JRMGE / Vol 16 / Issue 2
Experimental study on workability and permeability of sandy soils conditioned with thickened foam
Zhiyao Feng, Shuying Wang, Tongming Qu, Xiangcou Zheng, Fanlin Ling
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a School of Civil Engineering, Central South University, Changsha, 410075, China
b Tunnel and Underground Engineering Research Center, Central South University, Changsha, 410075, China
c Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, 999077, Hong Kong, China
d Geo-Engineering Section, Delft University of Technology, Delft, 999025, Netherlands
2024, 16(2): 532-544. doi:10.1016/j.jrmge.2023.05.015
Received: 2022-12-07 / Revised: 2023-04-10 / Accepted: 2023-05-15 / Available online: 2023-08-25
2024, 16(2): 532-544.
doi:10.1016/j.jrmge.2023.05.015
Received: 2022-12-07
Revised: 2023-04-10
Accepted: 2023-05-15
Available online: 2023-08-25
Water spewing and muck plugging often occur during earth pressure balance (EPB) shield machines tunnelling in water-rich sandy strata, even though the conventional foam has been employed to condition sandy soils. In this study, a novel thickened foaming agent suitable for EPB shield tunnelling in water-rich sandy strata is developed. In contrast to conventional foam-conditioned sands, the thickened foam-conditioned sand has a low permeability due to the consistent filling of soil pores with the thickened foam, and the initial permeability coefficient decreases by approximately two orders of magnitude. It also exhibits a suitable workability, which is attributed to the enhanced capability of the thickened foam to condition sandy soils. In addition, the effect of concentration on the stability of the foam is explained by the Gibbs-Marangoni effect, and conditioning mechanisms for the thickened foam on sands are discussed from the evolution of foam bubbles.
Keywords: Earth pressure balance (EPB) shield, Thickened foam, Foam-conditioned sand, Permeability, Workability
Article Data
Author(s) Information
Zhiyao Feng
Zhiyao Feng obtained his MEng degree in Civil Engineering from University of Science and Technology Beijing, China, in 2020, and he is currently the PhD Candidate of Central South University, Changsha, China. He has participated in several shield tunnel (EPB) or TBM projects, such as Longquan water tunnel in the Dianzhong Water Diversion Project of China, Gaoligongshan Tunnel, and Beijing Subway Line 17. His research interests include (1) mechanism of soil conditioning for EPB shield tunnels and efficient intelligent excavation technology; and (2) mechanical behavior and safety control technology of tunnels under complex conditions.