The New Bubble-Slurry for Sand Conditioning during EPB Shield Tunnelling: A Laboratory Scale Study.

Autor: Wang, Lu, Zhu, Wei, Qian, Yongjin, Xing, Huitang
Zdroj: KSCE Journal of Civil Engineering; May2023, Vol. 27 Issue 5, p2191-2201, 11p
Abstrakt: Spewing is a key issue during earth pressure balance (EPB) shield tunneling in a water-rich sandy stratum. This paper proposed the bubble-slurry as a new type of soil conditioning agent. The foamability and stability of the bubble-slurry were studied, and the volume stability, fluidity, and permeability of bubble-slurry-conditioned sands with hydraulic gradient of 2 to 10 were analyzed. The stability mechanism was explored by the zeta potential and microstructure of the bubble-slurry system. The formulation of bubble-slurry with a half-life of 121–383 h was determined through laboratory tests. The results of soil conditioning experiments showed that the bubble-slurry-conditioned soil exhibited appropriate fluidity, excellent volume stability and low permeability in a certain period. The use of bubble-slurry can save approximately 3.0–8.2% of the slurry consumption compared with the method of slurry conditioning. The zeta potential and the distribution of slurry particles of the bubble-slurry system were key mechanisms affecting the stability of the bubble-slurry. The high absolute value of zeta potential of the system increases the dispersion of bubbles, and the slurry particles uniformly distributed on the bubble liquid film and in the Plateau boundary are conducive to enhancing the anti-disturbance ability and inhibiting the decay of bubbles. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index