Pore pressure measurements in saturated sand in front of an approaching EPB and laboratory investigations

This paper presents measurements of total pressures and pore pressures in the mixing chamber, the pore pressures in the soil in front of an earth pressure balance (EPB) at the Botlek Rail tunnel, as well as laboratory tests on foam infiltration behavior from foam–sand mixture to saturated sand. It s...

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Bibliographic Details
Published in:Acta geotechnica 2024-06, Vol.19 (6), p.4055-4068
Main Authors: Zheng, Dongzhu, Bezuijen, Adam
Format: Article
Language:English
Subjects:
Chambers
Complex Fluids and Microfluidics
Drilling
Earth pressure
Engineering
Foundations
Geoengineering
Geotechnical Engineering & Applied Earth Sciences
Groundwater
Groundwater flow
Hydraulics
Infiltration
Laboratories
Laboratory tests
Permeability
Pore pressure
Pore water pressure
Railway tunnels
Research Paper
Sand
Slurries
Soft and Granular Matter
Soil
Soil permeability
Soil Science & Conservation
Solid Mechanics
Tests
Tunnels
Water flow
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Summary:This paper presents measurements of total pressures and pore pressures in the mixing chamber, the pore pressures in the soil in front of an earth pressure balance (EPB) at the Botlek Rail tunnel, as well as laboratory tests on foam infiltration behavior from foam–sand mixture to saturated sand. It shows that the plastering effect at the tunnel face is less effective for an EPB shield than for a slurry shield, as the pressure fluctuations are greater in the mixing chamber for an EPB shield, suggesting a higher water leakage at the tunnel face. The difference in the development of excess pore pressure at two different locations of the EPB shield suggests the influence of the soil permeability. Foam infiltration at the tunnel face can result in a low permeable layer that restricts the ground water flow. Results from laboratory tests suggest that foam infiltration will be influenced by foam injection ratio and soil permeability. As the foam infiltration length is only limited, no low permeable layer can be formed during drilling for fine sand conditions. While a larger foam infiltration length can be expected for medium sand condition. Field measurements on the development of pore pressures in the soils at the two different locations show agreement with the conclusions from laboratory tests.
ISSN:1861-1125
1861-1133
DOI:10.1007/s11440-023-02139-1