Effects of flocculants on in–situ recycling potential of waste EPB shield muck with residual foams
The in–situ recycling technique offers a promising solution for the efficient management of the escalating volumes of waste muck or slurry generated during shield tunneling. While foam is extensively utilized for soil conditioning in earth pressure balance (EPB) tunneling, the effects of organic and...
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| Language: | English |
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Elsevier
2025-06-01
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| Series: | Soils and Foundations |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S0038080625000599 |
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| author | Yao Lu Ming Huang Jim S. Shiau Fengwen Lai Liqian Peng |
| author_facet | Yao Lu Ming Huang Jim S. Shiau Fengwen Lai Liqian Peng |
| author_sort | Yao Lu |
| collection | DOAJ |
| description | The in–situ recycling technique offers a promising solution for the efficient management of the escalating volumes of waste muck or slurry generated during shield tunneling. While foam is extensively utilized for soil conditioning in earth pressure balance (EPB) tunneling, the effects of organic and inorganic flocculants on the in–situ recycling potential of waste EPB shield muck containing residual foams remain underexplored. To bridge this gap, laboratory experiments were conducted using four flocculants: cationic polyacrylamide (CPAM), nonionic polyacrylamide (NPAM), anionic polyacrylamide (APAM), and polyaluminum chloride (PACL), with an enhanced flocculation and press–filtration apparatus. The defoaming–flocculation–dewatering behavior of waste EPB shield muck was systematically investigated by evaluating key parameters, including residual foam height, defoaming ratio, antifoaming ratio, total suspended solids, turbidity, moisture content, and zeta potential, while accounting for both muck dry mass and fines content. Moreover, the microscopic structure of flocculates and filter cakes was characterized using nanoparticle size analysis and scanning electron microscopy. The experimental results reveal that CPAM exhibits constrained flocculation and dewatering efficiency, primarily attributed to diminished charge neutralization resulting from residual anionic surfactants. In contrast, PACL demonstrates superior dewatering performance compared to NPAM and APAM, but exhibits the lowest flocculation and foam–suppression efficiency. Additionally, a consistent linear negative correlation is identified between the flocculation and dewatering indices of EPB shield muck, independent of the flocculant type, whether organic or inorganic. |
| format | Article |
| id | doaj-art-07d6e36b30c5442d92f2e29c70cf8fec |
| institution | Kabale University |
| issn | 2524-1788 |
| language | English |
| publishDate | 2025-06-01 |
| publisher | Elsevier |
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| series | Soils and Foundations |
| spelling | doaj-art-07d6e36b30c5442d92f2e29c70cf8fec2025-08-20T03:29:10ZengElsevierSoils and Foundations2524-17882025-06-0165310162510.1016/j.sandf.2025.101625Effects of flocculants on in–situ recycling potential of waste EPB shield muck with residual foamsYao Lu0Ming Huang1Jim S. Shiau2Fengwen Lai3Liqian Peng4School of Civil Engineering, Fuzhou University, Fuzhou 350108, ChinaSchool of Civil Engineering, Fuzhou University, Fuzhou 350108, China; Corresponding author.School of Engineering, University of Southern Queensland, Toowoomba 4350, AustraliaSchool of Civil Engineering, Fuzhou University, Fuzhou 350108, ChinaChina Railway 18th Bureau Group First Engineering Co., Ltd, Baoding 072750, ChinaThe in–situ recycling technique offers a promising solution for the efficient management of the escalating volumes of waste muck or slurry generated during shield tunneling. While foam is extensively utilized for soil conditioning in earth pressure balance (EPB) tunneling, the effects of organic and inorganic flocculants on the in–situ recycling potential of waste EPB shield muck containing residual foams remain underexplored. To bridge this gap, laboratory experiments were conducted using four flocculants: cationic polyacrylamide (CPAM), nonionic polyacrylamide (NPAM), anionic polyacrylamide (APAM), and polyaluminum chloride (PACL), with an enhanced flocculation and press–filtration apparatus. The defoaming–flocculation–dewatering behavior of waste EPB shield muck was systematically investigated by evaluating key parameters, including residual foam height, defoaming ratio, antifoaming ratio, total suspended solids, turbidity, moisture content, and zeta potential, while accounting for both muck dry mass and fines content. Moreover, the microscopic structure of flocculates and filter cakes was characterized using nanoparticle size analysis and scanning electron microscopy. The experimental results reveal that CPAM exhibits constrained flocculation and dewatering efficiency, primarily attributed to diminished charge neutralization resulting from residual anionic surfactants. In contrast, PACL demonstrates superior dewatering performance compared to NPAM and APAM, but exhibits the lowest flocculation and foam–suppression efficiency. Additionally, a consistent linear negative correlation is identified between the flocculation and dewatering indices of EPB shield muck, independent of the flocculant type, whether organic or inorganic.http://www.sciencedirect.com/science/article/pii/S0038080625000599EPB shieldFlocculantIn–situ recyclingResidual foamWaste muck |
| spellingShingle | Yao Lu Ming Huang Jim S. Shiau Fengwen Lai Liqian Peng Effects of flocculants on in–situ recycling potential of waste EPB shield muck with residual foams Soils and Foundations EPB shield Flocculant In–situ recycling Residual foam Waste muck |
| title | Effects of flocculants on in–situ recycling potential of waste EPB shield muck with residual foams |
| title_full | Effects of flocculants on in–situ recycling potential of waste EPB shield muck with residual foams |
| title_fullStr | Effects of flocculants on in–situ recycling potential of waste EPB shield muck with residual foams |
| title_full_unstemmed | Effects of flocculants on in–situ recycling potential of waste EPB shield muck with residual foams |
| title_short | Effects of flocculants on in–situ recycling potential of waste EPB shield muck with residual foams |
| title_sort | effects of flocculants on in situ recycling potential of waste epb shield muck with residual foams |
| topic | EPB shield Flocculant In–situ recycling Residual foam Waste muck |
| url | http://www.sciencedirect.com/science/article/pii/S0038080625000599 |
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