Recommendations on Excavations: EAB

The aim of these recommendations is to harmonize and further develop the methods, according to which excavations are prepared, calculated and carried out. Since 1980, these have been drawn up by the working group "Excavations" at the German Geotechnical Society (Deutsche Gesellschaft fur Geotechnik DGGT) and are similar to a set of standards. They help to simplify analysis of excavation enclosures, to unify load approaches and analysis procedures, to guarantee the stability and serviceability of the excavation structure and its individual components, and to find out an economic design of the excavation structure. For this new edition, all recommendations have been reworked in accordance with EN 1997-1 (Eurocode 7) and DIN 1054-1. In addition, new recommendations on the use of the modulus of subgrade reaction method and the finite element method (FEM), as well as a new chapter on excavations in soft soils, have been added.

Table of Contents:
Members of the Working Group for Excavations. Preface. Notes for the user. 1 General Recommendations. 1.1 Engineering requirements for applying the Recommendations (R l). 1.2 Governing regulations (R 76). 1.3 New safety factor approach (R 77). 1.4 Limit states (R 78). 1.5 Support of retaining walls (R 67). 1.6 Using the EAB in conjunction with Eurocode 7-1 (R 105, draft). 2 Analysis principles. 2.1 Actions (R 24). 2.2 Determination of soil properties (R 2). 2.3 Earth pressure angle (R 89). 2.4 Partial safety factors (R 79). 2.5 General requirements for adopting live loads (R 3). 2.6 Live loads from road and rail traffic (R 55). 2.7 Live loads from site traffic and site operations (R 56). 2.8 Live loads from excavators and lifting equipment (R 57). 3 Magnitude and distribution of earth pressure. 3.1 Magnitude of earth pressure as a function of the selected construction method (R 8). 3.2 Magnitude of active earth pressure without surcharge loads (R 4). 3.3 Distribution of active earth pressure load without surcharges (R 5). 3.4 Magnitude of active earth pressure from live loads (R 6). 3.5 Distribution of active earth pressure from live loads (R 7). 3.6 Superimposing earth pressure components with surcharges (R 71). 3.7 Determination of at-rest earth pressure (R 18). 3.8 Earth pressure in retreating states (R 68). 4 General stipulations for analysis. 4.1 Stability analysis (R 81). 4.2 General information on analysis methods (R 11). 4.3 Determination and analysis of embedment depth (R 80). 4.4 Determination of action effects (R 82). 4.5 Limit load design method (R 27). 4.6 Modulus of subgrade reaction method (R 102). 4.7 Finite-element method (R 103). 4.8 Verification of the vertical component of the mobilised passive earth pressure (R 9). 4.9 Verification of the transmission of vertical forces into the subsurface (R 84). 4.10 Stability analyses for braced excavations in special cases (R 10). 4.11 Verification of serviceability (R 83). 4.12 Allowable simplifications in the STR limit state (R 104, draft). 5 Analysis approaches for soldier pile walls. 5.1 Determination of load models for soldier pile walls (R 12). 5.2 Pressure diagrams for supported soldier pile walls (R 69). 5.3 Passive earth pressure for soldier pile walls with free earth supports (R 14). 5.4 Toe restraint for soldier pile walls (R 25). 5.5 Equilibrium of horizontal forces for soldier pile walls (R 15). 6 Analysis approaches for sheet pile walls and in-situ concrete walls. 6.1 Determination of load models for sheet pile walls and in-situ concrete walls (R 16). 6.2 Pressure diagrams for supported sheet pile walls and in-situ concrete walls (R 70). 6.3 Ground reactions and passive earth pressure for sheet pile walls and in-situ concrete walls (R 19). 6.4 Toe restraint for sheet pile walls and in-situ concrete walls (R 26). 7 Anchored retaining walls. 7.1 Magnitude and distribution of earth pressure for anchored retaining walls (R 42). 7.2 Analysis of force transmission from anchors to the ground (R 43). 7.3 Analysis of stability at low failure plane (R 44). 7.4 Analysis of global stability (R 45). 7.5 Measures to counteract displacements in anchored retaining walls (R 46). 8 Excavations with special ground plans. 8.1 Excavations with circular plan (R 73). 8.2 Excavations with oval plan (R 74). 8.3 Excavations with rectangular plan (R 75) (11/05). 9 Excavations adjacent to structures. 9.1 Engineering measures for excavations adjacent to structures (R 20). 9.2 Analysis of retaining walls with active earth pressure for excavations adjacent to structures (R 21). 9.3 Active earth pressure for large distances to structures (R 28). 9.4 Active earth pressure for small distances to structures (R 29). 9.5 Analysis of retaining walls with increased active earth pressure (R 22). 9.6 Analysis of retaining walls with at-rest earth pressure (R 23). 9.7 Mutual influence of opposing retaining walls for excavations adjacent to structures (R 30). 10 Excavations in water. 10.1 General remarks for excavations in water (R 58). 10.2 Seepage pressure (R 59) (11/05). 10.3 Dewatered excavations (R 60). 10.4 Analysis of hydraulic heave safety (R 61). 10.5 Analysis of buoyancy safety (R 62). 10.6 Stability analysis of retaining walls in water (R 63). 10.7 Design and construction of excavations in water (R 64). 10.8 Water management (R 65). 10.9 Monitoring excavations in water (R 66). 11 Excavations in unstable rock. 11.1 General recommendations for excavations in unstable rock (R 38). 11.2 Magnitude of rock pressure (R 39). 11.3 Distribution of rock pressure (R 40). 11.4 Bearing capacity of rock for support forces at the wall toe (R 41). 12 Excavations in soft soils. 12.1 Scope of Recommendations R 91 to R 101 (R 90). 12.2 Slopes in soft soils (R 91). 12.3 Wall types in soft soils (R 92). 12.4 Construction procedure in soft soils (R 93). 12.5 Shear strength of soft soils (R 94). 12.6 Earth pressure on retaining walls in soft soils (R 95). 12.7 Ground reactions for retaining walls in soft soils (R 96). 12.8 Water pressure in soft soils (R 97). 12.9 Determination of embedment depths and action effects for excavations in soft soils (R 98). 12.10 Further stability analyses for excavations in soft soils (R 99). 12.11 Drainage measures in excavations in soft soils (R 100). 12.12 Serviceability of excavation structures in soft soils (R 101). 13 Verification of bearing capacity of structural elements. 13.1 Material parameters and partial safety factors for structural element resistances (R 88). 13.2 Bearing capacity of soldier pile infilling (R 47). 13.3 Bearing capacity of soldier piles (R 48). 13.4 Bearing capacity of sheet piles (R 49). 13.5 Bearing capacity of in-situ concrete walls (R 50). 13.6 Bearing capacity of waling (R 51). 13.7 Bearing capacity of struts (R 52). 13.8 Bearing capacity of trench sheeting and bracing (R 53). 13.9 Bearing capacity of provisional bridges and excavation covers (R 54). 13.10 External bearing capacity of soldier piles, sheet pile walls and cast in-situ concrete walls (R 85). 13.11 Bearing capacity of tension piles and ground anchors (R 86). 14 Measurements and monitoring of excavation structures. 14.1 Purpose of measurements and monitoring (R 31). 14.2 Preparation, implementation and evaluation of measurements (R 32). 14.3 Measured variables (R 33). 14.4 Measurement methods and measurements systems (R 34). 14.5 Location of measurement points (R 35). 14.6 Measurement times (R 36). 14.7 Transfer and processing of measurement results (R 37). Appendix. A 1: Relative density of cohesionless soils (10/05). A 2: Consistency of cohesive soils (10/05). A 3: Properties of cohesionless soils (10/05). A 4: Soil properties of cohesive soils (10/05). A 5: Guide values for the modulus of subgrade reaction ks,h for wet soils. A 6: Partial safety factors for geotechnical variables. A 7: Material properties and partial safety factors for concrete and reinforced concrete structural elements. A 8: Material properties and partial safety factors for steel structural elements. A 9: Material properties and partial safety factors for wooden structural elements. A 10: Empirical values for skin friction and base resistance of sheet pile walls and soldier piles. Bibliography. Terms and notation. Geometrical variables. Subsoil and soil parameters. Earth pressure and passive earth pressure. Further loads, forces and action effects. Analyses using the partial safety factor approach. Miscellany. Recommendations in numerical order.

About the Author :
Edited by the TC "Excavations" of the German Society for Geotechnics (DGGT).