Applied Geotechnics for Construction Projects, Volume 3

Ammar Dhouib, doctor of civil engineering specializing in soil mechanics, is a lecturer and professor of geotechnics at Polytech Sorbonne University, Paris, France. He is also a geotechnical expert at the VINCI construction group and a justice expert at the Court of Appeal in Versailles. His research interests focus on geotechnics, and he has authored or co authored five books on this topic.

• Foreword ixPhilippe GUILLERMAIN† and François SCHLOSSEREntrepreneur’s Tribune: Geotechnics is at the Heart of Our Projects xi Pascal LEMOINE and Eric DURANDPreface xiiiAcknowledgments xixSymbols and Notations xxiIntroduction lvChapter 1 Foundations: Behavior, Design, and Justification 11.1 Analogies and differences between foundations 11.1.1 Foundations and their integration into the geotechnical project 11.1.2 Method of operation and similarities in behavior 31.1.3 Photos providing demonstrations of foundations 61.2 Shallow foundations 71.2.1 Types of shallow foundations 71.2.2 Behavior of a load-bearing footing 91.2.3 Load-bearing capacity of the subsoil 101.2.4 The special case of a footing under an eccentric load 221.2.5 Special cases of footings under an inclined load on horizontal ground 251.2.6 The special case of a footing on the crest of a slope 261.2.7 The case of a footing on two layers 291.2.8 The case of a footing on a dual layer: soft soil on top of a nearby substratum 301.2.9 Calculation of settlements under footings 311.2.10 Special cases: constructive provisions 381.3 Superficial foundations on rafts 401.3.1 Roles and types of rafts 401.3.2 Load-bearing capacity of soil under rafts 411.3.3 Settlements under rafts 411.4 Deep foundations 431.4.1 Preamble 431.4.2 Insulated pile under axial load 441.4.3 Isolated pile under lateral reactions 711.4.4 Effect of groups of piles 811.4.5 Justification of deep foundations 861.5 For the special case of foundation blocks subjected to reverse forces 931.5.1 The elastic center method 941.5.2 The rotation method 951.5.3 Simplified method 961.5.4 The “State Network” method 981.6 Consideration for other forces on the foundations 981.6.1 Spurious stresses due to soil swelling 981.6.2 Parasitic stress due to soil shrinkage 1001.6.3 Seismic actions on piles: simplified Souloumiac method 1001.6.4 The special case of vibrating machines on a non-deformable foundation block 1021.7 Threshold displacements of the structure 1031.7.1 Absolute settlements 1031.7.2 Differential settlements (relative settlements) 104Chapter 2 Real Projects and Comparisons of Methods and Referentials 1092.1 Study of an apartment building on shallow footings 1092.1.1 Project criteria 1092.1.2 Soil data and foundation solution 1102.1.3 Justification of the footings using the pressuremeter method 1122.1.4 Justifications of the footings under the “Eurocodes” using the pressuremeter test (MPT) 1132.1.5 Estimation of settlements (Ménard’s rule T0) 1192.1.6 Comparison of calculation methods in terms of stresses 1202.1.7 Impact of footing dimensions 1292.1.8 Comparison of methods in terms of settlements 1332.1.9 Determining the footing reaction coefficients 1392.1.10 Footing stiffness 1412.1.11 Practical rules for calculating the stiffness of footings 1482.1.12 Reinforcement of footings 1512.1.13 Economic analysis: do not just bury concrete for no reason! 1532.2 Study of an office building on piles under axial loads 1572.2.1 Project criteria 1572.2.2 Soil data and foundation solution 1582.2.3 Soil/pile interaction parameters and loads 1592.2.4 Justification of the piles following the “Eurocodes” 1602.2.5 Comparative study of the various regulations using the MPT method 1732.2.6 Impact of the number of pile and soil tests (n) 1772.2.7 Influence of the net limit pressure of the “MPT” method 1802.2.8 Comparison of empirical methods of pile calculation 1822.2.9 Axial stiffness of deep foundations 1962.3 Horizontally loaded piles 2022.3.1 Piles under parasitic horizontal pressure: application of the G(z) method 2022.3.2 Analysis of pressures and moments using the “Tschebotarioff Method” 2082.3.3 Evaluation of the negative friction on the piles 2102.3.4 Rigidities at the top of horizontally stressed piles 2122.4 Reinforcement of deep foundations 2152.4.1 Reinforcement according to “static” standards 2152.4.2 Reinforcement by “seismic” reference bases 2182.5 Settlement of a general raft 2262.5.1 Calculation of stresses and settlements 2262.5.2 Reaction coefficient under raft 2282.5.3 Reinforcement of the raft 2332.6 Study of a road embankment on soft ground 2352.6.1 Project 2352.6.2 Data for the soil 2362.6.3 Calculation of the bearing capacity of silty clays 2392.6.4 Estimation of soil settlement under the embankment 2402.6.5 Time of consolidation settlements 240Chapter 3 Observations from Experience, Illustrative Examples, and Practical Appendices 2433.1 The case of rafts in high-rise buildings 2433.2 The case of strip footings 2483.3 Behavior of piles under an axial load 2503.4 Embankment settlement: Asaoka’s method (1978) 2513.5 Summary and useful information 2533.6 What not to do! 2583.6.1 Early 1990s: metal piles driven into chalk 2583.6.2 2010: poorly anchored piles in compact marls 2593.6.3 2008: substrate misidentified via cone penetration test 2593.6.4 2011: inadequate soil survey for pile anchoring 2603.6.5 Damage still not settled since late 2000: “collapsible soils” 2613.7 Wise conclusion 2643.8 Appendices 2653.8.1 Appendix 1: combinations of loads 2653.8.2 Appendix 2: diffusion of stresses as a function of depth 2673.8.3 Appendix 3: foundation blocks subject to overturning – methods for resolution 2833.8.4. Appendix 4: determination of the stress bulb at ultimate limit states (ULS) by the pressuremeter method according to Eurocode 7(standard NF P94 261, normative Appendix D) 2923.8.5 Appendix 5: calculation of footing stiffness 2943.8.6 Appendix 6: calculation of pile rigidities 3233.8.7 Appendix 7: bearing capacity of piles under a vertical load 3353.8.8 Appendix 8: frost protection in France 3373.8.9 Appendix 9: earthquake and soil liquefaction 339References 361French, European and ISO Standards in the Field of Geotechnics 369Index 401Summaries of Other Volumes 405