A column system for modeling bentonite slurry infiltration in sands

• Published in: Journal of Zhejiang University. A. Science Vol. 17; no. 10; pp. 818 - 827
• Main Authors: Yin, Xin-sheng, Chen, Ren-peng, Li, Yu-chao, Qi, Shuai
• Format: Journal Article
• Language: English
• Published: Hangzhou Zhejiang University Press 01.10.2016; Springer Nature B.V
• Subjects: Bentonite; cake; Civil Engineering; Classical and Continuum Physics; column; conductivity; Diameters; Electrical conductivity; Electrical resistivity; Engineering; Excavation; Filter; Filter cake; Hydraulic; Industrial Chemistry/Chemical Engineering; Infiltration; Leachates; Mechanical Engineering; penetration; Reservoirs; Sand; Sandy soils; shield; Slurries; Slurry; Slurry infiltration; Soil permeability; Transducers; Tunneling; Tunneling shield; 泥浆渗透; Slurry penetration; 渗透柱; Infiltration column; Hydraulic conductivity; 隧道盾构; 泥膜; 渗透系数; Filter cake
• ISSN: 1673-565X; 1862-1775
• DOI: 10.1631/jzus.A1500290

Pressurized bentonite slurry is applied on a tunnel face to form a filter cake to stabilize the tunnel face when the slurryshield excavates through the sandy soil. Failure of the tunnel face may be caused by a high permeable filter cake, which commonlyhas a long penetration distance of slurry in sands. A column system with a height of 680 mm and a diameter of 300 mm was de-veloped to model pressurized slurry infiltration in sands. Pressure transducers were installed to estimate the hydraulic conductivityof the filter cake during slurry infiltration. The electrical conductivity of the leachate of collected samples was measured. Resultsshow that the majority of fine particles in slurry are within the range 100-300 mm into the sand specimen. The time for forming animpermeable filter cake is about 300 s, which indicates the impermeable filter cake is hard to form during the excavation.