Classification of jointed rock with emphasis on grouting

Hässler, Lars; Håkansson, Ulf; Stille, Håkan

doi:10.1016/0886-7798(92)90075-s

Cited by 11 publications

(6 citation statements)

References 3 publications

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“…The y-coordinate is the difference between 1 and κ, which is considered as 0.3 according to this study. Finally, the time and spatial distribution equation of κ is derived as shown in Equation (6).…”

Section: Results and Analysismentioning

confidence: 99%

“…The grouting effect depends on both the property of the grouted medium and the rheology of the grout. For permeation grouting in a porous medium, such as sand layers, the most important parameter is the permeability, which is, to a large extent, dependent on the viscosity of the grout, and the available opening in the porous medium [5,6]. The permeability influences the design parameters during the grouting process, such as grouting pressure and grouting holes distance.…”

Section: Introductionmentioning

confidence: 99%

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Modeling of Grouting Penetration in Porous Medium with Influence of Grain Distribution and Grout–Water Interaction

et al. 2021

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In this study, a numerical model of grouting penetration in a porous medium is established. The fluid flow in the interstices of the porous medium is directly modeled by Navier–Stokes equations. The grouting process is considered as a two-phase flow problem, and the level set method is used to characterize the interaction between grout and groundwater. The proposed model has considered the nuances for each grain during grouting penetration, instead of representing the fluid flow as a continuum process. In the simulation, three kinds of porosity (0.3; 0.4; 0.5) and two kinds of grain size distribution (0.5~1 mm; 1~2 mm) are used. Results show that: the pressure drop along penetration distance is approximately in a linear trend. The variation of filling degree along grouting distance approximately obeys a quadratic polynomial function. The injection pressure is influenced by the porosity and grain size of the porous medium, especially by the former. A theoretical analysis is carried out to propose an analytical solution of the grouting penetration. The analytical solution gives a good estimation when the grain amounts in the porous medium are small, and the difference becomes larger as the grain amounts increase.

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Section: Results and Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modeling of Grouting Penetration in Porous Medium with Influence of Grain Distribution and Grout–Water Interaction

et al. 2021

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“…Some theoretical models have been developed for predicting the take of cement grout in jointed rocks and enable one to estimate the grout penetration length in a single joint. Hässler et al (1992) presented a theoretical based relationship for determination of maximum grout penetration length in a joint, which is controlled by factors such as pressure, grout properties and the joint aperture. Hässler et al (1992), Gustafson and Stille (1996) and Funehag and Fransson (2006) assessed the penetration of grout in well characterized fractures and concluded that the hydraulic aperture is a reasonable predictor for penetration length.…”

Section: Introductionmentioning

confidence: 99%

“…Hässler et al (1992) presented a theoretical based relationship for determination of maximum grout penetration length in a joint, which is controlled by factors such as pressure, grout properties and the joint aperture. Hässler et al (1992), Gustafson and Stille (1996) and Funehag and Fransson (2006) assessed the penetration of grout in well characterized fractures and concluded that the hydraulic aperture is a reasonable predictor for penetration length. Recently the critical aperture for field penetrability was investigated and verified by data from some grouting projects (Stille et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Estimation of the grout take using empirical relationships (case study: Bakhtiari dam site)

Sohrabi-Bidar

Rastegarnia

Zolfaghari³

2015

Bull Eng Geol Environ

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Seepage in the foundation and abutments of a dam can lead to wasting of the stored water in the reservoir, erosion of the foundation materials and increasing the uplift pressure. It can endanger the long term stability of the dam. Cement grouting is one of the seepage control methods which is generally implemented according to the Lugeon test results. In this study, the grout volume has been examined against Q-value, Lugeon number, SPI (Secondary permeability index) value and joint apertures in the Bakhtiari dam site. In Bakhtiari dam site, the left and the right abutment trial grouting boreholes were drilled up to the final depth of 60 and 100 m, respectively. Limestone of the Sarvak Formation is the dominant rock type in the site. The Q-system parameters have been evaluated by eyeexamination of rock cores, the Lugeon numbers and SPI values have been deduced from the water pressure tests and the joint apertures have been calculated based on the permeability of rock mass and the joints spacing. The Q-value, the Lugeon number, the SPI value and the joint aperture have been compared with measured cement take and grout take in the trial grouting boreholes. A general correlation exists, especially when the mentioned parameters have been compared with normalized grout take. Against these general agreements the coefficients of determination for the fitted relations are low or moderate, and it seems that more research has been needed to assessing a reliable predictive relation for the grout and cement takes.

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“…This model was used to establish an equation based on volume fractions and porosity of grout to calculate distribution of grouting pressure and define the effective grout diffusion radius; Liu et al, (2021) established an analytical model of backfill grout-consolidation to study grout-cake thicknesses and pressure decay behind tunnel segmental linings, and suggested that the grout pressure cannot be ignored when assessing the safety of a tunnel lining. In terms of experimental tests, Hässler (1991) set two pipe diameters (3 mm and 4 mm) based on a circular pipe simulation platform to explore the diffusion distance of cement grout under constant grouting pressure, and reveal the diffusion model based on Bingham fluid; Majidi et al, (2010) conducted numerical and experimental research on the diffusion radius of yield plastic grout based on smooth plate fracture, and discussed the head loss during grout diffusion. Zhang et al, (2018) proposed a theoretical formula for the Bingham flow of cement grout under constant pressure, but the change in velocity therein is simplified, so it is only suitable for the later stage of diffusion.…”

mentioning

confidence: 99%

Investigation of grouting diffusion in a single rock fracture considering the influences of obstructions

et al. 2022

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Grouting reinforcement was used to improve rock strength and avoid seepage in rock engineering. A self-developed visualised test platform was developed and the influences of different fracture openness on grouting diffusion modes were revealed; the Bingham rheological model was imported to simulate the grouting diffusion process in a single plate fracture, the spatio-temporal distribution of the velocity field under different obstructions was determined using the finite element method. The results indicate that: 1) The grout diffuses faster with the increase of fracture openness, while a stagnation effect of the grouting diffusion velocity behind the obstruction occurs. 2) Due to obstructions, the grouting diffusion process can be divided into four stages: circular diffusion, flat diffusion, vortex diffusion, and butterfly diffusion. 3) The grouting diffusion area is divided into a fully-reinforced zone and a semi-reinforced zone, and the area of the latter increases with the fracture openness, while being little affected by the size of any obstruction. 4) Furthermore, some new grouting diffusion laws were revealed considering the asymmetrical arrangement of obstructions. The results presented in this work will be helpful for describing and predicting the grouting process in fracture networks.

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Classification of jointed rock with emphasis on grouting

Cited by 11 publications

References 3 publications

Modeling of Grouting Penetration in Porous Medium with Influence of Grain Distribution and Grout–Water Interaction

Modeling of Grouting Penetration in Porous Medium with Influence of Grain Distribution and Grout–Water Interaction

Estimation of the grout take using empirical relationships (case study: Bakhtiari dam site)

Investigation of grouting diffusion in a single rock fracture considering the influences of obstructions

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