Stability of two circular tunnels at different depths in cohesive-frictional soils subjected to surcharge loading

Xiao, Yao; Zhao, Minghua; Zhang, Rui; Zhao, Heng; Peng, Wenzhe

doi:10.1016/j.compgeo.2019.04.006

Cited by 28 publications

(11 citation statements)

References 31 publications

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“…In the last two decades, the FELA methods are routinely used to analyze a variety of geotechnical engineering stability problems, which combine the limit theorems of classical plasticity with finite elements to give the UB and the LB on the collapse load [38]. ese techniques do not require the load-settlement curve and assumptions about the collapse mode to determine the limit load, which have been widely used in stability analysis of strip footings [39][40][41], tunnels [42][43][44][45][46], slopes [14,[47][48][49], and anchors [50,51].…”

Section: Adaptive Finite Element Limit Analysismentioning

confidence: 99%

Seismic Bearing Capacity of Strip Footings on Cohesive Soil Slopes by Using Adaptive Finite Element Limit Analysis

Luo

Zhao

Xiao

et al. 2019

Advances in Civil Engineering

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By employing adaptive finite element limit analysis (AFELA), the seismic bearing capacity of strip footing on cohesive soil slopes are investigated. To consider the earthquake effects, the pseudostatic method is used. The upper and lower bounds for the seismic bearing capacity factor (Nce) are calculated, and the relative errors between them are found within 3% or better by adopting the adaptive mesh strategy. Based on the obtained results, design tables and charts are provided to facilitate engineers use, and the effects of footing position, undrained shear strength, slope angle, slope height, and pseudostatic acceleration coefficient are studied in detail. The collapse mechanisms are also discussed, including overall slope failure and foundation failure.

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Section: Adaptive Finite Element Limit Analysismentioning

confidence: 99%

Seismic Bearing Capacity of Strip Footings on Cohesive Soil Slopes by Using Adaptive Finite Element Limit Analysis

Luo

Zhao

Xiao

et al. 2019

Advances in Civil Engineering

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“…Figure 1 presents the main influential factors of a dual tunnels system. Following previous studies [6][7][8][9]12,15,16,[22][23][24][25][26]29], tunnel length is considered as infinite; therefore, the plain strain model is suitable for this issue. The size of this numerical model is 60D in width and 30D in depth, which is big enough to avoid the boundary effect.…”

Section: Problem Definitionmentioning

confidence: 99%

“…Additionally, the soil obeys the Mohr-Coulomb yield criterion and associated flow rule with cohesion c, internal friction angle ϕ and unit weight γ. Following previous studies [29], the above parameters have the following values: ϕ = 5 , 20 • ; γD/c = 0 and 1. The numerical model is a rigid half space, and the top surface is free.…”

Section: Problem Definitionmentioning

confidence: 99%

“…Recently, Zhang et al [25,26] and Yang et al [27,28] used the upper bound finite element method to propose sensitivity analyses of double tunnels with different shapes, including pure circular, horseshoe and elliptical tunnels. Additionally, adaptive finite element limit analysis (AFELA) was used by Xiao et al [29] to investigate the stability of double tunnels in c-ϕ soil at different depths; then, the cases of tunnels in rock mass were considered. In recent years, owing to the frequent earthquakes around the world (e.g., EI Centro, Wenchuan, Loma Prieta, Ancona and Fukushima earthquakes, etc.…”

Section: Introductionmentioning

confidence: 99%

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Seismic Stability of Dual Tunnels in Cohesive–Frictional Soil Subjected to Surcharge Loading

Zeng

2022

Applied Sciences

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In this study, a self-developed adaptive finite element limit analysis (AFELA) code was adopted to explore the stability of dual tunnels in cohesive–frictional soil subjected to surcharge loading and seismic action. Parametric studies of different influential factors, including the depth of tunnels, horizontal distance between tunnels, seismic acceleration coefficient, unit weight, cohesion and internal friction angle of soils, were conducted using the AFELA code. An adaptive meshing technique was adopted for optimal accuracy and efficiency, and a pseudostatic method was used to simulate the seismic action. Strict upper bound (UB) and lower bound (LB) results with relative errors of less than 7% were acquired. Detailed design tables were presented to facilitate the engineering design, and three typical failure patterns, including single side-wall failure, half-cross-shaped failure and cross-shaped failure, corresponding to different stable levels, were summarized for a deeper insight into how the failure mechanism evolved under different conditions. The results indicated that the variations in soil unit weight and void depth affected the seismic bearing capacity almost linearly. Furthermore, the dual tunnel system is vulnerable to seismic actions, and the stability of tunnels was further undermined by the adverse effects of additional seismic-caused interactions between two adjacent tunnels.

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“…And the effect of voids will vanish once the footing-void distance beyond a critical distance. Xiao et al 2 developed adaptive finite element limit analysis (AFELA) code to investigate the influence of vertical relative distance between the double circular tunnels on the stability, soon afterwards the issue had been extended to the cases of square tunnels in rock mass 17 . In these cases, the assumption of uniform soils or rocks was made for simplification.…”

Section: Introductionmentioning

confidence: 99%

Undrained stability of dual tunnels in layered soils with different strength

Zeng

2022

Sci Rep

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The stability of dual circle tunnels buried in layered soils with different shear strengths was investigated by using finite element limit analysis (FELA). The emphasis of this study is in quantitating that the existing tunnels affects the newly-built one, and design suggestions have been provided especially in the optimum location of construction. By imposing a FELA modelling, the variation trends of undrained bearing capacity with different influential factors, including the horizontal distance, vertical distance, the thickness of the top layer, the shear strength ratio of the layered soil, were further investigated. It is concluded that there exists an inclination-fixed worst-band, in which there would be a worst undrained stability once the bottom tunnel was constructed in the band. It is interested that the inclination seems constant by varying several factors but the horizontal distance would be changed with the soil properties. In addition, three patterns of collapse were summarized.

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Stability of two circular tunnels at different depths in cohesive-frictional soils subjected to surcharge loading

Cited by 28 publications

References 31 publications

Seismic Bearing Capacity of Strip Footings on Cohesive Soil Slopes by Using Adaptive Finite Element Limit Analysis

Seismic Bearing Capacity of Strip Footings on Cohesive Soil Slopes by Using Adaptive Finite Element Limit Analysis

Seismic Stability of Dual Tunnels in Cohesive–Frictional Soil Subjected to Surcharge Loading

Undrained stability of dual tunnels in layered soils with different strength

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