An elasto-plastic model for underwater tunnels considering seepage body forces and strain-softening behaviour

Fahimifar, Ahmad; Ghadami, Hamed; Ahmadvand, Masoud

doi:10.1080/19648189.2014.939305

Cited by 23 publications

(9 citation statements)

References 18 publications

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“…Tangential strain ε θ and radial strain ε r are derived from Eqs. (12) and (10). ε θ and ε r satisfied the following equations:…”

Section: Mechanical Model Of Circular Tunnel Surrounding Rocksmentioning

confidence: 96%

“…Surrounding rock displacement u, tangential strain ε θ , radial strain ε r , and equivalent strain ε i are obtained from Eqs. (12) to (15). u, ε θ , ε r , and ε i are expressed as follows:…”

Section: Mechanical Model Of Circular Tunnel Surrounding Rocksmentioning

confidence: 99%

“…Fenner considered tunnel surrounding rocks an ideal elastoplastic medium and initially proposed an elastoplastic analysis for circular tunnel surrounding rocks, which Kastner later revised. After considering the strain softening characteristics to increase the accuracy of solutions, many scholars performed a number of improvements and fresh attempts in the treatment of the surrounding rock constitutive model [7], [8], [9], [10], [11], [12], [13], [14]. For example, Alejano et al [7] presented a more practical elastoplastic analysis by simplifying the surrounding rock constitutive model into a linear "tri-segment" model.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Elastoplastic Analysis of Tunnel Surrounding Rocks based on the Statistical Damage Constitutive Model

Zhu¹,

Yin²,

Li³

et al. 2016

JESTR

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Accurately determining the stress status of surrounding rocks is difficult as stress in surrounding rocks is redistributed after tunneling. A constitutive model selection of surrounding rocks based on the pre-peak strain hardening characteristics of surrounding rocks is considered to further analyze the mechanical characteristics of tunnel surrounding rocks. Theoretical analysis and analytic calculation were conducted on the stress distribution and the deformation characteristics of tunnel surrounding rocks in this study. The evolution laws of stress, as well as the strain of the elastoplastic zone of tunnel surrounding rocks, and the plastic zone radius along with strain hardening and other relevant factors were also analyzed. Results show that, in view of strain hardening, the mechanical characteristics of surrounding rocks increasingly approaches that of reality and the plastic zone radius achieved is larger than the result of the Kastner solution. Moreover, when the strain hardening stage is shortened, the plastic zone radius initially decreases and then slightly increases; tangential strain and displacement increase in varying degrees as the radial strain gradually decreases; tangential stress peak gradually increases and the sudden change of its distribution curve becomes increasingly evident although radial stress changes are less obvious; and sensitivity of the radius and displacement of the surrounding rock plastic zone that support resistance increase with the increase in mining depth. As a result, the research findings solve, to a certain degree, the problem that the constitutive model of surrounding rocks failed to reflect the true characteristics of surrounding rocks, providing the theoretical foundation of stability analysis and supporting the design of tunnel surrounding rocks.

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“…Tangential strain ε θ and radial strain ε r are derived from Eqs. (12) and (10). ε θ and ε r satisfied the following equations:…”

Section: Mechanical Model Of Circular Tunnel Surrounding Rocksmentioning

confidence: 96%

Section: Mechanical Model Of Circular Tunnel Surrounding Rocksmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Elastoplastic Analysis of Tunnel Surrounding Rocks based on the Statistical Damage Constitutive Model

Zhu¹,

Yin²,

Li³

et al. 2016

JESTR

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“…Debernardi et al [15] established a new SHELVIP model, investigated the stress and deformation characteristics of roadway surrounding rock in detail, and analyzed the reasonability of this model according to the stress and deformation characteristics of roadway surrounding rock and shear dilatancy characteristics. Taking moisture-containing roadway as research object, Fahimifar et al [16] considered the influence of pore water pressure on roadways and obtained the elastic-plastic solution of roadway surrounding rock. Zhu et al [17], [18] analyzed the stress distribution and deformation characteristics of roadway surrounding rock given that the surrounding rock was under uniformly distributed stress field and based on stress-hardening characteristics in front of surrounding rock peak.…”

Section: State Of the Artmentioning

confidence: 99%

Elastic-Plastic Analysis of Surrounding Rock in Deep Roadway Considering Shear Dilatancy Property under Non-Uniform Stress Field

Li¹,

Shi²,

Liu³

et al. 2017

JESTR

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The surrounding rock of deep engineering roadway is under the complicated mechanical environment of non-uniform stress distribution, and the stress mechanical model of uniform distribution is obviously different from the surrounding rock of roadway in real stress state. Thus, accurately evaluating the stress and deformation state of surrounding rock is infeasible in non-uniform stress field when employing the mechanical model developed for uniform stress conditions. To reflect the real mechanical state of the roadway surrounding rock accurately and calculate the radius of the plastic zone in roadway surrounding rock precisely, a mechanical model of roadway surrounding rock under non-uniform stress conditions was established in this study based on unified strength theory. One floor roadway of 1231 (1) working face in Panyi coal mine of Huainan coal field was considered as an example. The influences of side pressure coefficient and intermediate principal stress on the scope of the plastic zone in surrounding rock were analyzed. The effect of shear dilatancy property on the deformation and failure process of surrounding rock was discussed, and the field monitoring and verification of the scope of the plastic zone in surrounding rock were conducted on the floor roadways of 1231 (1) and 1252 (1) working face in this mine. Research results indicate that the displacement of the plastic zone enlarges by nearly thrice while the side pressure coefficient increases, and the radius of the plastic zone in roadway surrounding rock in the vertical direction is obviously larger than that in the horizontal direction, which reflects an anisotropic characteristic of the surrounding rock of deep roadway. The displacement of the plastic zone in the surrounding rock enlarges by at least 60% while the shear dilatancy parameter increases, but the morphological change of the plastic zone is minor. Furthermore, the displacement of the plastic zone in the surrounding rock reduces by nearly 35% while the intermediate principal stress increases. Field test results of the scope of the plastic zone in roadway surrounding rock through borehole peering under different side pressure coefficients match well with the results from theoretical calculation, which verifies the applicability and accuracy of the mechanical model of roadway surrounding rock established in this study. The research results can provide theoretical references for stability analysis and support the design of the surrounding rock of deep roadway.

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“…However, the numerical approach of Lee and Pietruszczak (2008) is based on the radial stress reduction in plastic zone. Although the approach of Park et al (2008) is wider used in calculation of ground response curve such as Fahimifar, Ghadami, and Ahmadvand (2015), the approach described by Lee and Pietruszczak (2008) is in better agreement with rigorous approach than the method described by Park et al (2008) and Alejano, Alonso, Rodríguez-Dono, & Fernández-Manín (2010).…”

Section: Introductionmentioning

confidence: 99%

Practical ground response curve considering post-peak rock mass behaviour

Katebian

Molladavoodi

2015

European Journal of Environmental and Civil Engineering

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Analysis of stresses and displacements around circular opening excavated in rock mass has been one of the significant issues in tunnelling. A plastic zone is formed around underground opening as a result of high induced stress magnitudes. The ground response curve is one of the best methods to investigate the tunnel stability that represent the relationship between the decreasing of inner pressure and the increasing of radial displacement of tunnel wall. In recent years, several methods have been suggested for analysis of ground response curve by many researchers, however, some of the analytical solutions that have been presented, are relevant to elastic-perfectly plastic or elastic-brittle-plastic behaviour of rock. But real behaviour of plastic zone is strain softening with variable dilatancy. In this study, it is attempted to take into account the post-peak rock mass behaviour (drop modulus and variable dilation angle) in the stress-based finite difference approximation numerical procedure, so an algorithm is suggested to analyse the tunnel stresses and convergences. In order to verify the proposed algorithm, the results were compared with FLAC numerical solution. For showing the applicability of the proposed algorithm, the Ghomroud tunnel convergence was calculated based on the proposed algorithm and compared with the monitored tunnel convergence. At the end, the effect of various parameters including dilation, critical softening parameter and rock mass quality (GSI) was studied on the tunnel convergence and plastic zone thickness. Based on the obtained results, the higher quality of the rock mass surrounding the tunnel has, the narrower plastic zone forms and the lower tunnel wall converges. Also, the rock mass with higher brittleness means more convergence and wider plastic zone. Furthermore, constant dilation in plastic zone overestimates the tunnel wall convergence.

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An elasto-plastic model for underwater tunnels considering seepage body forces and strain-softening behaviour

Cited by 23 publications

References 18 publications

Elastoplastic Analysis of Tunnel Surrounding Rocks based on the Statistical Damage Constitutive Model

Elastoplastic Analysis of Tunnel Surrounding Rocks based on the Statistical Damage Constitutive Model

Elastic-Plastic Analysis of Surrounding Rock in Deep Roadway Considering Shear Dilatancy Property under Non-Uniform Stress Field

Practical ground response curve considering post-peak rock mass behaviour

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