scholarly journals Micromechanical study of soil conditioning on Sandy Stratum for an EPB Shield

2021 ◽  
Vol 2021 (1) ◽  
pp. 012050
Author(s):  
Yanjie Ding
Keyword(s):  
Soil Conditioning ◽  
Epb Shield

scholarly journals Application Ranges of EPB Shield TBM in Weathered Granite Soil: A Laboratory Scale Study

2021 ◽  
Vol 11 (7) ◽  
pp. 2995
Author(s):  
Tae-Hwan Kim ◽  
In-Mo Lee ◽  
Hee-Young Chung ◽  
Jeong-Jun Park ◽  
Young-Moo Ryu
Keyword(s):  
Water Content ◽  
Upper And Lower Bounds ◽  
Shield Tunnel ◽  
Particle Crushing ◽  
Pressure Balance ◽  
Soil Conditioning ◽  
Weathered Granite ◽  
Weathered Granite Soil ◽  
Granite Soil ◽  
Epb Shield

Soil conditioning is a key factor in increasing tunnel face stability and extraction efficiency of excavated soil when excavating tunnels using an earth pressure balance (EPB) shield tunnel boring machine (TBM). Weathered granite soil, which is abundant in the Korean Peninsula (also in Japan, Hong Kong, and Singapore), has different characteristics than sand and clay; it also has particle-crushing characteristics. Conditioning agents were mixed with weathered granite soils of different individual particle-size gradations, and three characteristics (workability, permeability, and compressibility) were evaluated to find an optimal conditioning method. The lower and upper bounds of the water content that are needed for a well-functioning EPB shield TBM were also proposed. Through a trial-and-error experimental analysis, it was confirmed that soil conditioning using foam only was possible when the water content was controlled within the allowable range, that is, between the upper and lower bounds; when water content exceeded the upper bound, soil conditioning with solidification agents was needed along with foam. By taking advantage of the particle-crushing characteristics of the weathered granite soil, it was feasible to adopt the EPB shield TBM even when the soil was extremely coarse and cohesionless by conditioning with polymer slurries along with foam. Finally, the application ranges of EPB shield TBM in weathered granite soil were proposed; the newly proposed ranges are wider and expanded to coarser zones compared with those proposed so far.

Soil Conditioning for EPB Shield Tunneling in Silty Clay and Weathered Mudstone

2021 ◽  
Vol 21 (9) ◽  
pp. 06021020
Author(s):  
Zeen Wan ◽  
Shuchen Li ◽  
Chao Yuan ◽  
Shisen Zhao ◽  
Manling Wang ◽  
...  
Keyword(s):  
Silty Clay ◽  
Shield Tunneling ◽  
Soil Conditioning ◽  
Epb Shield

Soil Conditioning for EPB Shield Tunneling in Argillaceous Siltstone with High Content of Clay Minerals: Case Study

2017 ◽  
Vol 17 (4) ◽  
pp. 05016002 ◽  
Author(s):  
Xinyu Ye ◽  
Shuying Wang ◽  
Junsheng Yang ◽  
Daichao Sheng ◽  
Chao Xiao
Keyword(s):  
Clay Minerals ◽  
Shield Tunneling ◽  
Soil Conditioning ◽  
Argillaceous Siltstone ◽  
Epb Shield

scholarly journals Experimental Study on the Soil Conditioning Materials for EPB Shield Tunneling in Silty Sand

2020 ◽  
Vol 2020 ◽  
pp. 1-21
Author(s):  
Chi-Hao Cheng ◽  
Shao-Ming Liao ◽  
Xiao-Bo Huo ◽  
Li-Sheng Chen
Keyword(s):  
Earth Pressure ◽  
Test System ◽  
Cutting Performance ◽  
Silty Sand ◽  
Test Results ◽  
Pressure Balance ◽  
Shield Tunneling ◽  
Soil Conditioning ◽  
Sand Stratum ◽  
Epb Shield

Earth pressure balance (EPB) shield tunneling in a silty sand stratum is frequently faced with the wear of rotary cutter disc, clogging, or even collapse of workface due to its noncohesive and discrete properties of silty sand material. Soil conditioning is an effective way to reduce the discrete and friction properties of silty sand and to increase its rheology and fluidity, thus improving the cutting performance of EPB machines. However, soil conditioning materials were generally prepared and injected based on past limited field experiences or lab tests which were far from reality. In this article, a ground suitability test system for simulating shield tunneling in a conditioned ground was specially developed and used in a series of tests to investigate the influences of key factors of soil conditioning on the shield cutting performance. In addition, a field experiment of shield tunneling in silty sand of Wuhan Metro was conducted for verification. The major findings were obtained as follows. (1) The proposed test system performed well in simulating and assessing the cutting performance of EPB shield in conditioned soils, and the test results agreed well with the field test. (2) The soil conditioning materials can significantly reduce the cutting torque of shield tunneling in silty sand by up to 60%–70%. (3) The optimal foam and slurry parameters are suggested in the paper for shield tunneling in silty sand, respectively. (4) The test results reveal that the slurry conditioning is better than the foam in decreasing the cutter torque in silty sand. To achieve the same effect of soil conditioning, the injection ratios of foam and slurry should be 45% and 10%, respectively, to achieve the torque reduction ratio of 60%. These findings can provide a practical reference for engineers to determine the best-fit conditioning materials and construction parameters in the silty sand stratum.

Soil Conditioning of Weathered Granite Soil used for EPB Shield TBM: A Laboratory Scale Study

2019 ◽  
Vol 23 (4) ◽  
pp. 1829-1838 ◽  
Author(s):  
Tae-Hwan Kim ◽  
Byung-Kyu Kim ◽  
Kang-Hyun Lee ◽  
In-Mo Lee
Keyword(s):  
Laboratory Scale ◽  
Soil Conditioning ◽  
Weathered Granite ◽  
Weathered Granite Soil ◽  
Granite Soil ◽  
Epb Shield

Soil conditioning in EPB shield tunnelling – An overview of laboratory tests

2019 ◽  
Vol 12 (5) ◽  
pp. 491-498 ◽  
Author(s):  
Daniele Peila ◽  
Daniele Martinelli ◽  
Carmine Todaro ◽  
Andrea Luciani
Keyword(s):  
Laboratory Tests ◽  
Soil Conditioning ◽  
Shield Tunnelling ◽  
Epb Shield
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