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Indexed by:期刊论文

Date of Publication:2011-09-01

Journal:JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY

Included Journals:Scopus、SCIE、EI

Volume:25

Issue:9

Page Number:2259-2266

ISSN No.:1738-494X

Key Words:Conditioned sands; Rheology; Viscoplastic parameters; Earth pressure balance shield machine

Abstract:A device was developed to determine the viscoplastic parameters of conditioned soil, which works on the principle of torsional shear applied to a standard vane with controlled strain rate. Rheological measurements were taken for three sand samples with the same bentonite slurry injection ratio (14.3%), but with different foam injection ratios (19%, 23%, and 27%), by changing the gasbag pressure levels (i.e., 0, 100, 200, 300, and 400 kPa) and vane speeds (i.e., 1/3.4, 1/4.1, 1/5, 1/6.4, 1/9, 1/15, and 1/30 RPM) to determine the effects of confining pressure and foam injection ratio on the viscoplastic parameters. The results show that the values of viscosity coefficient and yield stress for conditioned sands are in the range of 9.1-53.5 kPa.s and 1.5-10.2 kPa, respectively. The viscoplastic parameters increase with the increase of the confining pressure, and decrease with the increase of the foam injection ratio for all tested samples.