedures
8.5.3 Precaution
References
Chapter 9: Indirect suction measurement methods
9.1 Introduction
9.2 Related standards
9.3 Filter paper method
9.3.1 Calibration
9.3.2 Test procedures
9.3.3 Calculations
9.3.4 Summary
9.4 Thermal conductivity sensor
9.4.1 Calibration
9.4.2 Test procedures
9.5 Electrical resistance sensors
9.5.1 Calibration
9.5.2 Test procedures
9.6 Capacitance sensor
9.6.1 Calibration
9.6.2 Test procedures
9.7 Electrical conductivity of pore water
9.7.1 Saturated extract
9.7.2 Mechanical squeezing
9.8 Summary
References
Further reading
Chapter 10: Soil-water characteristic curve
10.1 Background
10.2 Related standards
10.3 SWCC convention
10.4 Theory
10.4.1 SWCC equations
10.4.1.1 Empirical equations
10.4.1.2 Physical-based equations
10.4.2 Hysteresis
10.4.3 The effect of dry density on SWCC
10.4.4 Bimodal/multimodal SWCC
10.4.5 Using shrinkage curve as an alternative volume measurement
10.5 Test methods
10.5.1 Specimen preparation
10.5.2 Test procedures
10.5.3 Suction intervals
10.5.4 SWCC test on coarse-grained soils
10.5.5 SWCC test on fine-grained soils
10.5.6 Accuracy
10.6 Estimation of SWCC
10.6.1 Pedo-transfer function
10.6.2 One-point method
References
Further reading
Chapter 11: Permeability: Steady-state methods
11.1 Background
11.2 Related standards
11.3 Theory
11.4 Test method
References
Further Reading
Chapter 12: Permeability: Transient-state methods
12.1 Background
12.2 Related standards
12.3 Instantaneous profile method
12.3.1 Test set-up
12.3.2 Test procedures
12.3.2.1 Sample preparation
12.3.2.2 Soil column preparation
12.3.2.3 Column test
12.3.2.3.1 Infiltration
12.3.2.3.2 Imbibition
12.3.2.3.3 Drainage
12.3.2.3.4 Evaporation
12.3.2.4 Finishing
12.4 Multistep outflow method
12.4.1 Test set-up
12.4.2 Test procedures
12.4.2.1 Sample preparation
12.4.2.2 Preparation of apparatus
12.4.2.3 Permeability test
12.4.2.4 Rigid-wall permeameter
12.4.2.5 Flexible-wall permeameter
12.4.2.6 Finishing
12.5 Calculations and data interpretation
12.5.1 Instantaneous profile method
12.5.2 Multistep outflow method
12.6 Summary
References
Further reading
Chapter 13: Oedometer test
13.1 Background
13.2 Related standards
13.3 Theory
13.3.1 Settlement and heave
13.3.2 Compression, shrinkage and wetting-induced volume change
13.3.3 Saturated compression test
13.3.4 CWC compression test
13.3.5 Wetting-induced swelling/swelling pressure
13.3.6 Wetting-induced collapse
13.3.7 Constant-suction compression test
13.3.8 Configuration of oedometer tests
13.4 Test methods
13.4.1 Saturated oedometer test
13.4.1.1 Specimen preparation stage
13.4.1.2 Inundation stage
13.4.2 Loading/unloading stage
13.4.3 Unsaturated oedometer test
13.4.4 CWC and CWC-P tests
13.4.4.1 CWC loading
13.4.4.2 Wetting under constant net normal stress
13.4.4.3 Wetting under constant volume
13.4.5 Stages in the CWC oedometer test
13.4.5.1 Specimen preparation
13.4.5.2 CWC loading/unloading
13.4.5.3 Wetting under constant net normal stress
13.4.5.4 Wetting under constant volume
13.4.5.5 Saturated loading/unloading stage
13.4.6 CWC and CWC-P oedometer test procedures
13.4.6.1 ASTM D3877-08 for one-dimensional expansion, shrinkage and uplift pressure of soil-lime mixtures
13.4.6.2 ASTM D4546-08 for one-dimensional swell or collapse of cohesive soil
13.4.6.3 ASTM D5333-03 for measurement of collapse potential of soils
13.4.6.4 Wijaya (2017) CWC oedometer test procedure
13.4.7 SC Oedometer test
13.4.7.1 Constant-suction loading/unloading stage
13.4.7.2 Suction decrease (SD) stage
References
Further reading
Chapter 14: Constant rate of strain test
14.1 Background
14.2 Related standard
14.3 Theory
14.3.1 Saturated CRS test ( ASTM D4186/D4186M-12 2012)
14.3.2 Unsaturated CRS test
14.4 Test methods
14.4.1 CRS apparatus calibration stages
14.4.1.1 Calibration for apparatus compressibility
14.4.1.2 Calibration for chamber pressure
14.4.1.3 Calibration for piston uplift
14.4.1.4 Calibration for piston seal dynamic friction
14.4.2 Specimen preparation
14.4.3 Saturated CRS test
14.4.3.1 End calibration and set-up stage
14.4.3.2 Saturation stage
14.4.3.3 Loading stage
14.4.3.4 Unloading stage
14.4.3.5 Constant load stage
14.4.3.6 End-stage
14.4.4 CWC-CRS test
14.4.4.1 Suction initialisation stage
14.4.4.2 Calibration and set-up stage
14.4.4.3 Loading stage
14.4.4.4 Unloading stage
14.4.4.5 Inundation stage
14.4.4.6 End-stage
References
Further Reading
Chapter 15: Triaxial test (volume change)
15.1 Background
15.2 Related standards
15.3 Theory
15.3.1 Stress and strain of soils
15.3.2 Compression curve based on stress and strain invariants
15.4 Triaxial test for saturated and unsaturated soil
15.4.1 Volume measurement for unsaturated triaxial test
15.4.1.1 Volume measurement based on confining cell fluid displacement
15.4.1.2 Volume measurement based on specimen fluid displacement
15.4.1.3 Volume measurement based on the direct measurement of specimen dimension
15.5 Triaxial test calibrations
15.5.1 Load cell uplift correction
15.5.2 Filter-paper correction
15.5.3 Membrane correction
15.5.4 Triaxial test calculation
References
Further reading
Chapter 16: Direct shear test
16.1 Background
16.2 Related standards
16.3 Theory
16.4 Test methods
16.4.1 CWC test
16.4.2 CS test
16.5 Test procedures
16.5.1 CWC test
16.5.2 CS test
16.6 Interpretation of test results
References
Chapter 17: Triaxial test (shear strength)
17.1 Background
17.2 Related standards
17.3 Theory
17.3.1 Mohr-Coulomb (MC) model for saturated and unsaturated soil
17.3.2 Failure envelope of unsaturated soil based on the MC model
17.4 CS triaxial test
17.5 CWC triaxial test
17.6 Test methods
17.6.1 UC test
17.6.2 UU test
17.6.3 CU test
17.6.4 CD test
17.6.5 IC test
17.6.6 At rest ( k 0) consolidation test ( k 0 C)
17.6.7 CCSS test
17.6.8 ICSC test
17.6.9 CCWCS test
17.6.10 Isotropic constant water content consolidation test (ICWCC)
References
Further reading
Chapter 18: Ring shear test
18.1 Background
18.2 Related standards
18.3 Test methods and apparatus
18.4 Test procedures
18.5 Calculations
18.6 Summary
References
Chapter 19: Tension test
19.1 Background
19.2 Related standards
19.3 Direct tensile test
19.3.1 Test apparatus
19.3.2 Preparation of soil specimen
19.3.3 Test procedures
19.3.4 Calculations
19.4 Indirect tensile tests
19.4.1 Unconfined penetration test
19.4.1.1 Test apparatus and soil specimen
19.4.1.2 Test procedures
19.4.1.3 Calculations
19.4.2 Brazilian tensile strength test
19.4.2.1 Test apparatus and preparation of soil specimen
19.4.2.2 Test procedures
19.4.2.3 Calculations
19.5 Summary
References
Chapter 20: Wave velocities
20.1 Background
20.2 Related standards
20.3 Bender element test
20.3.1 Test set-up
20.3.2 Test procedures
20.3.3 Interpretations
20.4 Ultrasonic test
20.4.1 Test set-up
20.4.2 Test procedures
20.4.3 Calculations
References
Further reading
Chapter 21: Thermal conductivity
21.1 Background
21.2 Relevant standards
21.3 Theory
21.4 Test method
21.5 Test procedures
21.5.1 Calibration
21.5.2 Soil specimen
21.5.3 Test procedures
21.5.4 Calculations
References
Further reading
Appendix A: Glossary of terms
Appendix B: Formulas and conversion factors
Formulas
Relative humidity, Rh
Total suction, π
Conversion Factors
References
Index
