Soil conditioning in EPB shield tunnelling – An overview of laboratory tests

Peila, Daniele; Martinelli, Daniele; Todaro, Carmine; Luciani, Andrea

doi:10.1002/geot.201900021

Cited by 28 publications

(7 citation statements)

References 36 publications

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“…Four foaming agent products (P1, P2, P3 and P4, equally suitable from a geotechnical point of view for this tunnel excavation) to be used for the two lithologies were suggested by the geotechnical laboratory feasibility studies with slump cone tests. These tests evaluated the workability and consistency of the two soils with the various foaming agents, providing the correct foaming agent treatment ratio (TR) to be applied for each soil [19][20][21]33]. The tests were conducted at Turin Polytechnic (Environment, Land and Infrastructure Engineering Dept., Tunnelling and Underground Space Lab), using a foam generation system that reproduces the conditioning characteristics used by an EPB-TBM [19,34].…”

Section: Soils and Foaming Agentsmentioning

confidence: 99%

“…These tests evaluated the workability and consistency of the two soils with the various foaming agents, providing the correct foaming agent treatment ratio (TR) to be applied for each soil [19][20][21]33]. The tests were conducted at Turin Polytechnic (Environment, Land and Infrastructure Engineering Dept., Tunnelling and Underground Space Lab), using a foam generation system that reproduces the conditioning characteristics used by an EPB-TBM [19,34]. Table 1 reports the density of each foaming agent and the highest amount used (soil Treatment Ratio, TR, L/m 3 ) [19], together with the percentage of SLES.…”

Section: Soils and Foaming Agentsmentioning

confidence: 99%

“…The tests were conducted at Turin Polytechnic (Environment, Land and Infrastructure Engineering Dept., Tunnelling and Underground Space Lab), using a foam generation system that reproduces the conditioning characteristics used by an EPB-TBM [19,34]. Table 1 reports the density of each foaming agent and the highest amount used (soil Treatment Ratio, TR, L/m 3 ) [19], together with the percentage of SLES. For the SIL lithology, in one case P3 was used together with P4 to improve the soil workability [18].…”

Section: Soils and Foaming Agentsmentioning

confidence: 99%

“…The use of commercial products (foaming agents) is necessary in mechanized tunnelling with Earth Pressure Balance-Tunnel Boring Machines (EPB-TBMs) [18][19][20][21][22]. The spoil material coming out of the machine can be maintained at temporary deposits.…”

Section: Introductionmentioning

confidence: 99%

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Mesocosm Experiments at a Tunnelling Construction Site for Assessing Re-Use of Spoil Material as a By-Product

Caracciolo

Grenni

Mariani

et al. 2021

Water

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Mechanized excavation of tunnels with Earth Pressure Balance-Tunnel Boring Machines requires the use of foaming agents. The latter contain the anionic surfactant sodium lauryl ether sulphate (SLES) as the main compound. The re-use as a by-product of excavated soil containing foaming agents (spoil material) can pose a risk for soil and particularly for aquatic ecosystems if they are close to the spoil material final destination site. This work reports the chemical results (SLES residual concentrations) and ecotoxicological effects (battery of five tests) of 28 day-mesocosm studies performed at a tunnelling construction site. The soil mesocosms were set up with two different lithologies, which contained four different foaming agent products at the highest amounts used for excavation. The decrease in SLES concentrations and the ecotoxicological tests were performed in soil and its water extract (elutriate) at different times (0, 7, 14, 28 d). Elutriates were prepared in order to simulate a possible SLES leaching from soil to water. The results showed a decrease in SLES over time and different ecotoxicological responses depending not only on the initial amount of each product, but also on the soil lithology and organism tested (aquatic or terrestrial). This study showed how only site-specific ecotoxicological evaluations can ensure a safe management of the spoil material, making possible the re-use of soil and avoiding production of waste.

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Section: Soils and Foaming Agentsmentioning

confidence: 99%

Section: Soils and Foaming Agentsmentioning

confidence: 99%

Section: Soils and Foaming Agentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Mesocosm Experiments at a Tunnelling Construction Site for Assessing Re-Use of Spoil Material as a By-Product

Caracciolo

Grenni

Mariani

et al. 2021

Water

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“…The workability is widely studied by slump tests to ensure the effect of soil conditioning (Peila et al, 2013;Peila et al, 2016;Peila et al, 2019). Yet in cohesive soil, slump test is not feasible as the soil is usually in a plastic state (Oliveira, 2018;Oliveira et al, 2019), the consistency index I c is used instead.…”

Section: Introductionmentioning

confidence: 99%

Experimental study and field validation on soil clogging of EPB shields in completely decomposed granite

Chen

Bezuijen

Fang

et al. 2022

Tunnelling and Underground Space Technology

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Clogging may occur inside the shield machine during earth pressure balance (EPB) tunnelling in cohesive soils. Soil conditioning can be used to reduce clogging potential and ensure the efficiency of the shield tunnelling. The current methods used to assess the clogging potential mainly focus on pure clayey soils or artificial mixed soils, the clogging in natural weathered soils is less studied. This paper studied the clogging when tunnelling in completely decomposed granite by laboratory tests, followed by field validation. In the laboratory tests, the torque and excavation speed were recorded and the soil distribution on the cutting device were analyzed. It appeared that when clogging happens, the excavation speed drops and the fluctuation in speed increases, while the torque rises as well as the fluctuations in the torque. Clogging first covers the cutters, then fill in the intervals between cutters, and finally blocked the openings on the cutting device. The opening at the central part of cutting device is of vital importance to prevent clogging. The process of clogging can be divided into three stages, the initial stage, the stabilized stage and the clogging stage. In-situ data from Guangzhou Metro Line 21 showed that clogging on cutterhead was effectively avoided when using the recommended soil conditioning scheme. Furthermore, the clogging evaluation method and process of clogging proposed are consistent with field validation and with current major clogging assessment method.

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Evaluation of foam application in providing required conditioning for EPB hard rock TBMs

Firouzei

Hassanpour

Peila

et al. 2023

Geomechanics and Tunnelling

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Utilizing the earth pressure balancing technique on hard rock tunnel boring machines (TBMs) is an efficient way to overcome engineering geological hazards that disrupt the application of these machines. Considering that geomechanical and engineering geological conditions of soil and rock are dramatically different, proposing a suitable conditioning design for earth pressure balance (EPB) hard rock TBMs requires particular attention to the characteristics of the excavated material and ground conditions. In this paper, foam application providing a favourable support medium for EPB hard rock TBMs is evaluated based on the experience of the Tehran metro line 6 southern expansion sector project, using laboratory and actual data. TBM muck, with different water contents, was used as the test specimen after granulometry correction. The trend of changes in the workability of foam conditioned mix was obtained by performing 350 slump tests. The pressurized permeability cell test (PPCT), a testing device capable of applying high water pressures to the conditioned material, was used to evaluate the impermeability of workable mixes. Results indicate that although foam can efficiently increase the workability of dry and moistened specimens, the presence of a separated liquid phase in the test specimen disrupts its application; moreover, foam conditioned mix is permeable even against low water pressures.

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Soil conditioning in EPB shield tunnelling – An overview of laboratory tests

Cited by 28 publications

References 36 publications

Mesocosm Experiments at a Tunnelling Construction Site for Assessing Re-Use of Spoil Material as a By-Product

Mesocosm Experiments at a Tunnelling Construction Site for Assessing Re-Use of Spoil Material as a By-Product

Experimental study and field validation on soil clogging of EPB shields in completely decomposed granite

Evaluation of foam application in providing required conditioning for EPB hard rock TBMs

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