International Journal of Urban Management and Energy Sustainability

International Journal of Urban Management and Energy Sustainability

Soil Improvement Strategies for Urban Underground Construction: A Comparative Review of Conventional and Biogeotechnical Methods with Instrumentation-Based Validation

Document Type : Case Study

Author
Majid Bagheri Jamebozorgi
Department of Civil Engineering, Ke.C., Islamic Azad University, Kerman, Iran
10.22034/ijumes.2025.735864
Abstract
Urban underground construction has expanded rapidly in response to surface land scarcity and growing metropolitan transport demands. Executing tunnels, metro lines, and subsurface utilities in densely built environments introduces compounding geotechnical challenges: liquefiable loose sands, high groundwater tables, and the differential settlement sensitivity of overlying heritage and contemporary structures. Soil improvement, encompassing techniques that enhance the in-situ mechanical and hydraulic properties of problematic soils, has evolved from an optional precaution into a primary risk management instrument. This paper presents a systematic analytical review of five principal improvement methods: Tube-a-Manchette (TAM) cement grouting, vibro stone columns, deep soil mixing (DSM), biologically induced calcite precipitation (MICP), and vertical drainage. Drawing on field instrumentation datasets from three landmark projects, namely Rome Metro Line C, Mashhad Metro Line 2, and the Karbala deep excavation, the study benchmarks each method against two standardised performance indicators: Settlement Reduction Ratio (SRR) and Strength Improvement Factor (SIF). Key findings demonstrate that real-time compensation grouting reduced surface settlement by up to 75%, constraining maximum displacement to 8 mm against a 15 mm heritage-structure threshold. Deep soil mixing achieved unconfined compressive strength (UCS) exceeding 5.5 MPa and permeability of 10 to the power of negative eight m/s. MICP-based biogeotechnical methods offer a carbon footprint up to 20 times lower than cementitious alternatives but remain constrained by treatment depth and the fingering effect in heterogeneous strata. A multi-criteria sensitivity framework and research agenda for next-generation sustainable soil improvements are proposed.

Graphical Abstract

Soil Improvement Strategies for Urban Underground Construction: A Comparative Review of Conventional and Biogeotechnical Methods with Instrumentation-Based Validation

Highlights

●      Real-time compensation grouting via TAM systems reduced surface settlement by up to 75%, constraining maximum displacement to 8 mm, well below the 15 mm protection threshold for sensitive historic masonry Masini et al., 2025.

●      Deep soil mixing (DSM) achieved unconfined compressive strength (UCS) exceeding 5.5 MPa and permeability of 10^-8 m/s, satisfying both structural load-bearing and groundwater exclusion targets simultaneously Bergado et al., 2024.

●      MICP-based biogeotechnical methods offer a carbon footprint up to 20 times lower than conventional cement grouting but remain limited to depths of 15 m or less due to the fingering effect in heterogeneous urban soils Terzis et al., 2020; Zheng et al., 2025.

●      Simple Mohr-Coulomb constitutive models underestimate surface settlement in improved ground by more than 30%; Modified Cam Clay or Hardening Soil Small-Strain models are required for reliable design in soft-clay urban settings Eslami et al., 2020; Bayesteh et al., 2025.

●      A multi-criteria decision framework is proposed, weighting soil type (35%), site access constraints (25%), adjacent-structure sensitivity (20%), and project budget (20%) in the selection of soil improvement method for urban underground projects Kamon & Bergado, 1991; Bergado et al., 2024.

Keywords
Biogeotechnics
compensation grouting
settlement control
soil improvement
urban underground construction
·         Ashraf, M. S., Azahar, W. N. A. W., Marto, A., Zakaria, R., & Kassim, K. A. (2021). Enzyme-induced calcite precipitation (EICP) for ground improvement: A review. Acta Geotechnica, 16, 279-294. https://doi.org/10.3389/fbioe.2022.900881
·    Bayesteh, H., Sabermahani, M., Ostadhossein, H., & Elahi, H. (2025). Performance of a large-span deep excavation in saturated fine-grained soil adjacent to a historical building: A case study. Tunnelling and Underground Space Technology, 155, 106180. https://doi.org/10.1016/j.tust.2025.106638
·         Bergado, D. T., Chai, J. C., Alfaro, M. C., & Balasubramaniam, A. S. (2024). Improvement Techniques of Soft Ground in Subsiding and Lowland Environments (2nd ed.). CRC Press.
·         Bischetti, G. B., Di Fidio, M., & Florineth, F. (2021). Root reinforcement and slope stability: State of the art and perspectives. Ecological Engineering, 169, 106312.
·         Borden, R. H., Holtz, R. D., & Juran, I. (Eds.). (1992). Grouting, Soil Improvement and Geosynthetics (Vol. 1). ASCE.
·         Coli, M. (2023). Cited for Milan jet grouting project data: UCS = 4.2 MPa at depth
·         DeJong, J. T., et al. (2010). Biogeochemical processes and geotechnical applications: progress, opportunities and challenges. Géotechnique, 60(4), 307-325. https://doi.org/10.1680/geot.2010.60.4.307
·         Golshani, A. (2020). Evaluation of Constitutive Models in Prediction of Surface Settlements in Cohesive Soils – A Case Study: Mashhad Metro Line 2. https://doi.org/10.4417/IJGCH-05-03-04
·         Hashimoto, T., & Liu, Y. (2015). NEW TECHNOLOGIES FOR UNDERGROUND CONSTRUCTION IN SOFT GROUND OF URBAN AREA.
·         Kamon, M., & Bergado, D. T. (1991). Selection of appropriate ground improvement techniques. Proceedings of the 9th Asian Regional Conference on Soil Mechanics and Foundation Engineering (Vol. 2, pp. 1025-1035). Bangkok.
·         Lee, M., Gomez, M. G., El Kortbawi, M., & Ziotopoulou, K. (2020). Biopolymer-based soil treatment for geotechnical engineering applications. Journal of Materials in Civil Engineering, 32(7), 04020182.
·         Liu, X., & Tan, Y. (2023). Leaking accidents in water-rich sandy strata excavations: Causes and countermeasures. Tunnelling and Underground Space Technology, 135, 105089.
·         Liu, X., & Tan, Y. (2024). Seepage failure and sand erosion during deep excavation in water-rich sandy strata. Tunnelling and Underground Space Technology, 143, 105456. https://doi.org/10.1016/j.tust.2023.105456
·         Long, M. (2001). Database for retaining wall and ground movements due to deep excavations. Journal of Geotechnical and Geoenvironmental Engineering, 127(3), 203-224. https://doi.org/10.1061/(ASCE)1090-0241(2001)127:3(203)
·    Masini, L., Bergamo, F., & Rampello, S. (2025). Effect of soil improvement on ground movements induced by conventional tunnelling. Tunnelling and Underground Space Technology, 155, 106163. https://doi.org/10.1016/j.tust.2024.106163
·         Ohadian, A., Abbaspour, M., Moradi, M., & Moayed, R. Z. (2024). A review of biopolymer-based soil treatment: Applications and performance. Transportation Geotechnics, 45, 101224.
·    Ou, C. Y., Liao, J. T., & Lin, H. D. (1998). Performance of diaphragm wall constructed using top-down method. Journal of Geotechnical and Geoenvironmental Engineering, 124(9), 798-808. https://doi.org/10.1061/(ASCE)1090-0241(1998)124:9(798)
·         Simpson, B. (2014). Historical building response to nearby tunnelling. Proceedings of the ICE -- Geotechnical Engineering, 167(4), 346-357.
·         Tan, Y., Lu, Y., & Wang, D. (2023). Deep excavation-induced ground settlements in soft clays: Revisited. Computers and Geotechnics, 158, 105389.
·         Terzis, D., Bernier-Latmani, R., & Laloui, L. (2020). Field-scale bio-cementation tests and pore fluid chemistry monitoring. Geotechnique, 70(11), 989-1001.
·         Zheng, X., Shu, S., Chen, J., Yang, J., & Zhong, P. (2025). Bioengineering of soils for ground improvement and stability: A review of nature-based technologies. Environmental Challenges, 20, 101293.
International Journal of Urban Management and Energy Sustainability
Volume 6, Issue 3 - Serial Number 3
Summer 2025
Pages 275-284

  • Receive Date 10 March 2025
  • Revise Date 29 May 2025
  • Accept Date 02 July 2025