Analytical solution for a circular roadway considering the transient effect of excavation unloading

Feng, Qiang; Jiang, Binsong; Wang, Gang; Chuan-Peng, Hu

doi:10.1016/j.ijmst.2016.05.002

Cited by 16 publications

(4 citation statements)

References 4 publications

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“…Rock mass fracture damage caused by unloading excavation has always been a topic of high consideration in the rock mechanics [1,2]. e rock in the crust is compressed under the action of gravity and tectonic force of the overlying rock mass.…”

Section: Introductionmentioning

confidence: 99%

Effects of the Loading and Unloading Conditions on Crack Propagation in High Composite Slope of Deep Open‐Pit Mine

Chang

Cai

Zhou

et al. 2019

Advances in Civil Engineering

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In the process of open-pit excavation and stacking of dump along the side wall, the rock mass inside the composite slope undergoes complicated loading and unloading effect, which are manifested as triaxial stress → horizontal unloading → axial loading. In this study, a corresponding mechanical model of crack propagation in composite slope under loading and unloading effects was established. The stress-strain curves and deformation characteristics of rock under different stress paths were studied. A series of different tests under unloading pressure condition were carried out to study the behavior of the rock fracture under different confining pressure paths. The results showed that under the same initial stress conditions, the deviator stress required for rock unloading failure was less than that of the conventional triaxial compression. The axial deformation of rock samples was gradually increased with the increase of unloading, and the unloading easily led to rock failure. By analyzing the crack propagation mechanism under loading and unloading stress field, the analytic relation of the limit height of the composite slope with the crack morphology as the variation was determined when crack propagation occurred near the slope surface. This study provides a technical note on local damage and cracks propagation of a fractured rock mass under the loading-unloading effects in high composite slope.

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Section: Introductionmentioning

confidence: 99%

Effects of the Loading and Unloading Conditions on Crack Propagation in High Composite Slope of Deep Open‐Pit Mine

Chang

Cai

Zhou

et al. 2019

Advances in Civil Engineering

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“…Simultaneously, regarding the impact of mining disturbances on the mechanical characteristics of coal‐rock mass, research results have primarily focused on the establishment of surrounding rock damage models and the exploration of damage evolution laws. Feng et al 12 established a model to calculate the damage zone in the surrounding rocks of circular tunnels by took into account the unloading effect during excavation. Wang et al 13 investigated the effect of mining unloading on the damaged zone around the roadway by using borehole photography and ultrasonic testing techniques.…”

Section: Introductionmentioning

confidence: 99%

Study on the evolutionary characteristics of coal burst proneness under the action of multiple mining disturbances

Liu,

Ouyang,

et al. 2023

Energy Science & Engineering

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Coal burst is a serious hazard in deep coal mining. To investigate the coal burst proneness evolution during multiple mining disturbances (MMD), this paper implemented a range of uniaxial cyclic loading–unloading tests coupled with acoustic emission (AE) measurement to simulate the loading–unloading effects of the MMD. The maximum load was used to simulate the highest load that the coal has endured in history, the loading–unloading rate was used to simulate the mining speed, and the loading–unloading cycles were used to simulate the number of mining disturbances. Finally, the burst proneness indexes of the damaged coal sample are measured and compared with the origin coal sample. Analysis on the experiment results suggest that, the burst proneness increases when the maximum load is 30% of the uniaxial compressive strength (UCS), interestingly, when the low loading–unloading rate is applied, 50% of the UCS enlarge the burst proneness as well. However, it decreases when the maximum load is 70% of the UCS. Sensitivity analysis indicates that the maximum load, loading–unloading rate, and loading–unloading cycles exhibit decreasing influence sensitivity to the elastic modulus, as well as to the UCS and duration of dynamic fracture. Similarly, the influence sensitivity of maximum load, loading–unloading cycles, and loading–unloading rate to the elastic strain energy index decreases, as well as to the bursting energy index. To ensure the safety of coal mining, it is crucial to avoid the disturbances that would put the coal under low loading and low loading rate.

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“…Deep tunnels are mechanical bodies with complex properties, stress states, and boundary conditions. Researchers at home and abroad have conducted many in-depth studies on the distribution of the stress field and displacement field of tunnel surrounding rock and the supporting structure under different construction methods and supporting types based on theoretical analyses, numerical calculations, and model tests [1][2][3][4][5].Specifically, based on the theoretical analysis method of mathematical mechanics, only the analytical solutions for the stress and displacement field of the tunnel surrounding rock mass with a simple section and under simple support conditions can be obtained [6][7][8]. e numerical analysis method [9][10][11] based on the finite element, finite difference, and discrete element methods provides a powerful tool for the stress analysis of tunnel engineering with complex crosssections and composite supports.…”

Section: Introductionmentioning

confidence: 99%

Study on the Geo‐Stress Loading and Excavation Unloading Devices of the Large‐Scale Photoelastic Model Test for Deep‐Buried Tunnels

Guo

Zhu

Liu

et al. 2021

Shock and Vibration

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At present, theoretical analysis, numerical simulation, and other methods cannot be used to properly solve the problems associated with the stability and bearing capacity of the surrounding rock and its supporting system, the interaction between the supporting structure and surrounding rock, and the sharing role of each supporting structure, all of which commonly occur in deep tunnels. The model test method represented by the photoelastic test is still an important approach to study this kind of problem. In view of the deficiency of the current loading system of the photoelastic model test, we developed a geo-stress loading system for the photoelastic model test, which can simulate the in situ geo-stress environment of unidirectional loading, bidirectional equal pressure, bidirectional unequal pressure, and tridirectional unequal pressure. The universal retaining force loading rod can realize the stability and effective compensation of loading, which is an original design. According to the principle of umbrella-shaped expansion and contraction mechanism, an excavation unloading device for the photoelastic model test is developed, which can realize the simulation of various degrees of displacement release in the excavation process of deep tunnels and other underground projects. The loading simulation test and excavation unloading simulation test show that the geo-stress loading system and excavation unloading device developed in this paper are flexible, exhibit good performance, and can fully achieve their respective test functions. The combination of two devices can compensate for the insufficiency of the current photoelastic model test and will promote the application of photoelastic model tests in underground engineering applications such as deep tunnel projects.

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Analytical solution for a circular roadway considering the transient effect of excavation unloading

Cited by 16 publications

References 4 publications

Effects of the Loading and Unloading Conditions on Crack Propagation in High Composite Slope of Deep Open‐Pit Mine

Effects of the Loading and Unloading Conditions on Crack Propagation in High Composite Slope of Deep Open‐Pit Mine

Study on the evolutionary characteristics of coal burst proneness under the action of multiple mining disturbances

Study on the Geo‐Stress Loading and Excavation Unloading Devices of the Large‐Scale Photoelastic Model Test for Deep‐Buried Tunnels

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