An analytical solution for the radial flow of variable density grout in rock fractures

Li, Xiaolong; Wang, Lianbang; Hao, Meimei; Zhong, Yanhui; Zhang, Bei

doi:10.1016/j.conbuildmat.2019.02.089

Cited by 35 publications

(11 citation statements)

References 19 publications

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“… 4 − 7 Other scholars considered the theoretical basis of fluid mechanics and the distribution state of cracks and established analytical formulas such as grouting diffusion range and diffusion speed. 8 − 12 To evaluate the rock strength after grouting, Zhang et al 13 established a preliminary theoretical model and an empirical formula for rock strength after grouting, which enabled prediction of the rock strength after grouting. In summary, scholars worldwide mainly use theoretical analysis, experimental analysis, and numerical simulation to evaluate the slurry diffusion and the effect of rock mass reinforcement, which greatly enriches and develops grouting theory.…”

Section: Introductionmentioning

confidence: 99%

Analytical Solution of the Grouting Reinforcement Response of a Circular Cavern in Deeply Buried Fractured Surrounding Rock under a Nonuniform Stress Field

Liu

Lyu

et al. 2022

ACS Omega

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Grouting is widely utilized to reinforce fractured surrounding rock. However, presently, the secondary stress distribution of fractured surrounding rock after grouting is not distinct, which hinders the accurate evaluation of the grouting effect. Therefore, a complex variable function solution is provided for the evolution of the stress field and the displacement field around the reinforced fractured surrounding rock subjected to a nonuniform load. By comparing the evolution of the stress and radial displacement fields around the cavern, the reinforcement effect on the fractured surrounding rock is quantitatively confirmed. The results show that grouting has an obvious modification effect on fractured surrounding rock: its radial stress and circumferential stress fields are affected to different degrees, and the circumferential stress is more obvious. Grouting makes the circumferential stress peak transfer from the wall of the cavern to the roof and floor of the cavern, which is beneficial to the stability of the cavern. The radial displacement around the cavern also decreases. The displacement of the wall decreases by approximately 24.0%, and the radial displacement of the roof and floor decreases by approximately 61.8%.

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Section: Introductionmentioning

confidence: 99%

Analytical Solution of the Grouting Reinforcement Response of a Circular Cavern in Deeply Buried Fractured Surrounding Rock under a Nonuniform Stress Field

Liu

Lyu

et al. 2022

ACS Omega

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“…the pressure gradient across the aperture is negligible by adopting the lubrication approximation). Then, the Reynolds equation can be written as (Li et al 2019), where μ is the kinetic viscosity, and for water at 20 °C, μ = 1.01 × 10 −3 Pa•s. P is the hydraulic pressure and v r represents the radial velocity.…”

Section: Governing Equationsmentioning

confidence: 99%

Size effect on the hydraulic behavior of fluid flow through rough-walled fractures: a case of radial flow

Zhong

Ding

2021

Hydrogeol J

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This study provides a numerical approach to investigate radial flow through a single rough-walled fracture. To facilitate the size-dependency investigation, rough-walled fractures as large as 18 m were generated by using tiny cubes to mimic fracture asperities. Subsequently, a two-dimensional Reynolds equation was solved to simulate radial flow through the rough fractures with various fracture apertures and roughness values. The impact of normal stress on the hydraulic properties was incorporated by using a hyperbolic function. The results show clear evidence for size dependence of hydraulic conductivity. In particular, the hydraulic conductivity globally increases with increasing fracture radius until a given size, which if exceeded causes the hydraulic conductivity to approach an asymptotic value. Therefore, the given size can be considered as the representative size, which is determined to be a radius ranging from 12 to 17 m, attributing to the variations in fracture aperture, roughness and normal stress. It was also found that the representative size decreases with an increment in the fracture aperture; this tends to increase as the fracture roughness or the normal stress increases, since those factors will more or less alter the fracture topology and contact areas, which play a key role in controlling the tortuosity and connectivity of radial flow through a rough fracture. This article gives some insight into size dependence of radial flow through a single rough fracture and places an emphasis on the representative size, which, when it does exist, must be identified before correlating the laboratory-scale investigations to in-situ applications.

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“…Around the tail of the shield, owing to the filling effect of grout behind the segment, the gap might disappear. During tunneling, in addition to synchronous grouting of the gap at the tail of the shield, secondary grouting was also conducted through the grouting holes on the segments, and thus it can be considered that there was no groundwater seepage around the segment rings after the shield tail [27,28]. When establishing the water seepage model, it was assumed that the chamber soil was saturated, and the excavation surface and surrounding rock of the shield were considered as the groundwater seepage surfaces.…”

Section: Principle Of the Seepage Calculationmentioning

confidence: 99%

Phenomenon and Critical Conditions of Chamber Soil Sliming during EPB Shield Tunneling in Water‐Rich Weathered Diorite: Case Study of Jinan Metro, China

Wang

Qian

et al. 2020

Advances in Civil Engineering

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The sliming problem of chamber soil is caused by excessive groundwater seeping into the pressure chamber when an Earth pressure balance shield tunnels through a water-rich weathered rock stratum under semiopen under-pressure mode. As a solution to this problem, a calculation model was established based on field measurements of the discharged soil properties, the seepage water volume, and the seepage path in Jinan Metro, China. Chamber soil sliming is a phenomenon in which chamber soil is in a thin mud state, with no pressure balance in the pressure chamber of the EPB shield and an excessive water content of the chamber soil owing to the continuous seepage of groundwater into the chamber. The chamber pressure is relatively low, which is different from the phenomenon of spewing when the chamber pressure is relatively high. A large amount of water seepage from the stratum around the tunnel excavation surface and shield to the chamber is a significant factor leading to chamber soil sliming during the construction process. It was considered that when the moisture content of the chamber soil, w, is 2wL ≤ w ≤ 3wL, slight chamber soil sliming may occur, whereas when w ≥ 3wL, serious chamber soil sliming may occur. Moreover, some measures to prevent and control the occurrence of chamber soil sliming were discussed. Controlling the advancing time and the permeability coefficient of chamber soil during construction is the most effective measure to avoid the phenomenon of soil sliming.

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An analytical solution for the radial flow of variable density grout in rock fractures

Cited by 35 publications

References 19 publications

Analytical Solution of the Grouting Reinforcement Response of a Circular Cavern in Deeply Buried Fractured Surrounding Rock under a Nonuniform Stress Field

Analytical Solution of the Grouting Reinforcement Response of a Circular Cavern in Deeply Buried Fractured Surrounding Rock under a Nonuniform Stress Field

Size effect on the hydraulic behavior of fluid flow through rough-walled fractures: a case of radial flow

Phenomenon and Critical Conditions of Chamber Soil Sliming during EPB Shield Tunneling in Water‐Rich Weathered Diorite: Case Study of Jinan Metro, China

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