Soil conditioning is an important stage in shield tunnel construction that can effectively improve muck flow plasticity, reduce cutter head wear and improve tunneling efficiency, especially in sandy and cobbly soils. The aim of this paper is to obtain the optimal ratio of residue modifiers in sandy and cobbly soil and to improve the equipment used in residue-related shield machines. Residual soil in a sandy pebble layer was selected, and particles with sizes over 50 mm were removed to form soil samples. Through laboratory tests, the optimal ratio of the modifier was obtained, and the shield tunneling machine equipment was optimized. The research results for the laboratory tests and equipment optimization were verified and adjusted appropriately through field tunneling tests. The following results were obtained. 1) A 3% foaming agent C was selected for the soil conditioning tests. The final mass ratio of the bentonite mixed solution of water, bentonite, soda ash (Na2CO3), and carboxymethyl cellulose (CMC) was 6:1:0.028:0.035. 2) Improving earth pressure balance (EPB) shield machine equipment can improve the effects of soil conditioning. 3) Compared with the volume of residual soil, the optimal ratio of soil conditioning in sandy and cobbly layer was 13% water, 4–5% bentonite mixed solution and 12–15% foam. In addition, the maximum ratio shall be taken for the strata with poor grain composition. These results can be used to provide excavation guidelines for using an EPB machine under these soil conditions.
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Borio L, Peila D (2010) Study of the permeability of roam conditioned soils with laboratory tests. American Journal of Environmental Sciences 6(4):365–370, DOI: https://doi.org/10.3844/ajessp.2010.365.370
Budach C, Thewes M (2015) Application ranges of EPB shields in coarse ground based on laboratory research. Tunneling and Underground Space Technology 50:296–304, DOI: https://doi.org/10.1016/j.tust.2015.08.006
GB50021-2001 (2009) Code for investigation of geotechnical engineering. Ministry of Construction of the People’s Republic of China, Beijing, China
Gharahbagh E, Rostami J, Talebi K (2014) Experimental study of the effect of conditioning on abrasive wear and torque requirement of full face tunneling machines. Tunneling and Underground Space Technology 41:127–136, DOI: https://doi.org/10.1016/j.tust.2013.12.003
He SH, Zhang SC, Li CH, Zhu ZP, Liu XB, Wang DH, Liu YP (2017) Blowout control during EPB shield tunnelling in sandy pebble stratum with high groundwater pressure. Chinese Journal of Geotechnical Engineering 39(9):1583–1590, DOI: https://doi.org/10.11779/CJGE201709005 (in Chinese)
Heisam H, Reza K (2019) Evaluation of the importance of gradually releasing stress around excavation regions in soil media and the effect of liners installation time on tunneling. Geotechnical and Geological Engineering 38(2):2213–2225, DOI: https://doi.org/10.1007/s10706-019-01158-8
Huang ZQ, Wang C, Dong JY, Zhou JJ, Yang JH, Li YW (2019a) Conditioning experiment on sand and cobble soil for shield tunneling. Tunneling and Underground Space Technology 87:187–194, DOI: https://doi.org/10.1016/j.tust.2019.02.011
Huang S, Wang SY, Xu CJ (2019b) Effect of grain gradation on the permeability characteristics of coarse-grained soil conditioned with foam for EPB shield tunneling. KSCE Journal of Civil Engineering 23(11):4662–4674, DOI: https://doi.org/10.1007/s12205-019-0717-7
Jiang HT, Gong QM, Du XL (2013) Experimental study on soil conditioning in cobble layer by use of earth pressure balanced machine. Chinese Journal of Geotechnical Engineering 35(2):284–292 (in Chinese)
Milligan G (2000) Lubrication and soil conditioning in tunneling, pipe jacking and micro tunneling. Geotechnical Consulting Group, London, UK, 4–10
Mori L, Mooney M, Cha M (2018) Characterizing the influence of stress on foam conditioned sand for EPB tunneling. Tunneling and Underground Space Technology 71:454–465, DOI: https://doi.org/10.1016/j.tust.2017.09.018
Peila D (2014) Soil conditioning for EPB shield tunnelling. KSCE Journal of Civil Engineering 18(4):831–836, DOI: https://doi.org/10.1007/s12205-014-0023-3
Peila D, Oggeri C, Borio L (2009) Using the slump test to assess the behavior of conditioned soil for EPB tunneling. Environmental and Engineering Geoscience 15(3):167–174, DOI: https://doi.org/10.2113/gseegeosci.15.3.167
Peila D, Oggeri C, Vinai R (2007) Screw conveyor device for laboratory tests on conditioned soil for EPB tunneling operations. Journal of Geotechnical and Geoenvironmental Engineering 133(12):1622–1625, DOI: https://doi.org/10.1061/(ASCE)1090-0241(2007)133:12(1622)
Quebaud S, Sibai M, Henry J (1998) Use of chemical foam for improvements in drilling by earth-pressure-balanced shields in granular soils. Tunneling and Underground Space Technology 13(2):173–180, DOI: https://doi.org/10.1016/S0886-7798(98)00045-5
Thewes M, Budach C, Bezuijen A (2012) Foam conditioning in EPB tunneling. Proceedings of the 7th international symposium on geotechnical aspects of underground construction in soft ground, May 17–19, Rome, Italy
Vinai R, Oggeri C, Peila D (2007) Soil conditioning of sand for EPB applications: A laboratory research. Tunneling and Underground Space Technology 23:308–317, DOI: https://doi.org/10.1016/j.tust.2007.04.010
Wang GF (2009) Soil conditioning technologies and implementation for EPB shield in Beijing subway. Modern Tunnelling Technology 46(4):74–82 (in Chinese)
Wang SY, Hu QX, Wang HB, Huang S, Ye F, Liu PF (2020) Study on permeability characteristics of the shield foam conditioned sand under influence of flow plasticity and water pressure. China Journal of Highway and Transport 33(2):94–102, DOI: https://doi.org/10.19721/j.cnki.1001-7372.2020.02.009 (in Chinese)
Wei YJ, Wang DL, Li JG, Jie YX (2020) Effects of soil conditioning on characteristics of a clay-sand-gravel mixed soil based on laboratory test. Applied Sciences 10(3300):1–16, DOI: https://doi.org/10.3390/app10093300
Williamson GE, Traylor MT, Higuchi M (1999) Soil conditioning for EPB shield tunneling on the south bay ocean outfall. Proceedings of rapid exaction and tunneling conference, June 21–23, Orland, FL, USA
Wilms J (1995) Influence of properties of the support medium on the wear of EPB-shields. MSc Thesis, University of Duisburg-essen, Duisburg, Germany
Wu YL, Ali N, Meng FY, Michael M (2020) Experimental study on the stability of foam-conditioned sand under pressure in the EPBM chamber. Tunneling and Underground Space Technology 106:1–12, DOI: https://doi.org/10.1016/j.tust.2020.103590
Yan X, Gong Q, Jiang H (2010) Soil conditioning for earth-pressure balanced shields excavation in sand layers. Chinese Journal of Underground Space and Engineering 6(3):449–453 (in Chinese)
Zhou JX (2019) Experimental study of soil conditioning with foam for the shield tunnel in composite stratum. Modern Tunnelling Technology 29(4):194–199, DOI: https://doi.org/10.13807/j.cnki.mtt.2019.04.029 (in Chinese)
The project presented in this article is supported by the Scientific and Technological Innovation Project of Excellent Talents in Shanxi Province, grant number 201605D211037.
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Zhen, Z., Ge, X. & Zhang, J. Soil Conditioning Tests on Sandy and Cobbly Soil for Shield Tunneling. KSCE J Civ Eng (2021). https://doi.org/10.1007/s12205-021-0921-0
- Shield tunnel
- Sandy and cobbly soil
- Soil conditioning
- Laboratory tests
- Field tests