Observed Performance and Analysis of SEM Cavern Construction in Downtown Los Angeles
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 147, Issue 11
Abstract
The Regional Connector Transit Corridor (RCTC) project consists of an 89-m long, 17.7-m wide, and 11-m high span crossover cavern constructed beneath critical infrastructure using the sequential excavation method (SEM) at relatively shallow depth (15 m below ground surface) in downtown Los Angeles. The cavern construction involved a complex three-drift, two-sidewall configuration and was excavated in the Fernando formation, a weak clayey siltstone. This paper presents a comprehensive case study of the cavern excavation and initial support construction. The performance of the urban SEM was assessed and complex ground behavior was examined once per excavation step during the construction process. The overall average surface settlement was 20 mm and the largest single-stage incremental movements occurred in the center bench and invert excavation, accounting for 30%–40% of the total deformation. The subsurface experienced less differential settlement during the side drift excavations due to the ovate excavation profile and the restriction from surrounding infrastructure. The measured center crown vertical displacement varied between 5 and 10 mm and the center invert initial support was recorded to heave 8–12 mm. A systematic procedure was developed to apply a deliberate observational method. The lessons learned support that appropriate real-time analysis improves the quality of regular data review, continuously updating the knowledge of risk and enabling prompt adaptions and optimizations of the design and construction along the SEM tunneling process.
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Data Availability Statement
Some or all data, models, or code generated or used during the study are proprietary or confidential in nature and may only be provided with restrictions. These include all field measurement data interpreted in the paper.
Acknowledgments
Partial funding for this study was provided by Skanska and Traylor Bros., as well by the University Transportation Center for Underground Transportation Infrastructure (UTC-UTI) at the Colorado School of Mines under Grant No. 69A3551747118 from the USDOT. We would also like to express our gratitude to Traylor Bros., Skanska, Mott MacDonald, Geocomp, Sixense Soldata, and LA Metro for sharing the project data and providing the opportunity to join in this project.
References
Ağbay, E., and T. Topal. 2020. “Evaluation of twin tunnel-induced surface ground deformation by empirical and numerical analyses (NATM part of Eurasia tunnel, Turkey).” Comput. Geotech. 119 (Mar): 103367. https://doi.org/10.1016/j.compgeo.2019.103367.
Brodbaek, C., D. Penrice, J. Coibion, and C. Frederick. 2018. “Downtown Bellevue tunnel—Analysis and design of SEM optimization.” In Proc., of the North American Tunneling Conf. 2018. Englewood, CO: Society for Mining, Metallurgy, and Exploration.
CEN (European Committee for Standardization). 2004. Geotechnical design—Part 1: General rules. Brussels, Belgium: CEN.
Clarke, B. G. 1997. “Pressuremeter testing in ground investigation. Part II—Interpretation.” Proc. Inst. Civ. Eng. Geotech. Eng. 125 (1): 42–52. https://doi.org/10.1680/igeng.1997.28996.
Deane, A. P., and R. H. Bassett. 2007. “The Heathrow express trial tunnel.” Proc. Inst. Civ. Eng. Geotech. Eng. 113 (3): 144–156. https://doi.org/10.1680/igeng.1995.27810.
Dindarloo, S. R., and E. Siami-Irdemoosa. 2015. “Maximum surface settlement based classification of shallow tunnels in soft ground.” Tunnelling Underground Space Technol. 49 (Jun): 320–327. https://doi.org/10.1016/j.tust.2015.04.021.
Fang, Q., D. Zhang, and L. N. Y. Wong. 2012. “Shallow tunnelling method (STM) for subway station construction in soft ground.” Tunnelling Underground Space Technol. 29 (May): 10–30. https://doi.org/10.1016/j.tust.2011.12.007.
Fargnoli, V., D. Boldini, and A. Amorosi. 2013. “TBM tunnelling-induced settlements in coarse-grained soils: The case of the new Milan underground line 5.” Tunnelling Underground Space Technol. 38 (Sep): 336–347. https://doi.org/10.1016/j.tust.2013.07.015.
Herranz, C., C. Bragard, I. Hee, and D. Cerulli. 2019. “SEM cavern construction in Downtown LA.” In Proc., Rapid Excavation & Tunneling Conf., 1037–1050. Reston, VA: ASCE.
Herranz, C., and D. Penrice. 2018. “Mining under Downtown Los Angeles.” Ita-aites.cz 27 (4): 4–14.
Herranz, C., D. Penrice, J. Lianides, and Z. Horvath. 2016. “SEM crossover cavern in Downtown L.A.” In Proc., Geotechnical and Structural Engineering Congress, 2043–2053. Reston, VA: ASCE.
HSE (Health and Safety Executive). 1996. Safety of New Austrian tunnelling method (NATM) tunnels: A review of sprayed concrete tunnels with particular reference to London clay, 80. Sudbury, UK: HSE.
ICE (Institution of Civil Engineers). 1996. Sprayed concrete linings (NATM) for tunnels in soft ground, ICE design and practice guide, 88. London: Thomas Telford.
Ieronymaki, E. S., A. J. Whittle, and D. S. Sureda. 2017. “Interpretation of free-field ground movements caused by mechanized tunnel construction.” J. Geotech. Geoenviron. Eng. 143 (4): 04016114. https://doi.org/10.1061/(ASCE)GT.1943-5606.0001632.
Jin, D., D. Yuan, X. Li, and H. Zheng. 2018. “Analysis of the settlement of an existing tunnel induced by shield tunneling underneath.” Tunnelling Underground Space Technol. 81 (Nov): 209–220. https://doi.org/10.1016/j.tust.2018.06.035.
Karakus, M., and R. J. Fowell. 2004. “An insight into the New Austrian Tunnelling Method (NATM).” In Proc., 7th Regional Rock Mechanics Symp. Sivas, Turkey: Cumhuriyet Üniversitesi Maden Mühendisliği Bölümü, Türk Ulusal Kaya Mekaniği Derneği.
Kovari, K. 1994. “Erroneous concepts behind the new Austrian tunnelling method.” Tunnels Tunnelling 26 (11): 38–42.
Kovári, K., and P. Lunardi. 2000. “On the observational method in tunnelling.” In Proc., ISRM Int. Symp. Richardson, TX: OnePetro.
Lamar, D. L. 1970. Geology of the Elysian Park-Repetto Hills Area, Los Angeles County, California. San Francisco: Div. of Mines and Geology.
Lunardi, P. 2008. Design and construction of tunnels: Analysis of controlled deformations in rock and soils (ADECO-RS). Berlin: Springer.
Mair, R. J. 2008. “Tunnelling and geotechnics: New horizons.” Géotechnique 58 (9): 695–736. https://doi.org/10.1680/geot.2008.58.9.695.
Mair, R. J., and D. M. Wood. 2013. Pressuremeter testing: Methods and interpretation. Amsterdam, Netherlands: Elsevier.
METRO (Los Angeles Metropolitan Transit Authority). 2013. “Metro rail design criteria section 5 appendix metro supplemental seismic design criteria.” Accessed April 5, 2013. https://partners.skanska.com/usa/clients/lametro/rctc/PreCon/OwnDoc/RFP/Original%20RFP/Vol%20II%20-%20Project%20Definition%20Documents/1.%20Metro%20Rail%20Design%20Criteria/Metro%20Rail%20Design%20Criteria%20Section%2005%20Structural-Geotechnical%20Rev%204%20101612.pdf.
Moritz, B., R. Matt, F. Graf, and M. Brandtner. 2008. “Advanced observation techniques for sophisticated shallow tunnel projects–experience gained using innovative monitoring methods at the Lainzer tunnel LT31.” Geomechanik Tunnelbau: Geomechanik Tunnelbau 1 (5): 466–476. https://doi.org/10.1002/geot.200800051.
Munfah, N., V. Gall, and S. Matthei. 2016. “Recent trends in conventional tunneling (SEM/NATM) in the US.” In Vol. 1 of Proc., ITA-AITES World Tunnel Congress 2016, WTC 2016, 505–514. Englewood, CO: Society for Mining, Metallurgy, and Exploration.
New, B. M., and K. H. Bowers. 1994. “Ground movement model validation at the heathrow express trial tunnel.” In Tunnelling’94, 301–329. Boston: Springer.
Nicholson, D., C. M. Tse, C. Penny, S. O. Hana, and R. Dimmock. 1999. Vol. 185 of The observational method in ground engineering: Principles and applications. London: Construction Industry Research and Information Association.
Peck, R. B. 1969. “Advantages and limitations of the observational method in applied soil mechanics.” Géotechnique 19 (2): 171–187. https://doi.org/10.1680/geot.1969.19.2.171.
Phelps, D. J., J. Gildner, C. Tattersall, J. Laubbichler, and D. McAllister. 2005. “Design and risk management strategy for the Sound Transit Beacon Hill Station and tunnels.” In Proc., 2005 RETC. Englewood, CO: Society for Mining, Metallurgy, and Exploration.
Pinto, F., D. M. Zymnis, and A. J. Whittle. 2014. “Ground movements due to shallow tunnels in soft ground. II: Analytical interpretation and prediction.” J. Geotech. Geoenviron. Eng. 140 (4): 04013041. https://doi.org/10.1061/(ASCE)GT.1943-5606.0000947.
Sabatini, P. J., R. C. Bachus, P. W. Mayne, J. A. Schneider, and T. E. Zettler. 2002. Geotechnical engineering circular No. 5 evaluation of soil and rock properties. Washington, DC: Federal Highway Administration, Office of Bridge Technology.
Sandstrom, G. E. 1963. History of tunnelling. London: Barrie & Rockcliff.
Sharifzadeh, M., F. Kolivand, M. Ghorbani, and S. Yasrobi. 2013. “Design of sequential excavation method for large span urban tunnels in soft ground–Niayesh tunnel.” Tunnelling Underground Space Technol. 35 (Apr): 178–188. https://doi.org/10.1016/j.tust.2013.01.002.
Spyridis, P., P. Fortsakis, and T. Schwind. 2018. “Geotechnical engineering and innovative support system for shallow urban subway caverns in rock, in confined built environment.” Geotech. Geol. Eng. 36 (5): 2967–2983. https://doi.org/10.1007/s10706-018-0516-9.
Ssenyonga, A. 2018. “An investigation of surface settlement and volume loss associated with SCL tunnelling at Stepney Green.” In Crossrail project: Infrastructure design and construction, 1–38. London: ICE Publishing.
Thomas, A. 2019. Sprayed concrete lined tunnels. Boca Raton, FL: CRC Press.
Tonon, F. 2010. “Sequential excavation, NATM and ADECO: What they have in common and how they differ.” Tunnelling Underground Space Technol. 25 (3): 245–265. https://doi.org/10.1016/j.tust.2009.12.004.
Ulusay, R. 2014. The ISRM suggested methods for rock characterization, testing and monitoring: 2007-2014. Cham, Switzerland: Springer.
van der Berg, J. P., C. R. I. Clayton, and D. B. Powell. 2003. “Displacements ahead of an advancing NATM tunnel in the London clay.” Géotechnique 53 (9): 767–784. https://doi.org/10.1680/geot.2003.53.9.767.
Von Rabcewicz, L. 1964. “The new Austrian tunnelling method.” Water Power 65 (Nov): 453–457.
Vorster, T. E., A. Klar, K. Soga, and R. J. Mair. 2005. “Estimating the effects of tunneling on existing pipelines.” J. Geotech. Geoenviron. Eng. 131 (11): 1399–1410. https://doi.org/10.1061/(ASCE)1090-0241(2005)131:11(1399).
Wu, T. H. 2011. “2008 Peck lecture: The observational method: Case history and models.” J. Geotech. Geoenviron. Eng. 137 (10): 862–873. https://doi.org/10.1061/(ASCE)GT.1943-5606.0000509.
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Journal of Geotechnical and Geoenvironmental Engineering
Volume 147 • Issue 11 • November 2021
Copyright
© 2021 American Society of Civil Engineers.
History
Received: Nov 21, 2020
Accepted: Jun 15, 2021
Published online: Sep 8, 2021
Published in print: Nov 1, 2021
Discussion open until: Feb 8, 2022
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