Experimental study and engineering application of slurry permeability mechanism of slurry shield in circular-gravel stra
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ORIGINAL PAPER
Experimental study and engineering application of slurry permeability mechanism of slurry shield in circular-gravel stratum Dongshuang Liu 1 & Xinrong Liu 1,2 Qiang Chen 1 & Chengxian Weng 4
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& Chengqian Lin & Fei Xiong & Yafeng Han & Qingjun Meng & Zuliang Zhong
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Received: 19 May 2020 / Accepted: 16 July 2020 # Saudi Society for Geosciences 2020
Abstract The key to maintain the stability of the excavation face of slurry shield in the construction of high-permeability circular-gravel stratum is the film-forming quality of slurry. Taking the use of slurry shield in the construction of Nanning Metro in circulargravel stratum as a case, and with the help of self-designed slurry permeation device, this paper carries out the permeation filmforming experiments of different ratios of slurry in circular-gravel stratum to study the effects of slurry specific gravity, viscosity, and grouting pressure on amount of infiltrated water, film-forming time, and slurry film shape and carries out a verification at the construction site. The conclusions are as follows: slurry specific gravity increases linearly with the content of clay, and the viscosity increases linearly with the content of CMC. The higher the slurry specific gravity is, the better the film quality is. The higher the slurry viscosity is, the earlier the slurry film is formed and the smaller the amount of water infiltrated from slurry is. The effect of slurry specific gravity on the amount of infiltrated water is greater than that of viscosity. The field verification results show that when the slurry density is 1.07 g/cm3, the slurry film has been basically formed, and when the mud density is 1.15 g/cm3, the slurry film has been formed completely. When the slurry viscosity increases from 24 to 33 s, the liquid level of the air cushion chamber and the number of air compressors change slightly. When the water loss of the slurry is 14 s, the slurry level of the sedimentation tank changes slightly, and slurry loss is effectively controlled; when the viscosity of the slurry increases and cause water loss to reaches 12 s, the viscosity of the slurry achieves the optimal effect. This study can provide reference for studies of similar projects in the future. Keywords Circular-gravel stratum . Shield . Slurry permeation . Field verification
Introduction In slurry shield, slurry plays a role in stabilizing excavation face and deslagging (Yin et al. 2016; Fritz 2007; Min et al. 2013; Li et al. 2009). A key factor determining whether the shield machine can tunnel smoothly in the stratum lies in the permeability of the slurry and the quality of the film (Min et al. 2010; Alem et al. 2013; Lee and Koplik 2001; Lee and Lee 2011; Tong and Johnaon 2006). Slurry properties are
related to composition and corresponding ratio. In this regard, many scholars have done a lot of valuable research. Through the mud film formation test in the high permeability formation, Watanabe and Yamazaki (Watanabe and Yamazaki 1981) found that the increase of mud dens
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