Study of the effect of micro-pore characteristics and saturation degree on the longitudinal wave velocity of sandstone

Wang, Junbao; Ren, Zhenzhong; Song, Zhanping; Huo, R.; Yang, Tengtian

doi:10.1007/s12517-019-4566-y

Cited by 17 publications

(12 citation statements)

References 35 publications

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“…Due to the particularity of loess, the deformation regularity in loess tunnels shows different characteristics from those in rock tunnels [12][13][14][15][16][17]. Deformation has four characteristics: scientific, timeliness, reliability, and convenience, and is widely used to evaluate tunnel stability and ensure construction safety [18][19][20][21][22][23][24][25]. e deformation of surrounding rock in loess is mainly affected by water content, cover depth, construction method, and construction procedure [26].…”

Section: Introductionmentioning

confidence: 99%

Statistical Analysis of Influence of Cover Depth on Loess Tunnel Deformation in NW China

Lai

et al. 2019

Advances in Civil Engineering

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Loess is a kind of special soil with structure and hydrocollapse behavior; due to the particularity of loess, the deformation regularity of the tunnel in loess shows different characteristics from those in rock. To ensure the safety of construction, crown settlement (CS) and horizontal convergence (HC) are widely used to assess the stability of the tunnel structural system. Based on statistical analysis, this study focused on analyzing the influence of cover depth on the deformation of surrounding rock of loess tunnels by ANOVA, and relationships between them were presented by regression analysis. The achieved results indicated that the influence of cover depth on deformation was not obvious in shallow tunnels, while the cover depth had a significant effect on deformation in deep tunnels. Based on the difference of influence of cover depth on deformation between shallow tunnels and deep tunnels, a method for determining the cover depth threshold (CDT) in the tunnel by statistical analysis was proposed. The horizontal and vertical deformations in shallow tunnels were discrete and obeyed the positive distribution, mainly concentrated within 200 mm. The deformation allowance in shallow tunnels was recommended to be 200 mm. In deep tunnels, as the cover depth increased, the deformation increased linearly, while the CS/HC decreased.

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Section: Introductionmentioning

confidence: 99%

Statistical Analysis of Influence of Cover Depth on Loess Tunnel Deformation in NW China

Lai

et al. 2019

Advances in Civil Engineering

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“…The surrounding rock and strengthened primary support were simulated by solid elements with a Mohr-Coulomb model as the constitutive model. [28][29][30][31] The primary support, temporary support, and secondary lining were simulated by plate elements with an elastic structure as the constitutive model. The sewage pipe was simulated by embedded beam elements with an elastic structure as the constitutive model.…”

Section: Geological Model and Boundary Conditionsmentioning

confidence: 99%

Study on adaptability of primary support arch cover method for large-span embedded tunnels in the upper-soft lower-hard stratum

Wang

Song

et al. 2019

Advances in Mechanical Engineering

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The Provincial Hospital Station of Guiyang Metro Line No. 2 in China is located on the upper-soft lower-hard stratum. In order to analyze the adaptability of primary support arch cover method for the project, the construction process of the main tunnel of the Provincial Hospital Station is simulated by virtue of numerical simulation. Meanwhile, the excavation process of the tunnel is simulated by the double-side drift method for comparison. The numerical simulation results show that the primary support arch cover method has advantages in settlement control, plastic zone distribution, and supporting structure safety. Only the primary supporting structure is relatively weak in the rock-soil interface and on the arch shoulders and vault, and liable to tension failure. However, the application of strengthened primary support can significantly improve this unfavorable situation. Therefore, it is suggested that the primary support arch cover method be adopted for the construction of the main tunnel of the Provincial Hospital Station. The numerical simulation results obtained by primary support arch cover method are consistent with the field data in terms of the change trend of surface settlement, and the final settlement value is also similar. On this basis, the influence of grade variation of underlying surrounding rock on surface settlement and surrounding rock plastic zone distribution caused by the two methods is further simulated, and the grade range of underlying surrounding rock suitable for primary support arch cover method is given in the article.

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“…Studies on rock pore structures and damage have adopted a variety of advanced testing techniques, such as mercury injection testing [14,15], scanning electron microscopy (SEM) [16][17][18], computerized tomography (CT) [19][20][21][22][23], and NMR [24][25][26][27]. Each has its own advantages and disadvantages.…”

Section: Introductionmentioning

confidence: 99%

NMR Experimental Study on Dynamic Process of Pore Structure and Damage Mechanism of Sandstones with Different Grain Sizes under Acid Erosion

Wang

et al. 2020

Shock and Vibration

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In many engineering projects, it is critical to consider the acid erosion of rock. This study investigates dynamic changes in pore structure and damage mechanisms in sandstones subjected to acid erosion. Specimens with three grain sizes were immersed in acid solution and tested by the nuclear magnetic resonance technique. Changes in solution pH, specimen mass and porosity, T2 spectrum distribution, and area were analyzed. Damage mechanisms are discussed, and relationships between porosity and acid erosion damage variables are established. The results show that acid erosion has significant effects on pore structure and erosion damage in sandstone. With increasing soaking time, new micropores formed in sandstone, while existing micropores and mesopores gradually expanded into macropores, causing the T2 spectrum distributions to change greatly. The porosity, acid erosion damage, and T2 spectral areas of sandstones with different grain sizes all increased gradually. Under acid erosion, sandstones became gradually weakened, but the effects varied greatly according to grain size. Pore structure changes and acid erosion damage were greatest in coarse-grained sandstone, followed by medium- and fine-grained sandstone.

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Study of the effect of micro-pore characteristics and saturation degree on the longitudinal wave velocity of sandstone

Cited by 17 publications

References 35 publications

Statistical Analysis of Influence of Cover Depth on Loess Tunnel Deformation in NW China

Statistical Analysis of Influence of Cover Depth on Loess Tunnel Deformation in NW China

Study on adaptability of primary support arch cover method for large-span embedded tunnels in the upper-soft lower-hard stratum

NMR Experimental Study on Dynamic Process of Pore Structure and Damage Mechanism of Sandstones with Different Grain Sizes under Acid Erosion

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