Table of contents
Preface
1 Introduction
1.1 Definition of quality assurance
1.2 Definition of specialised deep foundation engineering
1.3 Quality assurance in specialised deep foundation engineering
2 Diaphragm wall technique
2.1 History of the diaphragm wall technique
2.2 Areas of application
2.3 Notable example of a specialised deep foundation engineering project with diaphragm walls
2.4 Diaphragm wall construction methods
2.4.1 Two-phase construction method
2.4.2 Single-phase construction method
2.4.3 Combined construction method
2.4.4 Deep foundations with diaphragm wall elements
2.5 Description of the construction phases
2.5.1 Preliminary work
2.5.2 Construction of the guide wall
2.5.3 Dividing the wall into panels
2.5.4 Example of the dimensioning of a guide wall
2.6 Excavation
2.6.1 Grab method
2.6.2 Cutter method
2.6.3 Selection of excavation equipment
2.6.4 Special considerations during excavation
2.7 Quality assurance measures for diaphragm wall excavation
2.7.1 Monitoring the slurry level
2.7.2 Verifying the excavation depth
2.7.3 Verifying the verticality of a trench excavation
3 Supporting slurries and their properties
3.1 Density and unit weight of the slurry
3.2 Viscosity, yield strength, and thixotropy of the slurry
3.3 Model for describing slurry properties
3.4 Determining the yield strength
3.5 Additional slurry tests
3.6 Requirements for supporting slurries and clays
3.7 Designation of slurries
3.8 Testing the clay after delivery
3.9 Slurry testing (frequency and timing)
3.10 Permissible values for slurry properties
3.11 Corrective measures for improving slurry properties
3.12 Negative influences on slurry properties
4 Preparing the supporting slurry
4.1 Small mixing units
4.2 Larger mixing units
4.3 Supraton system
4.4 Regeneration units
4.5 Problems when mixing and storing supporting slurry
5 Joints and stop-end elements
5.1 Stop-end tubes
5.2 Flat joint elements
5.3 Pre-cast stop-end elements
5.4 Some special measures to improve the watertightness of joints
6 Analyses for the open trench
6.1 Stability in relation to groundwater ingress
6.2 Safety in relation to the slurry level falling below the minimum level required for structural stability
6.3 Internal trench stability analysis (sloughing and peel-off)
6.4 Gross (external) stability analysis
7 Reinforcement in diaphragm walls
7.1 Formation of reinforcement cages and recesses
7.2 Slab connections
8 Concrete pouring for a diaphragm wall element
8.1 Possible concreting defects
8.2 Remedial work on joint defects
8.3 Remedial work on diaphragm wall surfaces during pit excavation
8.4 Smooth surfaces and prevention of overbreak concrete
9 Precast diaphragm walls
10 Deformation of diaphragm walls
10.1 Measurements on diaphragm walls
10.2 Notes on the installation of measuring equipment
10.3 Deformation forecasting in deep excavations
10.4 Influences on settlement of nearby buildings
10.5 Consideration of installation effects
11 Slurry trench cut-off walls
11.1 Slurry trench cut-off wall method
11.2 Quality assurance in cut-off walls
11.3 Narrow cut-off walls
11.4 Qualification testing of cut-off wall materials
11.5 Determining the cutting resistance of
11.6 Experience with the effects of contaminants on cut-off wall materials
References
