Preparation and engineering properties of alkali-activated filling grouts for shield tunnel

Song, Wei; Zhu, Zhiduo; Pu, Shaoyun; Wan, Yu; Huo, Wangwen; Peng, Yuyi

doi:10.1016/j.conbuildmat.2021.125620

Cited by 21 publications

(5 citation statements)

References 42 publications

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“…GGs have received considerable attention owing to their performance and environmental advantages [3,4]. Compared to ordinary Portland cement, GGs are more suitable for underground engineering construction because of their higher strength, impermeability, corrosion resistance, and volume stability [5][6][7][8][9]. The use of GGs has also alleviated environmental pollution caused by the accumulation of bulk solid waste.…”

Section: Introductionmentioning

confidence: 99%

Workability and environmental evaluation of using sunflower stalk ash (SSA) as an alkali activator with blast furnace slag (BFS) and black rice hull ash (BRHA) to prepare geopolymer grouts

Zhu,

Li,

Liu

et al. 2024

Preprint

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To solve the problem of environmental pollution from stockpiling of solid waste and to achieve safe and efficient underground engineering, an environment-friendly waste-based ternary geopolymer grout was developed using BFS, SSA, and BRHA. KOH-activated grouts were used as the controls. The applicability of grouts with different SSA additions was also investigated. The results showed that the 28-day compressive strength of SSA-activated grout reached 24.31 MPa, which exceeded that of the control group by 163.7%. Potassium and calcium salts, such as fairchildite and magnesium potassium silicate, in SSA promoted the formation of C(K)-A-S-H and C-S-H gels. The carbon emissions calculated from global warming potential in the life cycle assessment of the SSA system were 83.5% lower than those of KOH. The leaching results showed that the concentration of all heavy metals dropped below 0.02 mg/L after 28 days of solidification. The immobilization efficiencies of Cr, Pb, and Zn exceeded 98.65%, indicating the considerable immobilization ability of the SSA-activated grout and that it can be used safely in further applications. These findings support the treatment of solid waste resources and preparation of high-performance grouts for underground engineering.

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Section: Introductionmentioning

confidence: 99%

Workability and environmental evaluation of using sunflower stalk ash (SSA) as an alkali activator with blast furnace slag (BFS) and black rice hull ash (BRHA) to prepare geopolymer grouts

Zhu,

Li,

Liu

et al. 2024

Preprint

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“…The investigation into tunnel waste slag and sulphide minerals has increasingly become a focal point of research in tunnel construction. Utilizing backfilled waste slag as a filling material represents a prevalent method for the management of tunnel waste slag (Chen et al, 2020; Song et al, 2020; Song et al, 2022). However, the sulphide mineral components within the waste slag are prone to oxidation (Posfai et al, 1998), creating an acidic environment that facilitates the leaching of toxic substances from the mineral matrix, culminating in soil and groundwater contamination (Zhu et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

Synergistic mechanism of physical chemistry and acid bacteria: Product evolution of sulphides during tunnel mining

He,

Ren,

et al. 2024

Geological Journal

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Tunnel waste constitutes a prevalent by‐product of highway construction in high‐altitude mountainous and hilly regions. Sulphide minerals exhibit a unique distribution pattern within the alpine hills. Consequently, tunnel excavation can disrupt the stability of these sulphide minerals, rendering the tunnel waste susceptible to generating secondary environmental hazards during stockpiling. This research delves into the migration and transformation dynamics of potential environmental pollutants in tunnel waste through geoenvironmental simulation techniques. Controlled variables were employed to simulate various conditions, including surface illumination, internal anaerobiosis, water content and aerobic environments. The study's findings indicate that the presence of pyrite in the waste stream primarily drives the secondary contamination of the tunnel waste. Pyrite within the slag tends to react and form sulphuric acid in the stockpile environment, thus creating an acidic milieu that exacerbates the release of existing contaminants. The emergence of an anaerobic environment and a photocatalytic system composed of Fe/Ti substances in the waste stream serves to further accelerate pollutant release. This study thoroughly investigates the primary causes of environmental pollution during the stockpiling of tunnel slag and assesses the potential environmental impact scenarios. The outcomes of this research offer substantial theoretical and empirical support for the management of slag generated during the tunnel construction process.

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“…Component B is usually made up of Sodium silicate solution [8]. The two-component grout has an initial setting time and high initial strength and is generally used in water-rich layers [9]. Examples of projects using two-component grout for injecting behind the segment could be mentioned as Line C in Rome (Italy), Arroyo Maldonado hydraulic tunnel in Buenos Aires (Argentina), LAT tunnels in Singapore, Sparvo Tunnel (Italy), Belchen Tunnel in Switzerland, Nanjing Yangtze River Crossing Tunnel (China).…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Feasibility of Increasing the Tail-grouting Zone during Mechanized Tunneling in Sandy Soils

Barri,

Chakeri,

Haghkish

et al. 2023

Period. Polytech. Civil Eng.

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Nowadays, excavation in urban environments can have many risks; one of these hazards is improper tail-grouting of Earth Pressure Balance Machine (EPBM) and the consequent ground surface settlement. Failure to fill the tail space with suitable grout significantly affects the surface displacements. Injecting more grout to penetrate deeper around the tunnel will play a more effective role in reducing displacements and permeability of the soil. Therefore, experimentally investigation of the feasibility of increasing the tail-grouting zone during excavation around the tunnel space and the effect of this penetration on the amount of ground surface displacements is the main purpose of this paper. Thus, experimental tests were performed with different grout injection pressure and the effect of each of the pressure on the penetration depth of grout into the soil new laboratory model were examined. Then to study the effect of the grout penetration depth on surface settlement to determination of the adequate amount of grout injection pressure a numerical modeling of Tabriz metro line 2 by FLAC3D software were completed. For this purpose, the results of the laboratory tests (the penetration depth of grout) were used in numerical modeling. The results indicated that the amount of penetration in the implemented granulation has increased due to the increase in pressure, so doubling the pressure causes a 30% increase in grout penetration in the surrounding soil. The results of numerical studies showed that increasing the range of injection in the modeling causes a significant reduction (80 percent) in the ground surface settlement.

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Preparation and engineering properties of alkali-activated filling grouts for shield tunnel

Cited by 21 publications

References 42 publications

Workability and environmental evaluation of using sunflower stalk ash (SSA) as an alkali activator with blast furnace slag (BFS) and black rice hull ash (BRHA) to prepare geopolymer grouts

Workability and environmental evaluation of using sunflower stalk ash (SSA) as an alkali activator with blast furnace slag (BFS) and black rice hull ash (BRHA) to prepare geopolymer grouts

Synergistic mechanism of physical chemistry and acid bacteria: Product evolution of sulphides during tunnel mining

Investigation of the Feasibility of Increasing the Tail-grouting Zone during Mechanized Tunneling in Sandy Soils

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