Investigation of hydraulic parameters of a weathered mylonite fault from field pumping tests: A case study

Liu, Xiaoxue; Xu, Ye‐Shuang; Cheng, Wen-Chieh; Horpibulsuk, Suksun

doi:10.1007/s10064-016-0910-6

Cited by 18 publications

(23 citation statements)

References 48 publications

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“…The meshed range is set to be 400 m ( x ) × 60 m ( y ) × 400 m ( z ). The dimension in a horizontal plane of xz is twice more than the maximum influence radius of pumping wells during a weathered mylonite, to ensure constant water‐level boundary condition . The geological strata presented Figure are divided into six strata and is represented by 15 layers, among which artificial fill occupies a layer; silty clay and sand coexists in the same layer; sandy clay takes up one layer; the highly, moderately, and slightly weathered rocks include three, two, and seven layers, respectively.…”

Section: Comparison Between Analytical Solutions and Numerical Resultsmentioning

confidence: 99%

“…As shown in Figure , the hydraulic conductivity of the foam conditioned mylonite k f reduces from 2.65 × 10 −6 to 8.85 × 10 −7 m/s when the shear stress of foam fluid τ s increases from 5 × 10 −4 to 1.5 × 10 −3 MPa. The hydraulic coefficient of original mylonite is about 6.48 × 10 −5 m/s . The hydraulic coefficient of the foam conditioned mylonite is one to two orders of magnitudes lower than the original mylonite due to the foam conditioning.…”

Section: Analytical Solutions Of a Groundwater Inflow Casementioning

confidence: 92%

“…7, Guangzhou city (China). Figure presents the longitudinal geotechnical profiles of investigated tunnel section . The mylonite fault is a dynamo‐metamorphic product of weathered siltstone and migmatite granite.…”

Section: Analytical Solutions Of a Groundwater Inflow Casementioning

confidence: 99%

“…The initial water level for the fissure confined aquifer is set to be 2 m below the ground, and the water level at tunnel cutting face is set as 14.5 m in the calculation . The influence radius induced by water inflow is identified as 200 m based on the data of pumping test . As shown in Figure , the relationship between α n ( t ) and β n can be obtained by submitting the above filed data into Equation .…”

Section: Analytical Solutions Of a Groundwater Inflow Casementioning

confidence: 99%

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Evaluation of foam conditioning effect on groundwater inflow at tunnel cutting face

Liu

Shen

Zhou

et al. 2018

Num Anal Meth Geomechanics

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Summary This paper presents an analytical evaluation on the influence of foam conditioning on groundwater inflow at shield tunnel cutting face by the force‐equilibrium principle. Three key variables are highlighted, namely, the maximum foam infiltration distance, the critical infiltration distance, and the hydraulic conductivity of foam‐conditioned soil or rock fissure. To capture the variation of water level induced by foam injection, a dynamic water‐level equation is considered in the force‐equilibrium principle. The proposed analytical equations are employed to analyze a water inflow case during shield tunneling in a weathered mylonite fault. The results indicate that the hydraulic conductivity of foam‐conditioned mylonite and the infiltration distance decrease with an increase of shear stress of foam fluid. A three‐dimensional finite element model is employed to validate the analytical solutions. The comparison between the observed and calculated results confirms that the proposed method can predict groundwater inflow in foam‐conditioned soils.

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Section: Comparison Between Analytical Solutions and Numerical Resultsmentioning

confidence: 99%

Section: Analytical Solutions Of a Groundwater Inflow Casementioning

confidence: 92%

Section: Analytical Solutions Of a Groundwater Inflow Casementioning

confidence: 99%

Section: Analytical Solutions Of a Groundwater Inflow Casementioning

confidence: 99%

See 2 more Smart Citations

Evaluation of foam conditioning effect on groundwater inflow at tunnel cutting face

Liu

Shen

Zhou

et al. 2018

Num Anal Meth Geomechanics

Self Cite

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show abstract

“…According to the exposure conditions, the karst can be divided into two categories: (1) exposed and semi-exposed karst; and (2) The strata in Guangzhou can be divided into nine categories, from top to bottom: (1) back fill layer; (2) silt layer; (3) alluvial-diluvial sand layer; (4) alluvial-diluvial clay layer; (5) residual soil layer; (6) completely weathered bedrock layer; (7) highly weathered bedrock layer; (8) moderately weathered bedrock layer; and (9) slightly weathered bedrock layer. Based upon past experience [68], during shield tunneling the excavation face may encounter mixed ground containing a soft layer (e.g., clay) at the top and a hard layer (e.g., granite) at the bottom, namely the so-called upper-soft lower-hard strata. It is anticipated that while shield tunneling within the upper-soft lower-hard strata, an excessive wearing of the cutter bits and an upward alignment deviation would result in a reduction in the advance rate and additional frictional resistance, respectively, thus affecting construction progress [69][70][71][72].…”

Section: Hydrogeology and Engineering Geology Of Guangzhoumentioning

confidence: 99%

Fractal Prediction of Grouting Volume for Treating Karst Caverns along a Shield Tunneling Alignment

et al. 2017

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Karst geology is common in China, and buried karst formations are widely distributed in Guangdong province. In the process of shield tunneling, the abundant water resources present in karst caverns could lead to the potential for high water ingress, and a subsequent in situ stress change-induced stratum collapse. The development and distribution of karst caverns should therefore be identified and investigated prior to shield tunnel construction. Grouting is an efficient measure to stabilize karst caverns. The total volume of karst caverns along the shield tunneling alignment, and its relationship with the required volume of grouts, should be evaluated in the preliminary design phase. Conventionally, the total volume of karst caverns is empirically estimated based on limited geological drilling hole data; however, accurate results are rarely obtained. This study investigates the hydrogeology and engineering geology of Guangzhou, the capital of Guangdong province, and determines the fractal characteristics of the karst caverns along the tunnel section of Guangzhou metro line no. 9. The karst grouting coefficients (V R ) were found to vary from 0.11 in the case of inadequate drilling holes to 1.1 in the case where adequate drilling holes are provided. A grouting design guideline was furthermore developed in this study for future projects in karst areas.

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Analytical approach for time‐dependent groundwater inflow into shield tunnel face in confined aquifer

Liu

Shen

Yin

2017

Num Anal Meth Geomechanics

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Summary Prediction of time‐dependent groundwater inflow into a shield tunnel is a significant task facing engineers. Published literature shows that there is no available method with which to predict time‐dependent groundwater inflow into a tunnel. This paper presents a prediction approach for time‐dependent groundwater inflow into a tunnel in both anisotropic and isotropic confined aquifers. The proposed solution can predict groundwater inrush from the tunnel cutting face. To obtain the time‐dependent groundwater flow quantity, the concept of a horizontal‐well pumping test based on the theory of a point source is adopted. Multiple factors, eg, drawdown, thickness of aquifer, conductivities, and specific storage, are taken into account. Both groundwater inflow to the cross section of a tunnel face in the y‐z plane and total tunnel inflow are obtained. Based on the proposed approach, the time‐dependent groundwater inflow to a tunnel can be classified as either a uniform or non‐uniform flow. The proposed approach is applied to analyse groundwater inflow of 2 field cases: (1) Metro line No. 7, Guangzhou City and (2) an underground tunnel in Huizhou, Guangdong Province. Results show that the proposed method can predict the measured values, and drawdown‐related curves are also derived. In addition, the calculated results also reveal that the effect of hydraulic conductivity kz on the total groundwater inflow differs from that of hydraulic conductivities kx and ky and the thickness of the aquifer.

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Investigation of hydraulic parameters of a weathered mylonite fault from field pumping tests: A case study

Cited by 18 publications

References 48 publications

Evaluation of foam conditioning effect on groundwater inflow at tunnel cutting face

Evaluation of foam conditioning effect on groundwater inflow at tunnel cutting face

Fractal Prediction of Grouting Volume for Treating Karst Caverns along a Shield Tunneling Alignment

Analytical approach for time‐dependent groundwater inflow into shield tunnel face in confined aquifer

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