A new pressure gradient model of slurry shield pipeline system coupling with rheological properties and wall slip behaviour under sandy stratum

Guo, Yidong; Li, Xinggao; Jin, Dalong; Yang, Yi; Fang, Yingran; Zhang, Yazhou; Ye, Yangeng

doi:10.1016/j.tust.2023.105024

Cited by 7 publications

(2 citation statements)

References 42 publications

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“…Under low shear rate conditions, the sludge was in a laminar flow state, and the flocculent network structure formed between particles due to flocculation was sufficient to resist a certain amount of external force. Therefore, it was necessary to overcome the initial yield stress before flow occurs, and the viscosity of the fluid was high [21]. With the continuous increase in shear rate, the floc network structure had been damaged, so the sludge suspension exhibited almost homogeneous flow characteristics, and its viscosity remained basically unchanged [22].…”

Section: Analysis Of Typical Rheological Properties Of Sludgementioning

confidence: 99%

Investigating the Steady-State Rheological Properties of Activated Sewage Sludge for Effective Post-Treatment

Chen

et al. 2023

Sustainability

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Pipeline transportation has become an effective way to transport sludge from wastewater treatment plants due to its high transportation efficiency, low operating cost, and low environmental pollution. Before designing and optimizing the sludge-conveying pipeline, it is first necessary to analyze the rheological properties of the sludge. In this paper, activated sludge with varying volume concentrations (Cw) of 2.38%, 3.94%, and 5.39% was used as the research object. Under three temperature (T) conditions of 293 K, 298 K, and 303 K, the sludge concentration and temperature were investigated, and based on the results, a rheological model of activated sludge was established. The experimental results indicated that the upward and downward paths of the shear stress change curve were generally similar but did not overlap, and a hysteresis loop was formed between the two due to the characteristics of sludge shear thinning. The limiting viscosity of sludge with different concentrations increased with the increase in sludge concentration. This phenomenon was caused by the differences in the internal flocculent network structure of sludge with different concentrations and the different fluid flow effects. At different shear rates, the shear stress and sludge viscosity in the experiment decreased with the increase in temperature. The stability of the test sludge was weakened with the increase in temperature. Additionally, the viscosity of sludge decreased with the increase in shear rate and then stabilized, exhibiting shear thinning characteristics. The above rheological properties were described using the Bingham and Herschel–Bulkley models.

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Section: Analysis Of Typical Rheological Properties Of Sludgementioning

confidence: 99%

Investigating the Steady-State Rheological Properties of Activated Sewage Sludge for Effective Post-Treatment

Chen

et al. 2023

Sustainability

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“…Reasonable determination of the water flow and water pressure in the screw conveyor is of great significance in solving the problem of spewing. Shield model test and numerical simulation are effective methods to analyze the mechanism of spewing, some scholars have studied the transportation of soil in shield structure through model tests [15][16][17][18] and CFD [10,19,20], and the results show that the water pressure distribution within the screw conveyor under steady state seepage is approximated as one-dimensional seepage.…”

Section: Introductionmentioning

confidence: 99%

Analytical study of EPB shield spewing discrimination in auxiliary air pressure mode

Zheng,

Yu,

et al. 2023

Preprint

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Considering the effect of auxiliary air pressure on the shield seepage field, the spewing problem is analyzed by using an analytical method. Soil conditioning is currently the main method that can be used to prevent and control the occurrence of shield spewing, but there is a lack of research on how low the soil permeability coefficient should be conditioned. To further study the mechanism of the occurrence of spewing, this paper uses the variable separation method and the superposition principle to derive an analytical solution of the two-dimensional seepage field of the shield under the auxiliary air pressure mode, and calculates the critical permeability coefficient of spewing based on a previous study. The accuracy of the analytical solution is verified by comparison with numerical simulations. Parametric analyses show that when the auxiliary air pressure fluctuates at the lower design limit, it slightly helps to avoid spewing, but as the auxiliary air pressure becomes greater than the water pressure at the bottom of the cutter face, the risk of spewing will be greater than that of the closed mode. After the water pressure at the bottom of the cutter face is greater than 28m, the critical permeability coefficient of a typical size shield will be less than 10-4cm/s, and the empirical way of controlling the permeability coefficient to 10-4~10-3cm/s has a risk of spewing. By comparison with the spewing example, the prediction of the critical permeability coefficient of spewing by the analytical solution is proven to be effective.

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Modeling of reinforced-concrete cutting with shield rippers using FEM-DEM-coupling method

Jin,

Guo,

et al. 2024

International Journal of Mechanical Sciences

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A new pressure gradient model of slurry shield pipeline system coupling with rheological properties and wall slip behaviour under sandy stratum

Cited by 7 publications

References 42 publications

Investigating the Steady-State Rheological Properties of Activated Sewage Sludge for Effective Post-Treatment

Investigating the Steady-State Rheological Properties of Activated Sewage Sludge for Effective Post-Treatment

Analytical study of EPB shield spewing discrimination in auxiliary air pressure mode

Modeling of reinforced-concrete cutting with shield rippers using FEM-DEM-coupling method

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