Computational method of large deformation and its application in deep mining tunnel

Wang, Mingyang; Zhang, Ning; Li, Jie; Ma, Linjian; Fan, Pengxian

doi:10.1016/j.tust.2015.06.006

Cited by 38 publications

(21 citation statements)

References 12 publications

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“…When σ h0 /σ v0 ≥ 1.00, an increase in σ a0 significantly increases the roof subsidence, and the larger σ h0 /σ v0 and σ a0 /σ v0 are, the more significant the effect, which is consistent with the conclusions of Section 2.2, Figure 4d and Equation (10). In addition, the plastic zone depth and roof subsidence results further increase compared with those considering only strain softening, with maxima of 6.89 m and 42.91 cm, respectively, which is more consistent with reality [2,34].…”

Section: Analysis Of the Roof Subsidence And Plastic Zone Depthsupporting

confidence: 87%

“…subsidence only when σh0/σv0 = 0.5 and σa0/σv0 > 1.00; the other schemes have little effect. In addition, the plastic zone depths are shallow, and the maximum plastic zone depth is only 1.78 m; the roof subsidence results are very small, and the maximum roof subsidence is only 2.41 cm, which is inconsistent with the observed severe failure and large deformation of the surrounding rock of deep tunnels [2,34]. When considering only dilatancy, the variations in the plastic zone depth and roof subsidence are similar to those of the perfectly elastoplastic model, but the effect of σa0 on the roof subsidence is more obvious, which is consistent with the conclusions of Section 2.2, Figure 4b and Equation (8).…”

Section: Analysis Of the Roof Subsidence And Plastic Zone Depthmentioning

confidence: 76%

“…In the case of a large difference between σ a0 and the in-plane in-situ stress, σ a will be σ 1 or σ 3 at the initial yield of the surrounding rock [8,9]. According to Equations (1) and (2), σ a will control the failure of the surrounding rock and change the directions of the plastic flow (the axial plastic principal strain increment ∆ε Strain softening leads to degradation of the surrounding rock and contraction of the yield surface, which amplifies the effect of σ a0 . In a strain softening model, the strength parameters are usually defined as functions of the plastic shear strain γ p , but the definitions of γ p are not standardized.…”

Section: When σ a Is σ 1 Or σ 3 At The Initial Yieldmentioning

confidence: 99%

“…Energies 2020, 13, x FOR PEER REVIEW 9 of 14 subsidence only when σh0/σv0 = 0.5 and σa0/σv0 > 1.00; the other schemes have little effect. In addition, the plastic zone depths are shallow, and the maximum plastic zone depth is only 1.78 m; the roof subsidence results are very small, and the maximum roof subsidence is only 2.41 cm, which is inconsistent with the observed severe failure and large deformation of the surrounding rock of deep tunnels [2,34].…”

Section: Analysis Of the Roof Subsidence And Plastic Zone Depthmentioning

confidence: 99%

“…Mineral resources are an important source of energy, and their development is shifting to deeper areas [1][2][3], increasing the depths of the tunnels excavated for the exploitation of mineral resources. Statistically, deep tunnels account for approximately 30% of the tunnels constructed each year, and 70% of these tunnels will need to be repaired owing to large deformations of the surrounding rock masses under high in-situ stress conditions, which greatly increases costs [4].…”

Section: Introductionmentioning

confidence: 99%

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Effect of Axial In-Situ Stress in Deep Tunnel Analysis Considering Strain Softening and Dilatancy

Liu

Lü

et al. 2020

Energies

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In many previous tunnel analyses, the axial in-situ stress was ignored. In this work, its effect on the deformation and failure of the surrounding rock of a deep tunnel was revealed, considering the objective strain softening and dilatancy behavior of the surrounding rock. Analysis based on the incremental plastic flow theory was conducted, and C++ was used to write a constitutive model for numerical simulation to verify and further analyze this effect. Then, the results were validated by the field monitoring data of a coal mine gateway. Results show that the effect of the axial in-situ stress σa0 is more significant when strain softening is considered, compared with the results of a perfectly elastoplastic model. When the axial stress σa is σ1 or σ3 at the initial yield, an increase or decrease in σa0 intensifies the deformation and failure of the surrounding rock. When σa is σ2 at the initial yield, 3D plastic flow partly controlled by σa may occur, and an increase in σa0 intensifies the deformation and failure of the surrounding rock. The effect of σa0 will be amplified by considering dilatancy. Considering both strain softening and dilatancy, when σa0 is close to the tangential in-situ stress σt0 or significantly greater than σt0 (1.5 times), σa will be σ2 or σ1 at the initial yield, and then 3D plastic flow will occur. In the deformation prediction and support design of a deep tunnel, σa0 should not be ignored, and the strain softening and dilatancy behavior of the surrounding rock should be accurately considered.

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Section: Analysis Of the Roof Subsidence And Plastic Zone Depthsupporting

confidence: 87%

Section: Analysis Of the Roof Subsidence And Plastic Zone Depthmentioning

confidence: 76%

Section: When σ a Is σ 1 Or σ 3 At The Initial Yieldmentioning

confidence: 99%

Section: Analysis Of the Roof Subsidence And Plastic Zone Depthmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Axial In-Situ Stress in Deep Tunnel Analysis Considering Strain Softening and Dilatancy

Liu

Lü

et al. 2020

Energies

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A viscoelastic–plastic constitutive model incorporating creep initiation stress for surrounding rock in deep roadways and its practical application

Kang,

Gong,

et al. 2024

Energy Science & Engineering

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With the increasing depth of engineering in rock masses, the issue of significant rheological deformation becomes notably prominent. To accurately characterize the deformation and failure behavior of the surrounding rock near the goaf in deep small coal pillars, we have developed a viscoelastic–plastic constitutive model that takes into account the initial stress associated with creep. This model builds upon an existing viscoelastic–plastic constitutive framework and is implemented numerically using C++ in the FLAC3D. The Oedometer test method is used to check the creep components and the calculated parameter (η/G) ensure convergence of numerical operations. We conducted both pre‐improvement and post‐improvement tests of the constitutive model in a simple numerical analysis of roadways. The enhanced model demonstrates improved accuracy in deviational stress calculations and proves suitable for modeling deep, soft roadways. Furthermore, we applied the improved model to simulate actual working conditions at Zhaozhuang Mine, where mining operations near the working face induce a fracture zone of approximately 3 m in the small coal pillar located at the goaf's edge. The new model closely aligns with the observed results, further validating its suitability for tunneling along the goaf. Tunneling and mining activities result in significant deformation at various locations, including the shoulder socket of the working face, the top angle of the coal pillar, and the bottom angle of the floor. The crushing zone at the working face extends up to 4 m. Rheological effects transform the triangular elastic core, from its original high‐pressure elastic state to a fracture and plastic zone in the deep coal. Stress in deep coal is transmitted along the triangular elastic core. Numerical simulation results closely match the excavation profile of the tunneling, providing valuable insights into the impact of mining activities. This study can provide reference for deformation of similar geological conditions and engineering situation.

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Transfer and dissipation of strain energy in surrounding rock of deep roadway considering strain softening and dilatancy

Liu

Lü

et al. 2020

Energy Science & Engineering

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In this study, the transfer and dissipation of strain energy in the surrounding rock of a deep roadway were analyzed, considering the objective strain softening and dilatancy behaviors. The strain energy increment was decomposed, and its variation was analyzed based on the incremental plastic flow theory; then, a numerical simulation was conducted for verification and further analysis. The results were verified by the field monitoring data of a coal mine gateway. The results show that in the elastic stage, the volumetric elastic strain energy density Uev decreases, while the shear elastic strain energy density Ues increases. In the plastic stage, both Uev and Ues decrease. The volumetric plastic strain energy density Upv is negative, and its absolute value increases, leading to strain energy accumulation. In contrast, the shear plastic strain energy density Ups is positive and increases, leading to strain energy dissipation. Considering strain softening, the elastic strain energy decreases, the plastic strain energy increases, and the region of strain energy dissipation expands. Considering dilatancy, the plastic strain energy varies more significantly, and the effect of strain softening is amplified. The strain energy is transferred from the deep part to the shallow part of the elastic zone and then to the plastic zone. The preexisting and input strain energies in the plastic zone are transformed into considerable amounts of plastic strain energy and then dissipated. Thereafter, a significant plastic strain appears, leading to the large deformation of the surrounding rock.

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Computational method of large deformation and its application in deep mining tunnel

Cited by 38 publications

References 12 publications

Effect of Axial In-Situ Stress in Deep Tunnel Analysis Considering Strain Softening and Dilatancy

Effect of Axial In-Situ Stress in Deep Tunnel Analysis Considering Strain Softening and Dilatancy

A viscoelastic–plastic constitutive model incorporating creep initiation stress for surrounding rock in deep roadways and its practical application

Transfer and dissipation of strain energy in surrounding rock of deep roadway considering strain softening and dilatancy

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