An Innovative Elastoplastic Analysis for Soft Surrounding Rock considering Supporting Opportunity Based on Drucker‐Prager Strength Criterion

Wang, Rui; Li, Xudong; Bai, Jianbiao; Yan, Shuai; Xu, Jun

doi:10.1155/2021/5555839

Cited by 6 publications

(4 citation statements)

References 25 publications

(28 reference statements)

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“…Owing to the influence of tectonic movement, rock strength and multilayer surrounding rock, the initial in situ stress field is discrete. The maximum horizontal, minimum horizontal and vertical components of the initial in situ stress are unbalanced (Wang et al, 2021). As the mining depth increases, the lateral pressure coefficient gradually decreases, and the ratio of horizontal to vertical in situ stresses is 0.5-2.0 (Kang et al, 2010); however, factors such as tectonic movement, topography, faults and joints can change the in situ stress field and alter the deformation and failure law of the rock mass (Lu et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

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Numerical analysis for tunnelling-induced stress and plastic evolution causing instability of multilayered surrounding rock by varying three-dimensional in situ stresses

Wang,

Feng,

et al. 2023

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PurposeThe induction of geological disasters is predominantly influenced by the dynamic evolution of the stress and plastic zones of the multilayer rock formations surrounding deep-rock roadways, and the behaviours and mechanisms of high in situ stress are key scientific issues related to deep-resource exploitation. The stress environment of deep resources is more complex owing to the influence of several geological factors, such as tectonic movements and landforms. Therefore, in practical engineering, the in situ stress field is in a complex anisotropic three-dimensional state, which may change the deformation and failure law of the surrounding rock. The purpose of this study is to investigate the tunnelling-induced stress and plastic evolution causing instability of multilayered surrounding rock by varying three-dimensional in situ stresses.Design/methodology/approachBased on data from the Yangquan Coal Mine, China, a finite difference model was established, and the elastic-plastic constitutive model and element deletion technology designed in the study were analysed. Gradual tunnelling along the roof and floor of the coal seam was used in the model, which predicted the impact tendency, and compared the results with the impact tendency report to verify the validity of the model. The evolutions of the stress field and plastic zone of the coal roadway in different stress fields were studied by modifying the maximum horizontal in situ stress, minimum horizontal in situ stress and lateral pressure coefficient.FindingsThe results shown that the in situ stress influenced the stress distribution and plastic zone of the surrounding rock. With an increase in the minimum horizontal in situ stress, the vertical in situ stress release area of the roof surrounding rock slowly decreased; the area of vertical in situ stress concentration area of the deep surrounding rock on roadway sides decreased, increased and decreased by turn; the area of roof now-shear failure area first increased and then decreased. With an increase in the lateral pressure coefficient, the area of the horizontal in situ stress release area of the surrounding rock increased; the area of vertical in situ stress release area of the roof and floor surrounding rock first decreased and then increased; the area of deep stress concentration area of roadway sides decreased; and the plastic area of the surrounding rock and the area of now-shear failure first decreased and then increased.Originality/valueThe results obtained in this study are based on actual cases and reveal the evolution law of the disturbing stress and plastic zone of multilayer surrounding rock caused by three-dimensional in situ stress during the excavation of deep rock roadways, which can provide a practical reference for the extraction of deep resources.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical analysis for tunnelling-induced stress and plastic evolution causing instability of multilayered surrounding rock by varying three-dimensional in situ stresses

Wang,

Feng,

et al. 2023

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“…Based on unified strength theory, Liu [17] obtained analytical expressions considering dilation characteristics and intermediate principal stress, but effect of strain softening and seepage were not considered. Considering effects of strain softening, dilatancy and intermediate principal stress, scholars [11,[18][19][20][21] obtained analytic solutions based on different strength criteria, such as generalized spatially mobilized plane criterion, generalized three-dimensional Hoek-Brown criterion, modified Lade criterion and Drucker-Prager criterion, which indicated that intermediate principal stress had influenced on stress distributions, but the seepage effect was not considered. In comparison of four different strength criteria, Pan [12] and Fan [16] analyzed influences of seepage, rock dilatancy and intermediate principal stress, which indicated that the rock dilatancy was related to plastic potential function, but they did not distinguish the strain-softening zone and broken zone.…”

Section: Introductionmentioning

confidence: 99%

A Unified Solution for Surrounding Rock of Roadway Considering Seepage, Dilatancy, Strain-Softening and Intermediate Principal Stress

et al. 2022

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The analytic solution for surrounding rock of roadway is of significance for stability analysis and roadway support. However, analytical solution for surrounding rock of roadway which took influences of water seepage, strain softening, dilatancy and intermediate principal stress all into account did not receive much reporting. To promote research in this aspect, a mechanical model simultaneously considering water seepage, strain softening, rock dilatancy, and intermediate principal stress was established based on porous elastoplastic mechanics, and then unified analytical solution for surrounding rock of roadway was obtained. Based on an example, influences of water seepage, strain softening, rock dilatancy, residual cohesion and intermediate principal stress on surrounding rock of roadway were thoroughly investigated using single factor analysis. The obtained results are as follows: radii of plastic zones and surface displacement of roadway would increase exponentially with water pressure increasing and their magnitudes are greater than corresponding values without water seepage considered; with softening modulus increasing, peak circumferential stress location would slightly shift to deeper surrounding rock, while broken zone radius and surface displacement of roadway would increase in a decay velocity; rock dilatancy has little effect on peak circumferential stress and plastic softening zone radius, while broken zone radius and surface displacement of roadway increase linearly with dilatancy coefficient α1 increasing indicating their magnitudes are overestimated if associated flow rule is adopted; with weighted coefficient increasing, stress components in plastic zones at the same distance from roadway center would increase, while radii of two plastic zones and surface displacement of roadway are reduced, i.e., self-bearing capacity of rock is enhanced considering intermediate principal stress effect compared to Mohr–Coulomb criterion; with residual cohesion increasing, peak circumferential stress remains unchanged, while stress components in plastic zones at the same distance from roadway center would increase and radii of two plastic zones decrease significantly. The above results implicated that water seepage effect should be carefully considered for roadway stability under groundwater environment; strain-softening and flow rule of rock should be reasonably analyzed and chosen to accurately predict surface displacement and broken zone radius of roadway; rock bolt length should be increased with softening modulus increasing, while it can be decreased with intermediate principal stress effect considered; grouting measure is an effective measure to improve roadway stability. In short, the research provides a theoretical basis and some practical engineering implication for roadway support.

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“…The interaction of a tunnel's surrounding rock supports has been a focus of research globally [1][2][3]. The tunnel support structure is complex and difficult to predict, especially for initial support, for which loads originate directly from the surrounding rock that is closely attached to it [4,5].…”

Section: Introductionmentioning

confidence: 99%

Research on the Stress Characteristics of Initial Tunnel Supports Based on Active Load Adjustment

Chen

Fang

2022

Applied Sciences

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Initial tunnel support takes on a critical significance in the stability control of surrounding rocks and the core content of tunnel support design. Its stability and safety are essential to the tunnel. The support load was optimized using the active surrounding rock load intervention scheme in accordance with the section form and bearing characteristics of the support structure. The optimization scheme of active surrounding rock load was obtained by applying active intervention load to the initial support of the tunnel to minimize the peak moment of the support structure. An active adjustment system for tunnel-surrounding rock loads was developed using the function of hydraulic load transfer and transmission combined with load proportion control. Based on the actual project, the implementation effect of the surrounding rock load active intervention scheme was verified by analyzing the measurement results of the supporting structure in the test section and the comparison section. The results suggest that the application of active intervention load can effectively improve the stress state of the tunnel initial support structure, significantly reduce the tunnel surrounding rock bias pressure and the structural peak bending moment, and increase the stability of the support structure. To control the peak moment of the supporting structure, an active intervention method and its implementation scheme for the stress of the tunnel supporting structure were proposed, which reduces the deficiency in which the conventional supporting structure can only passively bear the deformation pressure of the surrounding rock, effectively improves the stress state of the supporting structure, and can provide a reference for the development of novel tunnel supporting forms.

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An Innovative Elastoplastic Analysis for Soft Surrounding Rock considering Supporting Opportunity Based on Drucker‐Prager Strength Criterion

Cited by 6 publications

References 25 publications

Numerical analysis for tunnelling-induced stress and plastic evolution causing instability of multilayered surrounding rock by varying three-dimensional in situ stresses

Numerical analysis for tunnelling-induced stress and plastic evolution causing instability of multilayered surrounding rock by varying three-dimensional in situ stresses

A Unified Solution for Surrounding Rock of Roadway Considering Seepage, Dilatancy, Strain-Softening and Intermediate Principal Stress

Research on the Stress Characteristics of Initial Tunnel Supports Based on Active Load Adjustment

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