This practical handbook of properties for soils and rock contains in a concise tabular format the key issues relevant to geotechnical investigations, assessments and designs in common practice. There are brief notes on the application of the tables. These data tables are compiled for experienced geotechnical professionals who require a reference document to access key information. There is an extensive database of correlations for different applications. The book should provide a useful bridge between soil and rock mechanics theory and its application to practical engineering solutions.
The initial chapters deal with the planning of the geotechnical investigation and the classification of the soil and rock properties, after which some of the more used testing is covered. Later chapters show the reliability and correlations that are used to convert that data in the interpretative and assessment phase of the project. The final chapters apply some of these concepts to geotechnical design. The emphasis throughout is on application to practice.
This book is intended primarily for practicing geotechnical engineers working in investigation, assessment and design, but should provide a useful supplement for postgraduate courses. It evolved from the need to have a "go to" reference book which has both breadth and depth of information to apply immediately to projects. To keep to a handbook size one has to compress/restrict details to a few key bullet points - but a comprehensive reference list provides the "appendix" for additional information if required. This 2nd edition keeps to that format but contains updated information and adjustments that take into account feedback received since initial publication.
Burt Look is a practicing consulting geotechnical engineer. He obtained his first degree in Civil Engineering and his Master's degree in Soil Mechanics and Engineering Seismology at the Imperial College of Science and Technology, University of London. He completed his PhD at The University of Queensland.and he is a Fellow of the Institute of Engineers, Australia. He is currently a Geotechnical Practice Leader at Sinclair Knight Merz. He was formerly a Principal and the Geotechnical Knowledge and Service Delivery Leader at Connell Wagner (now Aurecon). His key role is in the planning and assessment of geotechnical investigations and its implementation into the design. He lectures short courses in industry for Education Engineers Australia to practicing professionals. His research is focused on applications in industry practice and he supervises theses at both The University of Queensland and Queensland University of Technology, Australia.
1 Site investigation 1.1 Geotechnical engineer 1.2 Developing models 1.3 Geotechnical involvement 1.4 Geotechnical requirements for the different project phases 1.5 Relevance of scale 1.6 Planning of site investigation 1.7 Planning of groundwater investigation 1.8 Level of investigation 1.9 Planning prior to ground truthing 1.10 Extent of investigation 1.11 Site investigation for driven piles to rock 1.12 Volume sampled 1.13 Relative risk ranking of developments 1.14 Sample amount 1.15 Sample disturbance 1.16 Sample size 1.17 Quality of site investigation 1.18 Costing of investigation 1.19 Site investigation costs 1.20 The business of site investigation 2 Soil classification and description 2.1 Important information 2.2 Soil borehole record 2.3 Borehole record in the field 2.4 Drilling information 2.5 Water level 2.6 Soil type 2.7 Major and minor components of soil descriptions 2.8 Field guide identification 2.9 Sedimentation test 2.10 Unified soil classification 2.11 Particle description 2.12 Gradings 2.13 Colour 2.14 Soil plasticity 2.15 Atterberg limits 2.16 Consistency of cohesive soils 2.17 Consistency of non-cohesive soils 2.18 Structure 2.19 Moisture content 2.20 Origin 2.21 Comparison of characteristics between residual and transported soils 2.22 Classification of residual soils by its primary mode of occurrence 3 Rock classification 3.1 Important rock information 3.2 Rock description 3.3 Field rock core log 3.4 Drilling information 3.5 Rock weathering 3.6 Colour 3.7 Rock structure 3.8 Rock quality designation 3.9 Rock strength 3.10 Rock hardness 3.11 Discontinuity scale effects 3.12 Rock defects spacing 3.13 Rock defects description 3.14 Rock defect symbols 3.15 Sedimentary and pyroclastic rock types 3.16 Metamorphic and igneous rock types 4 Field sampling and testing 4.1 Types of sampling 4.2 Boring types 4.3 Field sampling 4.4 Field testing 4.5 Comparison of in situ tests 4.6 Standard penetration test in soils 4.7 Standard penetration test in rock 4.8 Overburden correction factors to SPT result 4.9 Equipment and borehole correction factors for SPT result 4.10 Cone penetration test 4.11 Dilatometer 4.12 Pressuremeter test 4.13 Vane shear 4.14 Vane shear correction factor 4.15 Dynamic cone penetrometer tests 4.16 Light weight falling deflectometer 4.17 Clegg impact soil tester 4.18 Surface strength from site walk over 4.19 Surface strength from vehicle drive over 4.20 Operation of earth moving plant 5 Soil strength parameters from classification and testing 5.1 Errors in measurement 5.2 Clay strength from pocket penetrometer 5.3 Clay strength from SPT data 5.4 Residual soils strength from SPT data 5.5 Clean sand strength from SPT data 5.6 Fine and coarse sand strength from SPT data 5.7 Effect of aging 5.8 Effect of angularity and grading on strength 5.9 Critical state angles in sands 5.10 Peak and critical state angles in sands 5.11 Strength parameters from DCP data 5.12 CBR value from soil classification test 5.13 CBR value from DCP data 5.14 CBR values from DCP data specific to soil type 5.15 Allowable bearing capacity from DCP tests 5.16 Soil classification from cone penetration tests 5.17 Soil type from friction ratios 5.18 Clay parameters from cone penetration tests 5.19 Clay strength from cone penetration tests 5.20 Simplified sand strength assessment from cone penetration tests 5.21 Soil type from Dilatometer test 5.22 Lateral soil pressure from Dilatometer test 5.23 Soil strength of sand from Dilatometer test 5.24 Clay strength from effective overburden 5.25 Variation of undrained strength ratio 6 Rock strength parameters from classification and testing 6.1 Rock strength 6.2 Typical refusal levels of drilling rig 6.3 Parameters from drilling rig used 6.4 Field evaluation of rock strength 6.5 Rock strength from point load index values 6.6 Strength from Schmidt hammer 6.7 Strength assessment from RQD 6.8 Relative change in strength between rock weathering grades 6.9 Parameters from rock weathering 6.10 Rock classification 6.11 Rock strength from slope stability 6.12 Typical field geologist's rock strength 6.13 Typical engineering geology rock strengths 6.14 Relative strength - combined considerations 6.15 Parameters from rock type 6.16 Rock durability 6.17 Material use 7 Soil properties and state of the soil 7.1 Soil behaviour 7.2 State of the soil 7.3 Soil weight 7.4 Significance of colour 7.5 Plasticity characteristics of common clay minerals 7.6 Weighted plasticity index 7.7 Effect of grading 7.8 Effective friction of granular soils 7.9 Effective strength of cohesive soils 7.10 Over-consolidation ratio 7.11 Pre-consolidation stress from cone penetration testing 7.12 Pre-consolidation stress from Dilatometer 7.13 Pre-consolidation stress from shear wave velocity 7.14 Over-consolidation ratio from Dilatometer 7.15 Lateral soil pressure from Dilatometer test 7.16 Over consolidation ratio from undrained strength ratio and friction angles 7.17 Over-consolidation ratio from undrained strength ratio 7.18 Sign posts along the soil suction pF scale 7.19 Soil suction values for different materials 7.20 Capillary rise 7.21 Equilibrium soil suctions in Australia 7.22 Effect of climate on soil suction change 7.23 Effect of climate on active zones 7.24 Compaction concepts 7.25 Effect of compaction on suction 8 Permeability and its influence 8.1 Typical values of permeability 8.2 Permeability equivalents 8.3 Comparison of permeability with various engineering materials 8.4 Permeability based on grain size 8.5 Permeability based on soil classification 8.6 Permeability from dissipation tests 8.7 Effect of pressure on permeability 8.8 Effect of fines on permeability 8.9 Permeability of compacted clays 8.10 Effect of moulding water content on permeability 8.11 Permeability of untreated and asphalt treated aggregates 8.12 Dewatering methods applicable to various soils 8.13 Radius of influence for drawdown 8.14 Typical hydrological values 8.15 Relationship between coefficients of permeability and consolidation 8.16 Typical values of coefficient of consolidation 8.17 Variation of coefficient of consolidation with liquid limit 8.18 Coefficient of consolidation from dissipation tests 8.19 Time factors for consolidation 8.20 Time required for drainage of deposits 8.21 Estimation of permeability of rock 8.22 Effect of joints on rock permeability 8.23 Lugeon tests in rock 9 Rock properties 9.1 General engineering properties of common rocks 9.2 Rock weight 9.3 Rock minerals 9.4 Silica in igneous rocks 9.5 Hardness scale 9.6 Rock hardness 9.7 Influence of properties on bored pile 9.8 Mudstone-shale classification based on mineral proportion 9.9 Relative change in rock property due to discontinuity 9.10 Rock strength due to failure angle 9.11 Rock defects and rock quality designation 9.12 Rock laboratory to field strength 9.13 Rock shear strength and friction angles of specific materials 9.14 Rock shear strength from RQD values 9.15 Rock shear strength and friction angles based on geologic origin 9.16 Friction angles of rocks joints 9.17 Asperity rock friction angles 9.18 Shear strength of filled joints 10 Material and testing variability with risk assessment 10.1 Variability of materials 10.2 Variability of soils 10.3 Variability of in-situ tests 10.4 Soil variability from laboratory testing 10.5 Guidelines for inherent soil variability 10.6 Compaction testing 10.7 Guidelines for compaction control testing 10.8 Subgrade and road material variability 10.9 Deflection testing for pavements 10.10 Distribution functions 10.11 Distribution functions for rock strength 10.12 Effect of distribution functions on rock strength 10.13 CBR values for a linear (transportation) project 10.14 Point load index values for a vertical linear (bridge) project 10.15 Variability in design and construction process 1 10.16 Prediction variability for experts compared with industry practice 10.17 Variability in selecting design values 10.18 Tolerable risk for new and existing slopes 10.19 Probability of failures of rock slopes 10.20 Qualitative risk analysis 10.21 Qualitative measure of likelihood 10.22 Qualitative measure of consequences to property 10.23 Risk level implications 10.24 Acceptable probability of slope failures 10.25 Probabilities of failure based on lognormal distribution 10.26 Project reliability 10.27 Road reliability values 10.28 Reliability index 10.29 Concrete quality 10.30 Soil property variation for reliability calibration 10.31 Testing, spatial and temporal variation 11 Deformation parameters 11.1 Modulus definitions 11.2 Small strain shear modulus 11.3 Comparison of small to large strain modulus 11.4 Strain levels for various applications 11.5 Modulus applications 11.6 Typical values for elastic parameters 11.7 Elastic parameters of various soils 11.8 Typical values for coefficient of volume compressibility 11.9 Coefficient of volume compressibility derived from SPT 11.10 Deformation parameters from CPT results 11.11 Drained soil modulus from cone penetration tests 11.12 Soil modulus in clays from SPT values 11.13 Drained modulus of clays based on strength and plasticity 11.14 Undrained modulus of clays for varying over consolidation ratios 11.15 Soil modulus from SPT values and plasticity index 11.16 Short and long term modulus 11.17 Poisson ratio in soils 11.18 Resilient modulus 11.19 Typical rock deformation parameters 11.20 Rock deformation parameters 11.21 Rock mass modulus derived from the intact rock modulus 11.22 Modulus ratio based on open and closed joints 11.23 Rock modulus from rock mass ratings 11.24 Poisson ratio in rock 11.25 Significance of modulus 12 Earthworks 12.1 Earthworks issues 12.2 Excavatability 12.3 Excavation requirements 12.4 Excavation characteristics 12.5 Excavatability assessment 12.6 Excavatability assessment for heavy ripping equipment 12.7 Excavatability assessment based on seismic wave velocities 12.8 Excavatability production rates 12.9 Diggability index 12.10 Diggability classification 12.11 Excavations in rock 12.12 Rippability rating chart 12.13 Bulking factors 12.14 Practical maximum layer thickness 12.15 Large compaction equipment 12.16 Ease of compaction 12.17 Compaction requirements for various applications 12.18 Required compaction 12.19 Comparison of relative compaction and relative density 12.20 Field characteristics of materials used in earthworks 12.21 Typical compaction characteristics of materials used in earthworks 12.22 Suitability of compaction plant 12.23 Typical lift thickness 12.24 Maximum size of equipment based on permissible vibration level 12.25 Compaction required for different height of fill 12.26 Typical compaction test results 12.27 Field compaction testing 12.28 Standard versus modified compaction 12.29 Application of standard and modified compaction 12.30 Effect of excess stones 13 Subgrades and pavements 13.1 Types of subgrades 13.2 CBR laboratory model 13.3 CBR tests in subgrade assessment 13.4 CBR reporting 13.5 CBR soaked and unsoaked tests 13.6 Subgrade strength classification 13.7 Damage from volumetrically active clays 13.8 Subgrade volume change classification 13.9 Minimising subgrade volume change 13.10 Subgrade moisture content 13.11 Subgrade strength correction factors to soaked CBR 13.12 Approximate CBR of clay subgrade 13.13 Typical values of subgrade CBR 13.14 Properties of mechanically stable gradings 13.15 Soil stabilisation with additives 13.16 Soil stabilisation with cement 13.17 Effect of cement soil stabilisation 13.18 Soil stabilisation with lime 13.19 Lime stabilisation rules of thumb 13.20 Soil stabilisation with bitumen 13.21 Pavement strength for gravels 13.22 CBR values for pavements 13.23 CBR swell in pavements 13.24 Plasticity index properties of pavement materials 13.25 Typical CBR values of pavement materials 13.26 Typical values of pavement modulus 13.27 Typical values of existing pavement modulus 13.28 Equivalent modulus of sub bases for normal base material 13.29 Equivalent modulus of sub bases for high standard base material 13.30 Typical relationship of modulus with subgrade CBR 13.31 Typical relationship of modulus with base course CBR 13.32 Aggregate loss to weak subgrades 13.33 Elastic modulus of asphalt 13.34 Poisson ratio 13.35 Specific gravity 14 Slopes 14.1 Slope measurement 14.2 Factors causing slope movements 14.3 Causes of slope failure 14.4 Factors of safety for slopes 14.5 Factor of safety for different input assumptions 14.6 Comparison of factor of safety with probability if failure 14.7 Factors of safety for new slopes 14.8 Factors of safety for existing slopes 14.9 Risk to life 14.10 Economic and environmental risk 14.11 Cut slopes 14.12 Fill slopes 14.13 Factors of safety for dam walls 14.14 Typical slopes for low height dam walls 14.15 Effect of height on slopes for low height dam walls 14.16 Design elements of a dam walls 14.17 Stable slopes of levees and canals 14.18 Slopes for revetments 14.19 Crest levels based on revetment type 14.20 Crest levels based on revetment slope 14.21 Stable slopes underwater 14.22 Side slopes for canals in different materials 14.23 Seismic slope stability 14.24 Stable topsoil slopes 14.25 Design of slopes in rock cuttings and embankments 14.26 Factors affecting the stability of rock slopes 14.27 Rock falls 14.28 Coefficient of restitution 14.29 Rock cut stabilization measures 14.30 Rock trap ditch 14.31 Trenching 15 Terrain assessment, drainage and erosion 15.1 Terrain evaluation 15.2 Scale effects in interpretation of aerial photos 15.3 Development grades 15.4 Equivalent gradients for construction equipment 15.5 Development procedures 15.6 Terrain categories 15.7 Landslide classification 15.8 Landslide velocity scales 15.9 Slope erodibility 15.10 Erodibility hierarchy 15.11 Soil erosion 15.12 Soil dispersivity 15.13 Erosion thresholds 15.14 Sediment loss from linear vs. concave slopes 15.15 Typical erosion velocities based on material 15.16 Typical erosion velocities based on depth of flow 15.17 Erosion control 15.18 Benching of slopes 15.19 Subsurface drain designs 15.20 Subsurface drains based on soil types 15.21 Open channel seepages 15.22 Comparison between open channel flows and seepages through soils 15.23 Drainage measures factors of safety 15.24 Aggregate drains 15.25 Aggregate drainage properties 15.26 Discharge capacity of stone filled drains 15.27 Slopes for chimney drains 15.28 Drainage blankets 15.29 Resistance to piping 15.30 Soil filters 15.31 Seepage loss through earth dams 15.32 Clay blanket thicknesses 16 Geosynthetics 16.1 Type of geosynthetics 16.2 Geosynthetic properties 16.3 Geosynthetic functions 16.4 Leakage rates 16.5 Static puncture resistance of geotextiles 16.6 Construction survivability ratings 16.7 Physical property requirements 16.8 Robustness classification using the G- rating 16.9 Geotextile durability for filters, drains and seals 16.10 Geotextile durability for ground conditions and construction equipment 16.11 Geotextile durability for cover material and construction equipment 16.12 Robustness geotextile specifications based on strength class 16.13 Establishing geotextile strength class 16.14 Establishing geotextile strength class adjacent to walls 16.15 Pavement reduction with geotextiles 16.16 Bearing capacity factors using geotextiles 16.17 Geotextiles for separation and reinforcement 16.18 Reinforcement location 16.19 Geotextiles as a soil filter 16.20 Geotextile strength for silt fences 16.21 Typical geotextile strengths 16.22 Geotextile overlap 16.23 Modulus improvements with Geosynthetic inclusions 17 Fill specifications 17.1 Specification development 17.2 Pavement material aggregate quality requirements 17.3 Backfill requirements 17.4 Typical grading of granular drainage material 17.5 Pipe bedding materials 17.6 Compacted earth linings 17.7 Constructing layers on a slope 17.8 Durability of pavements 17.9 Dams specifications 17.10 Frequency of testing 17.11 Rock revetments 17.12 Durability 17.13 Durability of breakwater 17.14 Compaction requirements 17.15 Earthworks control 17.16 Typical compaction requirements 17.17 Typical compacted modulus values 17.18 Compaction layer thickness 17.19 Achievable compaction 17.20 Acceptable levels of ground vibration 18 Rock mass classification systems 18.1 The rock mass rating systems 18.2 Rock Mass Rating System - RMR 18.3 RMR system - strength and RQD 18.4 RMR system - discontinuities 18.5 RMR - groundwater 18.6 RMR - adjustment for discontinuity orientations 18.7 RMR - strength parameters 18.8 RMR - application to tunnels, cuts and foundations 18.9 RMR - excavation and support of tunnels 18.10 Norwegian Q system 18.11 Relative block size 18.12 RQD from volumetric joint count 18.13 Relative frictional strength 18.14 Active stress - relative effects of water, faulting, strength/stress ratio 18.15 Stress reduction factor 18.16 Selecting safety level using the Q system 18.17 Support requirements using the Q system 18.18 Prediction of support requirements using Q values 18.19 Prediction of bolt and concrete support using Q values 18.20 Prediction of velocity using Q values 18.21 Prediction of Lugeon using Q values 18.22 Prediction of advancement of tunnel using Q values 18.23 Relative cost for tunnelling using Q values 18.24 Prediction of cohesive and frictional strength using Q values 18.25 Prediction of strength and material parameters using Q values 18.26 Prediction of deformation and closure using Q values 18.27 Prediction of support pressure and unsupported span using Q values 18.28 Geological strength index - structure description 18.29 Geological strength index - discontinuity description 18.30 Geological strength index - estimating value 18.31 Relationship of rock constant m 18.32 Geological strength index - values of parameter m for a range of rock types 18.33 Mohr-Coulomb strength parameters derived from GSI 19 Earth pressures 19.1 Earth pressures 19.2 Limit state modes 19.3 Earth pressure distributions 19.4 Coefficients of earth pressure at rest 19.5 Variation of at rest earth pressure with OCR 19.6 Variation of at rest earth pressure with OCR using the elastic at rest coefficient 19.7 Movements associated with earth pressures 19.8 Active and passive earth pressures 19.9 Distribution of earth pressure 19.10 Application of at rest and active conditions 19.11 Application of passive pressure 19.12 Use of wall friction 19.13 Values of active earth pressures 19.14 Values of passive earth pressures 19.15 Compaction induced pressures 19.16 Live loads from excavators and lifting equipment 20 Retaining walls 20.1 Wall types 20.2 Gravity walls 20.3 Effect of slope behind walls 20.4 Embedded retaining walls 20.5 Typical pier spacing for embedded retaining walls 20.6 Wall drainage 20.7 Minimum wall embedment depths for reinforced soil structures 20.8 Reinforced soil wall design parameters 20.9 Location of potential failure surfaces for reinforced soil walls 20.10 Sacrificial thickness for metallic reinforcement 20.11 Reinforced slopes factors of safety 20.12 Soil slope facings 20.13 Wall types for cuttings in rock 20.14 Drilled and grouted soil nail designs 20.15 Driven soil nail designs 20.16 Sacrificial thickness for metallic reinforcement 20.17 Design of facing 20.18 Shotcrete thickness for wall facings 20.19 Details of anchored walls and facings 20.20 Anchored wall loads 20.21 Anchor ultimate values for load transfer in soils 20.22 Rock anchor bond stress 20.23 Anchor bond length 21 Soil foundations 21.1 Foundation descriptions 21.2 Techniques for foundation treatment 21.3 Types of foundations 21.4 Strength parameters from soil description 21.5 Bearing capacity 21.6 Bearing capacity factors 21.7 Bearing capacity of cohesive soils 21.8 Bearing capacity of granular soils 21.9 Settlements in granular soils 21.10 Upper limits of settlement in sands 21.11 Factors of safety for shallow foundations 21.12 Factors of safety for driven pile foundations 21.13 Pile characteristics 21.14 Working loads for tubular steel piles 21.15 Working loads for steel H piles 21.16 Load carrying capacity for piles 21.17 Pile shaft capacity 21.18 Pile frictional values from sand 21.19 Earth pressure coefficient after pile installation 21.20 End bearing of piles 21.21 Pile shaft resistance in coarse material based on N-value 21.22 Pile base resistance in coarse material based on N-value 21.23 Design parameters for pipe piles in cohesionless siliceous soils 21.24 Pile interactions 21.25 Influence zone for end bearing piles in sands 21.26 Point of fixity 21.27 Uplift on piles 21.28 Plugging of steel piles 21.29 Time effects on pile capacity 21.30 Piled raft foundations for buildings 21.31 Piled embankments for highways and high speed trains 21.32 Dynamic magnification of loads on piled rafts for highways and high speed trains 21.33 Allowable lateral pile loads 21.34 Load deflection relationship for concrete piles in sands 21.35 Load deflection relationship for concrete piles in clays 21.36 Bending moments for PSC piles in stiff clays 22 Rock foundations 22.1 Rock bearing capacity based on RQD 22.2 Rock parameters from SPT data 22.3 Bearing capacity modes of failure 22.4 Compression capacity of rock for uniaxial failure mode 22.5 Ultimate compression capacity of rock for shallow foundations 22.6 Compression capacity of rock for a shear zone failure mode 22.7 Rock bearing capacity factors 22.8 Compression capacity of rock for splitting failure 22.9 Rock bearing capacity factor for discontinuity spacing 22.10 Compression capacity of rock for flexure and punching failure modes 22.11 Factors of safety for design of deep foundations 22.12 Control factors 22.13 Ultimate compression capacity of rock for driven piles 22.14 Shaft capacity for bored piles 22.15 Shaft resistance roughness 22.16 Shaft resistance based on roughness class 22.17 Design shaft resistance in rock 22.18 End bearing capacity of rock socketed piles 22.19 Load settlement of piles 22.20 Pile refusal 22.21 Limiting penetration rates 22.22 Pile installation 23 Movements 23.1 Types of movements 23.2 Foundation movements 23.3 Immediate to total settlements 23.4 Consolidation settlements 23.5 Typical self-weight settlements 23.6 Limiting movements for structures 23.7 Limiting angular distortion 23.8 Relationship of damage to angular distortion and horizontal strain 23.9 Movements at soil nail walls 23.10 Tolerable strains for reinforced slopes and embankments 23.11 Movements in inclinometers 23.12 Acceptable movement in highway bridges 23.13 Acceptable angular distortion for highway bridges 23.14 Serviceability and ultimate piles design 23.15 Tolerable displacement for slopes and walls 23.16 Observed settlements behind excavations 23.17 Settlements adjacent to open cuts for various support systems 23.18 Tolerable displacement in seismic slope stability analysis 23.19 Seismic performance criteria 23.20 Rock displacement 23.21 Allowable rut depths 23.22 Levels of rutting for various road functions 23.23 Free surface movements for light buildings 23.24 Free surface movements for road pavements 23.25 Allowable strains for roadways 23.26 Limiting strains for mine haul roads 23.27 Tolerable deflection for roads 23.28 Tolerable deflection for roads based on CBR 23.29 Tolerable deflection for proof rolling 23.30 Peak particle velocity 23.31 Vibration from typical construction operations 23.32 Perception levels of vibration 24 Appendix - loading 24.1 Characteristic values of bulk solids 24.2 Surcharge pressures 24.3 Live load on sloping backfill 24.4 Construction loads 24.5 Ground bearing pressure of construction equipment 24.6 Vertical stress changes 25 Appendix - conversions 25.1 Length, area and volume 25.2 Mass, density, force and pressure 25.3 Permeability and consolidation 26 References 26.1 General - most used 26.2 Geotechnical investigations and assessment 26.3 Geotechnical analysis and design Index