Spatial distribution model of the filling and diffusion pressure of synchronous grouting in a quasi-rectangular shield and its experimental verification

Liu, Jun; Li, Peinan; Shi, Lai De; Fan, Jie; Kou, Xiaoyong; Huang, Dezhong

doi:10.1016/j.undsp.2021.02.002

Cited by 21 publications

(7 citation statements)

References 3 publications

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“…Initially, the grout fills the shield tail void circumferentially driven by injection pressure and gravity (Figure 1b). The completion of circumferential grout distribution along the segment generally takes tens to hundreds of seconds [31]. After the completion of circumferential grout filling, the grout fills the shield tail void longitudinally parallel to the movement direction of the shield machine.…”

Section: Mathematical Model 21 Assumptionsmentioning

confidence: 99%

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Pressure Model Study on Synchronous Grouting in Shield Tunnels Considering the Temporal Variation in Grout Viscosity

Ma,

Sun,

Jiang

et al. 2023

Applied Sciences

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The grout pressure in the shield tunnel tail void during synchronous grouting is the key to controlling ground settlement and restraining the segment. However, the circumferential, longitudinal, and radial distribution of grout pressure considering the temporal variation in grout viscosity has not been well explored yet. In this study, a theoretical model of grout pressure distribution and dissipation considering the temporal variation in Bingham grout viscosity was established. The simulation results of the pressure model were verified by field-measured data. The results showed that the radial and longitudinal distributions of grout pressure considering the temporal variation in grout viscosity were closer to the field-measured data. The impacts of the main parameters on the pressure distribution and dissipation were analyzed. Compared with the effect of the shield tail void thickness, tunnel radius and yield shear stress have greater effects on grout pressure during the circumferential filling phase. During the longitudinal and radial diffusion phases, the increase in soil porosity and permeability coefficient was conducive to grout diffusion. The increase in the grout viscosity reduces the pressure loss during the grout flow process. The results of this research can provide a theoretical basis for the grout design process in shield tunnels.

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Section: Mathematical Model 21 Assumptionsmentioning

confidence: 99%

“…Similar results were found in . The higher the yield shear stress of the grout, the stronger the hindrance to the flow process [31]. A higher yield shear stress causes a greater loss of grout pressure.…”

Section: Yield Shear Stress τmentioning

confidence: 99%

Pressure Model Study on Synchronous Grouting in Shield Tunnels Considering the Temporal Variation in Grout Viscosity

Ma,

Sun,

Jiang

et al. 2023

Applied Sciences

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“…The relationship between tunnel uplift and increase in the grouting strength was studied, and corresponding technical construction measures were proposed to reduce the uplift of the shield tunnel. Liu et al divided grout flow into two independent processes—circumferential filling and longitudinal diffusion—and established a theoretical model of the spatial distribution of the grouting pressure according to the principles of fluid mechanics ( 17 ). Then, the pressure distributions along two directions were calculated via an example, and the results were compared with measured data to verify the effectiveness of the model.…”

Section: Literature Reviewmentioning

confidence: 99%

Optimization of the Grout Mix Ratio and Simulation Test of Shield Tail Grouting Similarities in a Water-Rich Fine Sand Layer

Song,

Li,

Wang

et al. 2023

Transportation Research Record: Journal of the Transportation R

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When shield tunneling is performed in water-rich silt and fine sand strata, the grout becomes runny when diluted by groundwater. After dilution, the filling effect of the grout is not significant, and the level of surface settlement is very high. In this study, based on bidding section 04 of Tianjin Metro Line 11, traditional grouting materials were selected to conduct response surface method (RSM) tests. The purposes of the RSM analysis were to analyze the interactions between materials and their influences on grout performance and to optimize the grout mix ratio. Various admixtures were compared to assess the effects of different admixtures and compositions on the dispersion resistance and flow performance of the grout. Finally, a shield synchronous grouting test system was developed, and a similar indoor grouting simulation test was performed to analyze the influences of the different admixtures on the filling effects and to determine a reasonable grout mix ratio. The following three results were obtained. (1) The RSM was suitable for grout performance prediction and grout mix ratio optimization, and hydroxyethyl cellulose could improve the grout performance and increase the bond performance between the cementing material and aggregate. (2) Admixture incorporation enhancement could improve the grout utilization rate and increase the diffusion distance at the top of the tunnel, which would be conducive to filling the gap at the tail end of the shield. (3) The optimal preparation scheme of grout in water-rich fine sand formations included a water–binder ratio of 0.72, cement–sand ratio of 0.80, fly ash content of 5%, bentonite content of 14.94%, and admixture content of 0.8%–0.9%

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“…The cumulative float of segments in some sections had exceeded the warning value, which will cause uneven stress on the segment, resulting in stress concentration and segment damage. Many factors could affect tunnel floating, and these factors are often interrelated mutually such as geological conditions [6], synchronous grouting [12][13][14], and shield attitude control [15]. Based on the field monitoring data from the underwater tunnel mentioned above, two factors were discussed in this paper.…”

Section: Analysis Of Floating Mechanism Of Tunnel Segmentsmentioning

confidence: 99%

Study on the Floating of Large Diameter Underwater Shield Tunnel Caused by Synchronous Grouting

Huang²,

Gao³

et al. 2022

Geofluids

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Synchronous grouting is the key factor causing segment floating during the construction of shield tunnel, especially the grout ratio and the control of the grouting pressure. In this paper, the ratio of grout material was optimized through multiple groups of physical and mechanical tests. The results showed that 0.3% content of water reducing agent in grout could improve the ability of water resistance significantly. 2.9% content of bentonite could reduce bleeding rate of grout and grout setting time and improve the fluidity in the meantime. Then, the distribution law of grout along the segment ring in the filling stage was studied based on a typical underwater tunnel in China. The results showed that the theoretical calculation of grouting pressure was between 0.15 MPa and 0.18 MPa, which were in good agreement with the measured data. The grouting pressure distribution is affected by four parts including the lateral earth pressure, foundation reaction, grout shear stress, and gravity.

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Spatial distribution model of the filling and diffusion pressure of synchronous grouting in a quasi-rectangular shield and its experimental verification

Cited by 21 publications

References 3 publications

Pressure Model Study on Synchronous Grouting in Shield Tunnels Considering the Temporal Variation in Grout Viscosity

Pressure Model Study on Synchronous Grouting in Shield Tunnels Considering the Temporal Variation in Grout Viscosity

Optimization of the Grout Mix Ratio and Simulation Test of Shield Tail Grouting Similarities in a Water-Rich Fine Sand Layer

Study on the Floating of Large Diameter Underwater Shield Tunnel Caused by Synchronous Grouting

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