Design of Shallow and Deep Foundations

Cover
Half Title
Title Page
Copyright Page
Table of Contents
Preface
Additional Preface for the English Version
Authors
1 Actions for Limit State Design
	1.1 Definition of actions
		1.1.1 Permanent actions G
		1.1.2 Actions due to groundwater
		1.1.3 Lateral thrusts G[sub(sp)]
		1.1.4 Negative friction G[sub(sn)]
		1.1.5 Variable actions Q
		1.1.6 Accidental actions A
		1.1.7 Seismic actions A [sub(E)]
	1.2 Combinations of actions
		1.2.1 ULSs
			1.2.1.1 Fundamental combinations
			1.2.1.2 Combinations for accidental situations
			1.2.1.3 Combinations for seismic situations
		1.2.2 SLSs
			1.2.2.1 Quasi-permanent combinations
			1.2.2.2 Characteristic combinations
2 Shallow Foundations
	2.1 Definitions
	2.2 Bearing capacity
		2.2.1 From shear strength parameters (“c-φ” method)
			2.2.1.1 Strip footing – vertical and centred load
			2.2.1.2 Influence of the shape of the foundation: vertical and centred load
			2.2.1.3 Influence of load eccentricity and inclination
			2.2.1.4 Foundations on heterogeneous soils
			2.2.1.5 Foundations on a slope or close to the crest of a slope
		2.2.2 Pressuremeter (M)PMT and penetrometer (CPT) methods: definitions
			2.2.2.1 Equivalent embedment height D[sub(e)]
			2.2.2.2 Equivalent net limit pressure ple[sup(*)]with the  Ménard pressuremeter M(PMT)
			2.2.2.3 Equivalent cone resistance q[sub(ce)] with the cone penetrometer (CPT)
		2.2.3 Conventional categories of soils
		2.2.4 Bearing capacity design from the Ménard pressuremeter test ((M)PMT)
			2.2.4.1 Centred vertical load
			2.2.4.2 Influence of eccentricity i[sub(e)]
			2.2.4.3 Influence of load inclination i[sub(δ)]
			2.2.4.4 Influence of the proximity of a slope i[sub(β)]
			2.2.4.5 Combination of i[sub(δ)], i[sub(β)]and i[sub(e)]
		2.2.5 Design of the bearing capacity from the cone penetrometer (CPT)
		2.2.6 Other methods
	2.3 Determining settlement
		2.3.1 Calculation methods of settlement
		2.3.2 Solutions in elasticity
			2.3.2.1 Settlement of an isolated foundation on an elastic semi-infinite medium
			2.3.2.2 Case of a bilayer
			2.3.2.3 Distribution of settlement at surface
			2.3.2.4 Distribution of settlement at depth
			2.3.2.5 Distribution of vertical stress with depth
		2.3.3 Indirect methods: estimating the elasticity moduli
			2.3.3.1 Correlations between the results from in-situ tests and the elasticity modulus
			2.3.3.2 Elasticity modulus variations as a function of deformation and stress levels
		2.3.4 Direct design methods from soil tests
			2.3.4.1 Calculation of settlement from the results of the (M)PMT test
			2.3.4.2 Calculation of settlement from the results of the CPT test
			2.3.4.3 Calculation of settlement from the results of the SPT test
			2.3.4.4 Calculation of settlement from the results of the oedometer test
		2.3.5 Using numerical models
			2.3.5.1 Finite element (or finite difference) method
			2.3.5.2 Hybrid methods
	2.4 Structural design of shallow foundations
	2.5 Verification of a shallow foundation
		2.5.1 Limit states to be considered
		2.5.2 Ground-related limit states
			2.5.2.1 Bearing capacity (ULS and SLS)
			2.5.2.2 Settlement and horizontal displacement (SLS)
			2.5.2.3 Sliding (ULS)
			2.5.2.4 Ground decompression (ULS and SLS)
			2.5.2.5 Overall stability (ULS)
		2.5.3 Limit states related to the materials constituting the foundation
	2.6 Construction provisions
3 Deep Foundations
	3.1 Classification of deep foundations
		3.1.1 Replacement piles
			3.1.1.1 Simple bored pile (and barrette executed in the same conditions)
			3.1.1.2 Pile bored with mud and barrette
			3.1.1.3 Cased bored pile
			3.1.1.4 Piers
			3.1.1.5 Continuous flight auger with simple rotation or double rotation
			3.1.1.6 Micropiles
			3.1.1.7 Injected large-diameter piles, under high pressure
		3.1.2 Displacement piles
			3.1.2.1 Precast piles
			3.1.2.2 Open-ended or closed-ended steel piles
			3.1.2.3 Cast-in-situ driven piles
			3.1.2.4 Cast-in-situ screw piles
			3.1.2.5 Cased screw pile
		3.1.3 Special piles
		3.1.4 Identifying piles by class and category
	3.2 Axially loaded isolated pile
		3.2.1 Definitions
			3.2.1.1 Compressive and tensile resistances
			3.2.1.2 Creep limit load
			3.2.1.3 Equivalent embedment. Equivalent limit pressure and cone resistance
		3.2.2 Conventional rigid-plastic theories
		3.2.3 Predicting the bearing capacity and the creep limit load from a static load test
			3.2.3.1 Principle equipment
			3.2.3.2 Loading programme
			3.2.3.3 Exploiting results
		3.2.4 Design of bearing capacity from the (M)PMT
			3.2.4.1 Calculation of tip resistance R[sub(b)]
			3.2.4.2 Calculation of friction resistance R[sub(s)]
		3.2.5 Bearing capacity design from the CPT
			3.2.5.1 Calculation of tip resistance R[sub(b)]
			3.2.5.2 Design of friction resistance R[sub(s)]
		3.2.6 Using the results of dynamic soil tests
			3.2.6.1 Using results from dynamic penetration
			3.2.6.2 Using penetration tests made with a SPT sampler
		3.2.7 Predicting the bearing capacity from pile driving
			3.2.7.1 Driving tests
			3.2.7.2 Wave propagation analysis
		3.2.8 Settlement of an isolated pile (t-z method)
		3.2.9 Assessing negative friction (downdrag)
			3.2.9.1 Limit unit negative friction q[sub(sn)]
			3.2.9.2 Simplified approach to assess maximum negative friction
			3.2.9.3 Displacement approach (generalised t-z method)
	3.3 Laterally loaded isolated pile
		3.3.1 Conventional rigid-plastic theory
		3.3.2 Subgrade reaction modulus method (p-y method)
			3.3.2.1 Principle. Definitions
			3.3.2.2 Taking into account lateral thrusts
			3.3.2.3 Equilibrium equation
			3.3.2.4 Practical solution
		3.3.3 Selection of the reaction curve
			3.3.3.1 Typical reaction curves
			3.3.3.2 Case of the (M)PMT
			3.3.3.3 Case of the CPT test
			3.3.3.4 Ground shear parameters
			3.3.3.5 Specific case of barrettes
			3.3.3.6 Modifications due to the proximity of a slope or near the surface
		3.3.4 Assessing the free soil displacement g(z)
			3.3.4.1 Definitions
			3.3.4.2 Selection of the dimensionless displacement curve G(Z)
			3.3.4.3 Determining g[sub(max)]. Piles executed  before embankment construction
			3.3.4.4 Determining g[sub(max)]. Piles executed max after embankment construction
		3.3.5 Boundary conditions
			3.3.5.1 Head conditions
			3.3.5.2 Tip conditions
		3.3.6 Lateral load test
	3.4 Behaviour of pile groups
		3.4.1 Axial behaviour
			3.4.1.1 Bearing capacity of a pile group
			3.4.1.2 Tensile resistance of a group of piles
			3.4.1.3 Settlement of a pile group: elastic method
			3.4.1.4 Settlement of a pile group: Terzaghi’s empirical method
			3.4.1.5 Pile group subjected to negative friction (downdrag)
		3.4.2 Lateral behaviour
			3.4.2.1 Empirical methods
			3.4.2.2 Theoretical method (elasticity)
			3.4.2.3 Ground lateral thrusts on a group of piles
		3.4.3 Load distribution on a pile group: simplified cases
			3.4.3.1 Simplifying hypotheses
			3.4.3.2 Case of a two-dimension isostatic foundation
			3.4.3.3 Case of a hyperstatic foundation
		3.4.4 Load distribution on a pile group: use of reaction laws
			3.4.4.1 Principles
			3.4.4.2 Ground reaction laws
			3.4.4.3 Boundary conditions at pile tip and pile head
		3.4.5 Use of numerical models
			3.4.5.1 Finite element (or finite difference) method
			3.4.5.2 Hybrid methods
	3.5 Structural design of deep foundations
		3.5.1 Design bases
		3.5.2 Influence of non-linearities
	3.6 Verification of a deep foundation
		3.6.1 Limit states to be considered
		3.6.2 Ground-related limit states
			3.6.2.1 Bearing capacity and tensile resistance of an isolated deep foundation (ULS and SLS)
			3.6.2.2 Concept of stability diagram under axial loading
			3.6.2.3 Bearing capacity of a pile group (ULS)
			3.6.2.4 Lateral behaviour (ULS and SLS)
			3.6.2.5 Overall stability (ULS)
		3.6.3 Limit states related to the constitutive materials of the foundation (ULS and SLS)
			3.6.3.1 Concrete, grout or mortar of cast-in-situ deep foundations
			3.6.3.2 Concrete, grout or mortar of pre-cast deep foundations
			3.6.3.3 Steel for piles made of reinforced concrete
			3.6.3.4 Steel for other piles
			3.6.3.5 Buckling and second order effects (ULS)
		3.6.4 Displacement (ULS and SLS)
	3.7 Construction provisions and course of action
		3.7.1 Types of piles
		3.7.2 Dimensions. Inclination
			3.7.2.1 Diameter (or width)
			3.7.2.2 Length
			3.7.2.3 Inclination
		3.7.3 Layout of the pile group
		3.7.4 Specific recommendations for cast- in-situ piles and barrettes
		3.7.5 Inspection of cast-in-situ piles and barrettes
		3.7.6 Course of action for a deep foundation study
	Annex 1. Taking into account the effect of negative shaft friction
		A1.1 Isolated pile
		A1.2 Unlimited group of piles
		A1.3 Limited group of piles
	Annex 2. Solutions for the design of laterally loaded piles – Homogeneous and linear ground
		A2.1 Sign convention – general solution
		A2.2 Flexible (or long) pile
			A2.2.1 Solutions for a flexible pile without lateral thrusts (g(z) = 0)
			A2.2.2 Solutions for a flexible pile with lateral thrusts (g(z) ≠ 0)
		A2.3 Rigid (or short) pile
			A2.3.1 Solutions for a short pile without lateral thrusts (g(z) = 0)
			A2.3.2 Solutions for a short pile with lateral thrusts (g(z) ≠ 0)
4 Interactions with the Supported Structure
	4.1 Allowable displacement
		4.1.1 Introduction
		4.1.2 Allowable displacement of foundations of buildings
		4.1.3 Allowable displacement of bridge foundations
	4.2 Soil-structure interactions
		4.2.1 Boundary between “geotechnical” and “structural” models
		4.2.2 Structures on isolated foundations
			4.2.2.1 Notion of stiffness matrix
			4.2.2.2 Stiffness matrix of a shallow footing
			4.2.2.3 Stiffness matrix of a deep foundation
			4.2.2.4 Taking non-linearities into account
		4.2.3 Group effects
		4.2.4 Structures founded on general rafts
Bibliography