Figure 1
Plasticity chart data for 9 sites west of the city of Rio de Janeiro (
Baroni &Almeida, 2017Baroni, M., & Almeida, M. (2017). Compressibility and stress history of very soft organic clays. Geotechnical Engineering, 170(2), 148-160. http://dx.doi.org/10.1680/jgeen.16.00146.
http://dx.doi.org/10.1680/jgeen.16.00146...
).
Figure 2
Stage-constructed embankment with PVDs, reinforcement and berms on an extremely soft soil (Almeida et al., 2008Almeida, M.S.S., Marques, M.E.S., Lima, B.T., & Alvez, F. (2008). Failure of a reinforced embankment an extremely soft peat clay layer. In Eurogeo4 (Vol. 1, pp. 1-8), Scotland.).
Figure 3
Normalized embankment stresses versus normalized settlements for different ground improvement techniques (adapted from
Springman et al., 2012Springman, S.M., Laue, J., Askarinejad, A., & Gautray, J.N.F. (2012). On the design of ground improvement for embankements on soft ground. In Proceedings of the International Conference on Ground Improvement and Ground Control: Transport Infrastructure Development and Natural Hazards Mitigation (Vol. 1, pp. 67-83), Wollongong, Australia. http://dx.doi.org/10.3850/978-981-07-3559-3_101-0006.
http://dx.doi.org/10.3850/978-981-07-355...
).
Figure 4
Vacuum consolidation technique: (a) with membrane (b) drain-to-drain (membraneless) (c) detail of connectors in the drain to drain configuration (adapted from
Freitas, 2021Freitas, M.D.S. (2021). Técnica de vácuo em solos moles aplicada a infraestrutura de transportes [Master’s dissertation]. Military Institute of Engineering (in Portuguese). Retrieved in July 23, 2022, from https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=11152264
https://sucupira.capes.gov.br/sucupira/p...
).
Figure 5
(a) Saint-Roch-de-l’Achigan embankment test cross section and instrumentation. (
Marques & Leroueil, 2015Marques, M.E.S., & Leroueil, S. (2015). Vacuum consolidation and vacuum consolidation with heating. In B. Indraratna, J. Chu & C. Rujikiatkamjorn (Eds.), Ground improvement series: chemical, electrokinetic, thermal and bioengineering (Vol. 3, pp. 537-554). Amsterdam: Elsevier. http://dx.doi.org/10.1016/B978-0-08-100191-2.00017-4.
http://dx.doi.org/10.1016/B978-0-08-1001...
); (b) Variation over time for vacuum pressure, embankment thickness and horizontal displacements
Ux (field and numerical values) at points
B and
C at inclinometer
IA1 (
Almeida et al. 2021Almeida, M.S.S., Deotti, L., Almeida, M.C.F., Marques, M.E.S., & Cardoso, I.M. (2021). Vacuum preloading on structured clay: field, laboratory and numerical studies. International Journal of Geomechanics, 1(10), 21. http://dx.doi.org/10.1061/(ASCE)GM.1943-5622.0002170.
http://dx.doi.org/10.1061/(ASCE)GM.1943-...
).
Figure 6
Numerical analysis: (a) FE mesh and points analyzed; (b) Stress paths at points A and B.
Figure 7
Vacuum application layout and settlement plates location (
Freitas, 2021Freitas, M.D.S. (2021). Técnica de vácuo em solos moles aplicada a infraestrutura de transportes [Master’s dissertation]. Military Institute of Engineering (in Portuguese). Retrieved in July 23, 2022, from https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=11152264
https://sucupira.capes.gov.br/sucupira/p...
).
Figure 8
Drain-to-drain vacuum consolidation: (a) vertical drains and installation of collectors (b) pumps and collector tubes (c) detail of embankment construction over collectors and connections (
Freitas, 2021Freitas, M.D.S. (2021). Técnica de vácuo em solos moles aplicada a infraestrutura de transportes [Master’s dissertation]. Military Institute of Engineering (in Portuguese). Retrieved in July 23, 2022, from https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=11152264
https://sucupira.capes.gov.br/sucupira/p...
).
Figure 9
Settlement values measured at SP03 and settlement predictions for vacuum of 30 kPa or 70 kPa.
Figure 10
Settlement reduction factor versus inverse of area replacement ratio (see
McCabe et al., 2009McCabe, B.A., Nimmons, G.J., & Egan, D. (2009). A review of field performance of stone columns in soft soils. Geotechnical Engineering, 162(6), 323-334. http://dx.doi.org/10.1680/geng.2009.162.6.323.
http://dx.doi.org/10.1680/geng.2009.162....
for the other case histories).
Figure 11
Layout of the test area and instrumentation (Almeida et al., 2014Almeida, M.S.S., Lima, B.T., Riccio, M.V.F., Jud, H., Almeida, M.C.F., & Roza, F. (2014). Stone columns field test: monitoring data and numerical analyses. Geotechnical Engineering Journal of the SEAGS and AGSSEA, 45(1), 103-112.).
Figure 12
Vertical (a) and horizontal - Inclinometer I2 (b) displacements at instrumentation (Almeida et al., 2014Almeida, M.S.S., Lima, B.T., Riccio, M.V.F., Jud, H., Almeida, M.C.F., & Roza, F. (2014). Stone columns field test: monitoring data and numerical analyses. Geotechnical Engineering Journal of the SEAGS and AGSSEA, 45(1), 103-112.).
Figure 13
Excess pore-pressure (Almeida et al., 2014Almeida, M.S.S., Lima, B.T., Riccio, M.V.F., Jud, H., Almeida, M.C.F., & Roza, F. (2014). Stone columns field test: monitoring data and numerical analyses. Geotechnical Engineering Journal of the SEAGS and AGSSEA, 45(1), 103-112.).
Figure 14
Horizontal stress (Almeida et al., 2014Almeida, M.S.S., Lima, B.T., Riccio, M.V.F., Jud, H., Almeida, M.C.F., & Roza, F. (2014). Stone columns field test: monitoring data and numerical analyses. Geotechnical Engineering Journal of the SEAGS and AGSSEA, 45(1), 103-112.).
Figure 15
Instrumentation positions in the studied section (dimensions in meter) (
Lima et al., 2019Lima, B.T., Almeida, M.S.S., & Hosseinpour, I. (2019). Field measured and simulated performance of a stone columns-strengthened soft clay deposit. International Journal of Geotechnical Engineering, 16(6), 776-785. http://dx.doi.org/10.1080/19386362.2019.1653506.
http://dx.doi.org/10.1080/19386362.2019....
).
Figure 16
Measured and predicted settlements versus time at northern stack (
Lima et al., 2019Lima, B.T., Almeida, M.S.S., & Hosseinpour, I. (2019). Field measured and simulated performance of a stone columns-strengthened soft clay deposit. International Journal of Geotechnical Engineering, 16(6), 776-785. http://dx.doi.org/10.1080/19386362.2019.1653506.
http://dx.doi.org/10.1080/19386362.2019....
).
Figure 17
Comparison between measured settlements and predictions from finite element analysis (Riccio Filho et al., 2022).
Figure 18
Geotechnical properties of soft clay layers: (a) typical soil profile, (b) compressibility ratio (CR), (c) profile of undrained shear strength (
Almeida et al., 2015Almeida, M.S.S., Hosseinpour, I., Riccio, M., & Alexiew, D. (2015). Behavior of geotextile-encased granular columns supporting test embankment on soft deposit. Journal of Geotechnical and Geoenvironmental Engineering, 141(3), 04014116. http://dx.doi.org/10.1061/(ASCE)GT.1943-5606.0001256.
http://dx.doi.org/10.1061/(ASCE)GT.1943-...
).
Figure 19
Embankment side view and position of instruments (
Almeida et al., 2015Almeida, M.S.S., Hosseinpour, I., Riccio, M., & Alexiew, D. (2015). Behavior of geotextile-encased granular columns supporting test embankment on soft deposit. Journal of Geotechnical and Geoenvironmental Engineering, 141(3), 04014116. http://dx.doi.org/10.1061/(ASCE)GT.1943-5606.0001256.
http://dx.doi.org/10.1061/(ASCE)GT.1943-...
).
Figure 20
Variation of settlement over the encased column and soft soil (
Hosseinpour et al., 2015Hosseinpour, I., Almeida, M.S.S., & Riccio, M. (2015). Full-scale load test and finite-element analysis of soft ground improved by geotextile-encased granular columns. Geosynthetics International, 22(6), 428-438. http://dx.doi.org/10.1680/jgein.15.00023.
http://dx.doi.org/10.1680/jgein.15.00023...
).
Figure 21
Settlement improvement factor for present test embankment compared with previous case histories (adapted from
Almeida et al., 2018bAlmeida, M.S.S., Riccio Filho, M., Hosseinpour, I., & Alexiew, D. (2018b). Geosynthetic encased columns for soft soil improvement. London: CRC Press. http://dx.doi.org/10.1201/9781315177144.
http://dx.doi.org/10.1201/9781315177144...
).
Figure 22
Measurements by stress cells: (a) total vertical stress, (b) stress concentration factor (
Hosseinpour et al., 2015Hosseinpour, I., Almeida, M.S.S., & Riccio, M. (2015). Full-scale load test and finite-element analysis of soft ground improved by geotextile-encased granular columns. Geosynthetics International, 22(6), 428-438. http://dx.doi.org/10.1680/jgein.15.00023.
http://dx.doi.org/10.1680/jgein.15.00023...
).
Figure 23
Maximum settlement vs. vertical applied stress for reinforced embankment (
RE1,Magnani et al., 2010Magnani, H.O., Ehrlich, M., & Almeida, M.S.S. (2010). Embankments over soft clay deposits: contribution of basal reinforcement and surface sand layer to stability. Journal of Geotechnical and Geoenvironmental Engineering, 136(1), 260-264. http://dx.doi.org/10.1061/(ASCE)GT.1943-5606.0000200.
http://dx.doi.org/10.1061/(ASCE)GT.1943-...
) and improved (
GEC1,Hosseinpour et al., 2016Hosseinpour, I., Almeida, M.S.S., Riccio, M.V.F. (2016). Ground improvement of soft soil by geotextile-encased columns. Proceedings of the ICE - Ground Improvement, 169, 297-305.) foundations.
Figure 24
Maximum horizontal displacements vs. vertical applied stress for reinforced embankment (
RTE,Magnani et al., 2010Magnani, H.O., Ehrlich, M., & Almeida, M.S.S. (2010). Embankments over soft clay deposits: contribution of basal reinforcement and surface sand layer to stability. Journal of Geotechnical and Geoenvironmental Engineering, 136(1), 260-264. http://dx.doi.org/10.1061/(ASCE)GT.1943-5606.0000200.
http://dx.doi.org/10.1061/(ASCE)GT.1943-...
) and improved (
PTE,Hosseinpour et al., 2016Hosseinpour, I., Almeida, M.S.S., Riccio, M.V.F. (2016). Ground improvement of soft soil by geotextile-encased columns. Proceedings of the ICE - Ground Improvement, 169, 297-305.) foundations.
Figure 25
Embankment settlement vs. horizontal displacements for reinforced embankment (RE1,
Magnani et al., 2010Magnani, H.O., Ehrlich, M., & Almeida, M.S.S. (2010). Embankments over soft clay deposits: contribution of basal reinforcement and surface sand layer to stability. Journal of Geotechnical and Geoenvironmental Engineering, 136(1), 260-264. http://dx.doi.org/10.1061/(ASCE)GT.1943-5606.0000200.
http://dx.doi.org/10.1061/(ASCE)GT.1943-...
) and improved (GEC1,
Hosseinpour et al., 2016Hosseinpour, I., Almeida, M.S.S., Riccio, M.V.F. (2016). Ground improvement of soft soil by geotextile-encased columns. Proceedings of the ICE - Ground Improvement, 169, 297-305.) foundations.
Figure 26
Excess pore pressure and total load vs. time for reinforced embankment (
RE1,Magnani et al., 2010Magnani, H.O., Ehrlich, M., & Almeida, M.S.S. (2010). Embankments over soft clay deposits: contribution of basal reinforcement and surface sand layer to stability. Journal of Geotechnical and Geoenvironmental Engineering, 136(1), 260-264. http://dx.doi.org/10.1061/(ASCE)GT.1943-5606.0000200.
http://dx.doi.org/10.1061/(ASCE)GT.1943-...
) and improved (
GEC1,Hosseinpour et al., 2016Hosseinpour, I., Almeida, M.S.S., Riccio, M.V.F. (2016). Ground improvement of soft soil by geotextile-encased columns. Proceedings of the ICE - Ground Improvement, 169, 297-305.) foundations.
Figure 27
Piled embankments: (a) schematic representation of load transfer mechanisms, (b) distribution of the load parts B and C in the geosynthetic reinforcement, (c) definition of geometric configuration and unit cell (adapted from
Fagundes et al., 2017Fagundes, D.F., Almeida, M.S.S., Thorel, L., & Blanc, M. (2017). Load transfer mechanism and deformation of reinforced piled embankments. Geotextiles and Geomembranes, 45(2), 1-10. http://dx.doi.org/10.1016/j.geotexmem.2016.11.002.
http://dx.doi.org/10.1016/j.geotexmem.20...
).
Figure 28
Influence of the geosynthetic in the load efficiency: (a) differences in the load efficiency between tests conducted with and without geosynthetic, (b) efficiency improvement to different test configurations (adapted from
Fagundes et al., 2017Fagundes, D.F., Almeida, M.S.S., Thorel, L., & Blanc, M. (2017). Load transfer mechanism and deformation of reinforced piled embankments. Geotextiles and Geomembranes, 45(2), 1-10. http://dx.doi.org/10.1016/j.geotexmem.2016.11.002.
http://dx.doi.org/10.1016/j.geotexmem.20...
).
Figure 29
Comparison between the maximum deflection zd observed experimentally (from Emax) and predicted by analytical methods: (a) BS006 (2012) and (b) EBGEO (2011)EBGEO. (2011). Recommendations for design and analysis of earth structures using geosynthetic reinforcements. Deutsche Gesellschaft für Geotechnik e.V. (DGGT), Berlin. (adapted from Almeida, 2019Almeida, M.S.S. (2019). Soft ground improvement: field and numerical studies. In XVI Pan-American Conference on Soil Mechanics and Geotechnical Engineering (Keynote Lecture of Technical Session, No. 5, “Soft soils”), Cancun, Mexico.).
Figure 30
(a) and (b) Surface view of the embankment and (c) the (Δ
u/Δ
ω)
vs H/(
s -
d) for all configurations (adapted from
Fagundes et al., 2015Fagundes, D.F., Almeida, M.S.S., Girout, R., Blanc, M., & Thorel, L. (2015). Behaviour of piled embankment without reinforcement. Geotechnical Engineering, 168(6), 514-525. http://dx.doi.org/10.1680/jgeen.14.00155.
http://dx.doi.org/10.1680/jgeen.14.00155...
,
2017Fagundes, D.F., Almeida, M.S.S., Thorel, L., & Blanc, M. (2017). Load transfer mechanism and deformation of reinforced piled embankments. Geotextiles and Geomembranes, 45(2), 1-10. http://dx.doi.org/10.1016/j.geotexmem.2016.11.002.
http://dx.doi.org/10.1016/j.geotexmem.20...
).
Figure 31
3D View of the numerical model; vertical displacements to a CF3_J1 and different embankment heights.
Figure 32
Maximum tensile force of the geosynthetic as a function of the embankment height obtained with the numerical models and the analytical method: a) Jx = 4760 kN/m; b) Jy = 2960 kN/m (adapted from Almeida, 2019Almeida, M.S.S. (2019). Soft ground improvement: field and numerical studies. In XVI Pan-American Conference on Soil Mechanics and Geotechnical Engineering (Keynote Lecture of Technical Session, No. 5, “Soft soils”), Cancun, Mexico.).
Figure 33
Typical use of DSM columns with diameter d for piled embankment on soft soils, piles spaced s center to center.
Figure 34
Increase in the q
u with time (days) for mixtures 1-7, adapted from
Machado (2016)Machado, M.C.B. (2016). Treatment of clayey soft soils by cement mixtures in deep [Master’s dissertation]. Federal University of Rio de Janeiro’ repository (in Portuguese). Retrieved in July 23, 2022, from http://www.coc.ufrj.br/pt/dissertacoes-de-mestrado/389-msc-pt-2016/4683-michelle-christini-de-brito-machado
http://www.coc.ufrj.br/pt/dissertacoes-d...
.
Figure 35
Comparison between numerical predictions and settlements measured in the field (Test Area 2), adapted from
Assis (2016)Assis, V.C. (2016). Structured embankment on soft soil over DSM columns [Master’s dissertation]. Federal University of Rio de Janeiro’ repository (in Portuguese). Retrieved in July 26, 2022, from http://www.coc.ufrj.br/pt/dissertacoes-de-mestrado/389-msc-pt-2016/4696-vinicius-cardoso-de-assis
http://www.coc.ufrj.br/pt/dissertacoes-d...
.
Figure 36
Evolution of
qu with time, field tests (
Ávila, 2021Ávila, C.T.B. (2021). Structured embankment over columns with soil cement mixture [Master’s dissertation]. Federal University of Juiz de Fora’ repository (in Portuguese). Retrieved in July 26, 2022, from https://www2.ufjf.br/pec/wp-content/uploads/sites/115/2022/02/Disserta%C3%A7%C3%A3o-102470031.pdf
https://www2.ufjf.br/pec/wp-content/uplo...
).
Figure 37
Evolution of the settlements, column top (
SPOC) and between columns (
SPOG1 and
SPOG1) over the time, adapted from
Ávila (2021)Ávila, C.T.B. (2021). Structured embankment over columns with soil cement mixture [Master’s dissertation]. Federal University of Juiz de Fora’ repository (in Portuguese). Retrieved in July 26, 2022, from https://www2.ufjf.br/pec/wp-content/uploads/sites/115/2022/02/Disserta%C3%A7%C3%A3o-102470031.pdf
https://www2.ufjf.br/pec/wp-content/uplo...
.
Figure 38
Evolution of the
n over time (
Ávila, 2021Ávila, C.T.B. (2021). Structured embankment over columns with soil cement mixture [Master’s dissertation]. Federal University of Juiz de Fora’ repository (in Portuguese). Retrieved in July 26, 2022, from https://www2.ufjf.br/pec/wp-content/uploads/sites/115/2022/02/Disserta%C3%A7%C3%A3o-102470031.pdf
https://www2.ufjf.br/pec/wp-content/uplo...
).
Figure 39
SSM technology (Adapted from Andrade at al., 2010Andrade, G.G., Lopes, A.N., Antunes, R.P., & Dias, D.R. (2010). Experiências Brasileiras com estabilização de solos moles saturados através de sistema Dry-Mix - STABTEC. In Anais do XV Congresso Brasileiro de Mecânica dos Solos e Engenharia Geotécnica (pp. 1-6), Gramado. ABMS, CBMR, ISRM and SPG (in Portuguese).).
Figure 40
Geotechnical profile of the soft soil deposit:
SPT for unstabilized and stabilized test results (Adapted from
Lemos et al., 2020Lemos, S.G.F.P., Almeida, M.S.S., Consoli, N.C., Nascimento, T.Z., & Polido, U.F. (2020). Field and laboratory investigation of highly organic clay stabilized with Portland cement. Journal of Materials in Civil Engineering, 32(4), 04020063. http://dx.doi.org/10.1061/(ASCE)MT.1943-5533.0003111.
http://dx.doi.org/10.1061/(ASCE)MT.1943-...
).
Figure 41
Unconfined compressive strength (
qu) relative to secant modulus (
E50) for 18 kPa preloaded and non-preloaded laboratory and field specimens (Adapted from
Lemos et al., 2020Lemos, S.G.F.P., Almeida, M.S.S., Consoli, N.C., Nascimento, T.Z., & Polido, U.F. (2020). Field and laboratory investigation of highly organic clay stabilized with Portland cement. Journal of Materials in Civil Engineering, 32(4), 04020063. http://dx.doi.org/10.1061/(ASCE)MT.1943-5533.0003111.
http://dx.doi.org/10.1061/(ASCE)MT.1943-...
).
Figure 42
Geotechnical profile of the soft soil deposit, SPT and CPTu test results.
Figure 43
Average results for the unconfined compression strength; non-preloaded and preloaded tests with 18 kPa.
Figure 44
Embankment settlement monitoring.
Figure 45
Typical CPR grouting layout plans. The area of the unit cell is shaded.
Figure 46
Ground improvement at the Athletes Park by means of CPR grouting. Courtesy of Engegraut ltda.
Figure 47
Comparison of settlement vs time curves at Recreio dos Bandeirantes (Riccio Filho et al., 2020).
Table 1
Soil parameter values for clay layers 1 to 3 (Almeida et al., 2014Almeida, M.S.S., Lima, B.T., Riccio, M.V.F., Jud, H., Almeida, M.C.F., & Roza, F. (2014). Stone columns field test: monitoring data and numerical analyses. Geotechnical Engineering Journal of the SEAGS and AGSSEA, 45(1), 103-112.).
Table 2
Limit equilibrium stability analyses for the end of construction condition (Riccio Filho et al., 2022, adapted).
Table 3
Centrifuge tests configurations.
Table 4
Characteristics of the soft soil in the Salgado Filho airport (
Machado, 2016Machado, M.C.B. (2016). Treatment of clayey soft soils by cement mixtures in deep [Master’s dissertation]. Federal University of Rio de Janeiro’ repository (in Portuguese). Retrieved in July 23, 2022, from http://www.coc.ufrj.br/pt/dissertacoes-de-mestrado/389-msc-pt-2016/4683-michelle-christini-de-brito-machado
http://www.coc.ufrj.br/pt/dissertacoes-d...
).
Table 5
Soft soil properties
Table 6
Typical range of β values as a function of soft soil improvement techniques.