Analysis of Excavation Support Systems Considering the Influence of Saturated and Unsaturated Soil Conditions
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 148, Issue 6
Abstract
A well-established framework for the design of excavation support systems (ESSs) is not available in the literature. Several guidelines that have evolved from engineering practice are conventionally used in the design of ESSs. The key indicators for judging the performance of ESSs are wall deformation, internal wall stresses, and surface soil settlement information. There is evidence from several case studies that the measured wall deformations are typically lower than the predicted values. Such behavior may be attributed to ignoring the influence of capillary suction. The key objective of the study presented in this paper is twofold; the first is highlighting limitations in the current design practice and the second is to pave the way for comprehensive design of ESSs. This is achieved by undertaking numerical analysis on a silty clay taking account of the influence of saturated and unsaturated soil conditions to investigate the performance of ESSs based on a rational design approach. In addition, the proposed approach is validated based on wall deflections information using the published results of a case history. The proposed approach is promising for implementing the mechanics of unsaturated soils in geotechnical engineering practice for the rational design of ESSs. The paper also highlights some limitations of the present study and the need for future studies to provide verifications using more case histories.
Get full access to this article
View all available purchase options and get full access to this article.
Data Availability Statement
Some or all data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request. These items include detailed output for all analyzed scenarios.
Acknowledgments
We appreciate the anonymous reviewers’ comprehensive comments and constructive criticism that contributed significantly to improve this paper.
References
Adem, H. H., and S. K. Vanapalli. 2013. “A simple approach for predicting vertical movements of expansive soils using the mechanics of unsaturated soils.” In Proc., 18th Int. Conf. on Soil Mechanics and Geotechnical Engineering. London: International Society for Soil Mechanics and Geotechnical Engineering.
Anderson, J. B., V. Ogunro, J. Detwiler, J. Starnes, and R. Burrage. 2008. Development of an earth pressure model for design of earth retaining structures in piedmont soil. Raleigh, NC: North Carolina DOT.
ASTM. 2016. Standard test methods for determination of the soil water characteristic curve for desorption using a hanging column, pressure extractor, chilled mirror hygrometer, and/or centrifuge. ASTM D6836. West Conshohocken, PA: ASTM.
Bica, A. V. D., H. Blum, C. Clayton, P. Rowe, H. Krey, and J. Brinch Hansen. 1989. “Limit equilibrium design methods for free embedded cantilever walls in granular materials.” Proc. Inst. Civ. Eng. 86 (5): 879–898. https://doi.org/10.1680/iicep.1989.3161.
Borden, R. H., M. A. Gabr, J. Lee, C.-T. Tang, and C. Wang. 2016. Design of temporary slopes and excavations in NC residual soils. Raleigh, NC: North Carolina DOT.
BSI (British Standards Institution). 2007. Design of steel structures. EN 1993-5. London: BSI.
Catana, M. C., S. K. Vanapalli, and V. K. Garga. 2006. “The water retention characteristics of compacted clays.” In Proc., 4th Int. Conf. on Unsaturated Soils 2006, 1348–1359. Reston, VA: ASCE.
CEN (European Committee for Standardization). 1993. Design of steel structures. Brussels, Belgium: CEN.
CGS (Canadian Geotechnical Society). 2006. Canadian foundation engineering manual. Richmond, BC, Canada: CGS.
Chin, K. B., E. C. Leong, and H. Rahardjo. 2010. “A simplified method to estimate the soil-water characteristic curve.” Can. Geotech. J. 47 (12): 1382–1400. https://doi.org/10.1139/T10-033.
Chini, S. A., and G. Genauer. 1997. “Excavation support systems for construction operations.” J. Construct. Educ. 2 (3): 156–170.
Clough, G. W., and A. I. Mana. 1977. “Lessons learnt in finite element analysis of temporary excavations in soft clay.” In Proc., 2nd Int. Conf. on Numerical Methods in Geomechanics, 496–510. New York: ASCE.
Clough, G. W., and Y. Tsui. 1974. “Performance of tied-back walls in clay.” J. Geotech. Eng. Div. 100 (12): 1259–1273. https://doi.org/10.1061/AJGEB6.0000128.
Day, R. A. 1999. “Net pressure analysis of cantilever sheet pile walls.” Géotechnique 49 (2): 231–245. https://doi.org/10.1680/geot.1999.49.2.231.
FHWA (Federal Highway Administration). 1984. Steel sheet piling design manual. Washington, DC: FHWA.
Fredlund, D. G. 2000. “The 1999 R.M. Hardy Lecture: The implementation of unsaturated soil mechanics into geotechnical engineering.” Can. Geotech. J. 37 (5): 963–986.
Fredlund, D. G., N. R. Morgenstern, and R. A. Widger. 1978. “The shear strength of unsaturated soils.” Can. Geotech. J. 15 (3): 313–321. https://doi.org/10.1139/t78-029.
Fredlund, D. G., and A. Xing. 1994. “Equations for the soil-water characteristic curve.” Can. Geotech. J. 31 (4): 521–532. https://doi.org/10.1139/t94-061.
Fredlund, D. G., A. Xing, and S. Huang. 1994. “Predicting the permeability function for unsaturated soils using the soil-water characteristic curve.” Can. Geotech. J. 31 (4): 533–546. https://doi.org/10.1139/t94-062.
GEO-SLOPE. 2017. Stress-strain modelling with GeoStudio. Calgary, AB, Canada: GEO-SLOPE Institution.
Gholampour, A., and A. Johari. 2019. “Reliability-based analysis of braced excavation in unsaturated soils considering conditional spatial variability.” Comput. Geotech. 115 (Nov): 103163. https://doi.org/10.1016/j.compgeo.2019.103163.
Goldberg, D. T., W. E. Jaworski, and M. D. Gordon. 1976. Lateral support systems and underpinning. Washington, DC: Federal Highway Administration.
Green, R. E., and J. C. Corey. 1971. “Calculation of hydraulic conductivity: A further evaluation of some predictive methods.” Soil Sci. Soc. Am. J. 35 (1): 3–8. https://doi.org/10.2136/sssaj1971.03615995003500010010x.
Hamid, T. B., and E. F. Tawfik. 2006. “Deep excavation retaining systems in unsaturated soils.” In Proc., 10th Int. Conf. on Piling and Deep Foundations, 135–143. Hawthorne, NJ: Deep Foundations Institute.
Han, J. Y., W. Zhao, Y. Chen, P. J. Jia, and Y. P. Guan. 2017. “Design analysis and observed performance of a tieback anchored pile wall in sand.” Math. Probl. Eng. 2017: 1–23. https://doi.org/10.1155/2017/8524078.
Han, Z. 2016. “Modelling stiffness and shear strength of compacted subgrade soils.” Ph.D. thesis, Dept. of Civil Engineering, Univ. of Ottawa.
Hardy, S., D. Nicholas, P. Ingram, A. Gaba, Y. Chen, and G. Biscontin. 2018. “New observational method framework for embedded walls.” Geotech. Res. 5 (3): 122–129. https://doi.org/10.1680/jgere.18.00013.
Houston, W. N., H. B. Dye, C. E. Zapata, Y. Y. Perera, and A. Harraz. 2006. “Determination of SWCC using one point suction measurement and standard curves.” In Proc., 4th Int. Conf. on Unsaturated Soils, 1482–1493. Reston, VA: ASCE.
Jennings, J. E. B., and J. B. Burland. 1962. “Limitations to the use of effective stresses in partly saturated soils.” Géotechnique 12 (2): 125–144. https://doi.org/10.1680/geot.1962.12.2.125.
Johari, A., and A. Gholampour. 2018. “A practical approach for reliability analysis of unsaturated slope by conditional random finite element method.” Comput. Geotech. 102 (Oct): 79–91. https://doi.org/10.1016/j.compgeo.2018.06.004.
Johari, A., and A. R. Kalantari. 2021. “System reliability analysis of soldier-piled excavation in unsaturated soil by combining random finite element and sequential compounding methods.” Bull. Eng. Geol. Environ. 80 (3): 2485–2507. https://doi.org/10.1007/s10064-020-02022-3.
Kaliampakos, D., A. Benardos, and A. Mavrikos. 2016. “A review on the economics of underground space utilization.” Tunnelling Underground Space Technol. 55 (May): 236–244. https://doi.org/10.1016/j.tust.2015.10.022.
Lambe, T. W. 1970. “Braced excavations.” In Proc., Specialty Conf. on Lateral Stresses in the Ground and Design of Earth Retaining Structures, 149–218. New York: ASCE.
Li, Z. W., and X. L. Yang. 2019. “Active earth pressure from unsaturated soils with different water levels.” Int. J. Geomech. 19 (7): 06019013. https://doi.org/10.1061/(ASCE)GM.1943-5622.0001471.
Luo, Z., Y. Li, S. Zhou, and H. Di. 2018. “Effects of vertical spatial variability on supported excavations in sands considering multiple geotechnical and structural failure modes.” Comput. Geotech. 95 (Mar): 16–29. https://doi.org/10.1016/j.compgeo.2017.11.017.
Mayor, P. A., S. M. Springman, and W. F. Morales. 2018. “Water retention curves of a dyke: In-situ vs laboratory determination.” In Proc., 7th Int. Conf. on Unsaturated Soils (UNSAT2018), 753–758. London: International Society for Soil Mechanics and Geotechnical Engineering.
Miller, G. A., N. K. Tan, R. W. Collins, and K. K. Muraleetharan. 2018. “Cone penetration testing in unsaturated soils.” Transp. Geotech. 17 (Dec): 85–99. https://doi.org/10.1016/j.trgeo.2018.09.008.
Ng, C. W. W., G. Zheng, J. Ni, and C. Zhou. 2020. “Use of unsaturated small-strain soil stiffness to the design of wall deflection and ground movement adjacent to deep excavation.” Comput. Geotech. 119 (Mar): 103375. https://doi.org/10.1016/j.compgeo.2019.103375.
Nguyen, V. H. 2013. “Influence of unloading soil modulus on horizontal deformation of diaphragm wall.” In Proc., Int. Symp. on New Technologies for Urban Safety of Mega Cities in Asia, 1247–1255. Tokyo: International Center for Urban Safety Engineering, Institute of Industrial Science.
NYSDOT (New York State DOT). 2013. Geotechnical design manual-Chapter 6: Engineering properties of soil and rock. New York: NYSDOT.
Oh, W. T., and S. Vanapalli. 2009. “A simple method to estimate the bearing capacity of unsaturated fine-grained soils.” In Proc., 62nd Canadian Geotechnical Conf., 234–241. Baghdad, Iraq: Ministry of Higher Education and Scientific Research.
Oh, W. T., and S. Vanapalli. 2011. “The relationship between the elastic and shear modulus of unsaturated soils.” In Proc., 5th Int. Conf. on Unsaturated Soils, 341–346. Boca Raton, FL: CRC Press.
O’Rourke, T. D. 1981. “Ground movements caused by braced excavations.” J. Geotech. Geoenviron. Eng. 107 (9): 1159–1178. https://doi.org/10.1061/AJGEB6.0001183.
Peck, R. B. 1969. “Deep excavations and tunneling in soft ground.” In Proc., 7th Int. Conf. on Soil Mechanics and Foundation Engineering. Mecanica, Mexico: Sociedad Mexicana de.
Pufahl, D. E., D. G. Fredlund, and H. Rahardjo. 1983. “Lateral earth pressures in expansive clay soils.” Can. Geotech. J. 20 (2): 228–241. https://doi.org/10.1139/t83-027.
Rassam, D. W., and F. Cook. 2002. “Predicting the shear strength envelope of unsaturated soils.” Geotech. Test. J. 25 (2): 215–220. https://doi.org/10.1520/GTJ11365J.
Russell, A., M. Pournaghiazar, and N. Khalili. 2010. “Interpreting CPT results in unsaturated sands.” In Proc., 2nd Int. Symp. on Cone Penetration Testing. Huntington Beach, CA: CPT’10 Organizing Committee.
Sarchenko, V. 2016. “The economic essence of underground development.” Procedia Eng. 165 (Jan): 134–145. https://doi.org/10.1016/j.proeng.2016.11.745.
Shwan, B. J. 2018. “Physical and numerical modelling of sheet pile wall for unsaturated sand.” In Proc., 7th Int. Conf. on Unsaturated Soils. London: International Society for Soil Mechanics and Geotechnical Engineering.
Simpson, B. 1992. “Retaining structures: Displacement and design.” Géotechnique 42 (4): 541–576. https://doi.org/10.1680/geot.1992.42.4.541.
Tavakkoli, N., and S. K. Vanapalli. 2011. “Rational approach for the design of retaining structures using the mechanics of unsaturated soils.” In Proc., 14th Pan-American Conf. on Soil Mechanics and Geotechnical Engineering. Richmond, BC, Canada: Canadian Geotechnical Society.
Taylor, O. D. S., L. A. Walshire, and W. W. Berry. 2020. “Reducing uncertainties and improving sand soil-water retention curve (SWRC) predictions for hazard screening analyses.” Can. Geotech. J. 57 (10): 1518–1533.
UN (United Nations), Department of Economic and Social Affairs, and Population Division. 2019. World urbanization prospects: The 2018 revision (ST/ESA/SER.A/420). New York: UN.
Vanapalli, S. K., and M. C. Catana. 2005. “Estimation of the SWCC of coarse-grained soils using one point measurement and simple properties.” In Proc., Int. Symp. on Advanced Experimental Unsaturated Soil Mechanics, 401–410. London: Taylor & Francis.
Vanapalli, S. K., D. G. Fredlund, D. E. Pufahl, and A. W. Clifton. 1996. “Model for the prediction of shear strength with respect to soil suction.” Can. Geotech. J. 33 (3): 379–392. https://doi.org/10.1139/t96-060.
Vanapalli, S. K., and F. Mohamed. 2013. “Bearing capacity and settlement of footings in unsaturated sand.” Int. J. GEOMATE 5 (9): 595–604. https://doi.org/10.21660/2013.9.3k.
Vanapalli, S. K., M. Sheikhtaheri, and W. T. Oh. 2018. “Experimental and simple semiempirical methods for interpreting the axial load versus settlement behaviors of single model piles in unsaturated sands.” Geotech. Test. J. 41 (4): 698–716. https://doi.org/10.1520/GTJ20170152.
van Genuchten, M. T. 1980. “A closed-form equation for predicting the hydraulic conductivity of unsaturated soils.” Soil Sci. Soc. Am. J. 44 (5): 892–898. https://doi.org/10.2136/sssaj1980.03615995004400050002x.
Vaz, C. M. P., M. de Freitas Iossi, J. de Mendonça Naime, Á. Macedo, J. M. Reichert, D. J. Reinert, and M. Cooper. 2005. “Validation of the Arya and Paris water retention model for Brazilian soils.” Soil Sci. Soc. Am. J. 69 (3): 577. https://doi.org/10.2136/sssaj2004.0104.
Wei, Y., X. Wu, J. Xia, G. A. Miller, C. Cai, Z. Guo, and A. Hassanikhah. 2019. “The effect of water content on the shear strength characteristics of granitic soils in South China.” Soil Tillage Res. 187 (Apr): 50–59. https://doi.org/10.1016/j.still.2018.11.013.
Wilson, G. W., D. G. Fredlund, and S. L. Barbour. 1997. “The effect of soil suction on evaporative fluxes from soil surfaces.” Can. Geotech. J. 34 (1): 145–155. https://doi.org/10.1139/t96-078.
WSP. 2018. Taking urban development underground. Montréal: WSP.
Yang, H., and A. Russell. 2015. “Cone penetration tests in unsaturated silty sands.” Can. Geotech. J. 53 (Sep): 431–444. https://doi.org/10.1139/cgj-2015-0142.
Yeow, H. C., D. Nicholson, C. L. Man, A. Ringer, P. Glass, and M. Black. 2014. “Application of observational method at Crossrail Tottenham court road station, UK.” Proc. Inst. Civ. Eng. Geotech. Eng. 167 (2): 182–193. https://doi.org/10.1680/geng.13.00035.
Information & Authors
Information
Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 148 • Issue 6 • June 2022
Copyright
© 2022 American Society of Civil Engineers.
History
Received: Nov 15, 2020
Accepted: Jan 13, 2022
Published online: Mar 24, 2022
Published in print: Jun 1, 2022
Discussion open until: Aug 24, 2022
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.
Cited by
- Marek Kopras, Wiesław Buczkowski, Anna Szymczak-Graczyk, Zbigniew Walczak, Sławomir Gogolik, Experimental Validation of Deflections of Temporary Excavation Support Plates with the Use of 3D Modelling, Materials, 10.3390/ma15144856, 15, 14, (4856), (2022).