Analytically-based simplified formulas for circular tunnels with two liners in viscoelastic rock under anisotropic initial stresses

Song, Fei; Wang, Huaning; Jiang, Mingjing

doi:10.1016/j.conbuildmat.2018.04.079

Cited by 62 publications

(39 citation statements)

References 36 publications

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“…In the fitting procedure, the indicator R2, i.e., the adjusted coefficient of determination [33], was introduced to evaluate the fitting accuracy. R2 is a statistical measure that shows the proportion of variation explained by the estimated regression line [34]. The closer R2 is to 1.0, the better the fitted formula explains the relationship of experimental data.…”

Section: Analysis Of Consolidation Compression Characteristicsmentioning

confidence: 99%

Compression Characteristics and Microscopic Mechanism of Coastal Soil Modified with Cement and Fly Ash

Zhu

Wang

et al. 2019

Materials

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It is of great significance to study the consolidation characteristics of modified coastal cement-soil. A one-dimensional consolidation test and microscopic test were carried out. In the tests, the cement content was 20%, fly ash content was 0%, 5%, 10%, 20%, and 30%, and the water content was 80%. The consolidation test results showed that: (1) Compared with coastal cement soil, the deformation of coastal cement soil modified with a 20% fly ash content was reduced from 4.31 to 2.70 mm, and the vertical compression deformation was reduced by 1.61 mm. (2) During consolidation and compression, the e–p curve (pore ratio-pressure curve) of fly ash-modified coastal cement soil was slower than that of coastal cement soil and the rate of change of pore ratio. (3) The compression coefficient of fly ash-modified coastal cement soil was reduced from 0.780 to 0.598 MPa-1 compared with that of coastal cement soil. The microscopic test results indicate that after adding the proper amount of fly ash, a skeleton was formed between the microscopic particles of the sample, which improved its resistance to compression and deformation. The results of this study indicate that it is feasible to modify coastal cement soil with an appropriate amount of fly ash to improve its compression resistance.

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Section: Analysis Of Consolidation Compression Characteristicsmentioning

confidence: 99%

Compression Characteristics and Microscopic Mechanism of Coastal Soil Modified with Cement and Fly Ash

Zhu

Wang

et al. 2019

Materials

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“…Figures 13 and 14 show the resulting response surfaces for these functions. We used the adjusted coefficient of determination (R 2 ) to evaluate the fitting accuracy [77,78]. The results were all excellent, with an adjusted R 2 value >0.93.…”

Section: Parameterized Functionsmentioning

confidence: 99%

Effect of Density and Total Weight on Flow Depth, Velocity, and Stresses in Loess Debris Flows

Shu

et al. 2018

Water

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Debris flows that involve loess material produce important damage around the world. However, the kinematics of such processes are poorly understood. To better understand these kinematics, we used a flume to measure the kinematics of debris flows with different mixture densities and weights. We used sensors to measure pore fluid pressure and total normal stress. We measured flow patterns, velocities, and depths using a high-speed camera and laser range finder to identify the temporal evolution of the flow behavior and the corresponding peaks. We constructed fitting functions for the relationships between the maximum values of the experimental parameters. The hydrographs of the debris flows could be divided into four phases: increase to a first minor peak, a subsequent smooth increase to a second peak, fluctuation until a third major peak, and a final continuous decrease. The flow depth, velocity, total normal stress, and pore fluid pressure were strongly related to the mixture density and total mixture weight. We defined the corresponding relationships between the flow parameters and mixture kinematics. Linear and exponential relationships described the maximum flow depth and the mixture weight and density, respectively. The flow velocity was linearly related to the weight and density. The pore fluid pressure and total normal stress were linearly related to the weight, but logarithmically related to the density. The regression goodness of fit for all functions was >0.93. Therefore, these functions are accurate and could be used to predict the consequences of loess debris flows. Our results provide an improved understanding of the effects of mixture density and weight on the kinematics of debris flows in loess areas, and can help landscape managers prevent and design improved engineering solutions.

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“…The size of deformation is related to rock mass properties, in-situ stress and support condition [1][2][3][4]. It is important to analyze the distribution of stress field and displacement field of surrounding rock by theoretical calculation [5][6][7]. Based on the ideal elastic-plastic model, Fenner and Kastner analyzed the elastic and plastic zones of tunnels and derived Fenner formula and Kastner formula [8].…”

Section: Introductionmentioning

confidence: 99%

Optimal Support Solution of Soft Rock Roadway Based on Drucker-Prager Yield Criteria

Guo

Pan

2021

Preprint

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Through theoretical calculation, the stress and deformation of surrounding rock can be analyzed, which can provide guidance for support design and optimization of soft rock roadway. In this paper, theoretical solutions for both the optimal support pressure and the allowable maximum displacement of surrounding rock are derived based on the Drucker-Prager (DP) yield criteria and the steady creep criterion expressed by the third invariant of deviator stress. The DP criteria with different parameters are compared and analyzed by an engineering example. Then, based on the calculation results, the effects of long-term strength, cohesion and internal friction angle of soft rock on the maximum plastic zone radius and allowable maximum displacement of roadway are discussed. The results show that the optimal support solution of soft rock roadway based on DP criteria can not only reflect the intermediate principal stress reasonably, but also can compare and discuss the influence of different DP criteria on the calculation results. The higher the long-term strength of the roadway surrounding rock is, the smaller the optimal support force is and the larger the allowable maximum displacement is. When the calculated long-term strength of soft rock can ensure that the deformation of the roadway does not exceed the allowable maximum displacement, the roadway can maintain long-term stability without support. With the increase of the cohesion or internal friction angle of soft rock, the radius of plastic zone decreases gradually, and the allowable maximum displacement is reduced by degrees. Through grouting and other means to improve the strength of surrounding rock can effectively reduce the roadway deformation and save support costs.

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Analytically-based simplified formulas for circular tunnels with two liners in viscoelastic rock under anisotropic initial stresses

Cited by 62 publications

References 36 publications

Compression Characteristics and Microscopic Mechanism of Coastal Soil Modified with Cement and Fly Ash

Compression Characteristics and Microscopic Mechanism of Coastal Soil Modified with Cement and Fly Ash

Effect of Density and Total Weight on Flow Depth, Velocity, and Stresses in Loess Debris Flows

Optimal Support Solution of Soft Rock Roadway Based on Drucker-Prager Yield Criteria

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