Simulation test of spalling failure of surrounding rock in rectangular tunnels with different height-to-width ratios

Gong, Fengqiang; Wu, Wuxing; Li, Tianbin

doi:10.1007/s10064-020-01734-w

Cited by 23 publications

(4 citation statements)

References 24 publications

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“…The slabbing failure rock mass consists of a slab fracture structure formed by excavation unloading of intact rock mass, relatively intact rock mass, and massive rock mass, and a natural slab fracture structure formed by long-term geological processes. Due to the difference in output characteristics of the slab fracture rock mass, the rock slab with anti-dip characteristics is prone to toppling deformation and failure, which are common in hydropower, traffic engineering slopes, hydropower buildings, and tunnels (Goodman, 2013). Toppling failure has been reported in more and more situations with the construction of mines, highways, hydropower stations, and so on.…”

Section: Introductionmentioning

confidence: 99%

“…Some scholars analyzed the characteristics of slope rock mass slabbing under different stress modes caused by valley undercutting, excavation, and long-term geological processes from the perspective of supergene transformation and aging deformation (Huang et al, 1994;Tao et al, 2000;Huang, 2008;Huang et al, 2017;Cai et al, 2019;Liang et al, 2022;Li et al, 2022b). The latest research show that a large number of slabbing failures have also emerged in the excavation of underground chambers and tunnels (Du et al, 2016;Gong et al, 2018Gong et al, , 2020Pan et al, 2020;Jiang et al, 2021;He et al, 2022;Tang et al, 2022;Wang et al, 2022). Huang (2008) and Huang et al (2017) proposed the three stages of the development process of high slope and the characteristics of slope stress field with undercutting or excavation unloading, which is of great significance to reveal the causes of rock mass slabbing under stress conditions at different development stages of the slope and also deepen the understanding of rock mass slabbing phenomena exposed by the excavation of deep tunnels and hydropower underground chambers.…”

Section: Introductionmentioning

confidence: 99%

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Mechanical mechanism of rock mass slabbing aggravating toppling failure

Cai

Lu²,

Li³

et al. 2023

Front. Ecol. Evol.

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Many slabbing rock masses have emerged in hydropower slopes and underground engineering, with the construction of basic engineering and resource development projects along the zone of the Belt and Road. The anti-dip slabbing rock mass is prone to toppling and the degree of slabbing controls the development of toppling deformation. There are a few reports on the mechanical mechanism of rock mass toppling deformation after slabbing. Based on the analysis of the genetic conditions of rock mass slabbing, the influence of rock mass after slabbing on toppling deformation was explored by means of the mechanics method. The toppling bending deflection (TBD) and the toppling fracture depth (TFD) were selected as the analysis indexes, and the response regularity of slabbing on toppling rock mass was analyzed with examples. The results show that the width and thickness of the slabbing rock mass become narrower and thinner, the toppling bending deflection (TBD) increases, the toppling fracture depth (TFD) decreases, and the toppling deformation and failure intensify. The TBD is independent of the width of rock mass slabbing under self-weight, and the change of TBD is slow when the slab beam slabbing number (n) of thickness is <4 and fast when the slabbing number is above 4. The first TFD decreases fast when w is <2.0 m and it tends to be stable when w is above 2.0 m. The first TFD reduces relatively fast with the decrease in the thickness (t) of the slab beam. The result of this study can provide a reference for the treatment and evaluation of slabbing rock mass toppling deformation.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mechanical mechanism of rock mass slabbing aggravating toppling failure

Cai

Lu²,

Li³

et al. 2023

Front. Ecol. Evol.

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“…However, many scholars have found deformation behavior in the prefabricated fragments after explosive loading [2][3][4], and brittle materials (such as ceramics, rocks, tungsten alloys, reactive alloys, etc.) would even be fractured during the explosive loading process [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Effect of surface electroplating on fragment deformation behavior subjected to contact explosion

Meng

wang

et al. 2023

Preprint

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Prefabricated fragments can deform or even fracture subjected to contact explosion. Thus, the surface of the prefabricated fragment was electroplated with Ni, in order to change the fragment deformation behavior. The effect of surface electroplating on the fragment deformation behavior under contact explosion was analyzed. Firstly, explosion recovery experiments were carried out on uncoated and coated fragments, and different lining thicknesses were set for comparison. By observing the recovered samples, the deformation behavior of two kinds of samples was found to change after contact explosion: the uncoated fragments were fractured, while the coated fragments maintained integrity. The lining did not change the fragment deformation behavior but could change the degree of deformation. As the thickness of the lining decreased, the degree of fragmentation compression increased. To study this phenomenon, detonation wave theory and shock wave transmission theory in solids were used to calculate the pressure amplitude variation at the far-exploding surface of the fragments. The pressure amplitude of the uncoated samples instantly dropped to zero after the shock wave passed through the far-exploding surface, which resulted in the formation of tensile zone. But the pressure amplitude of the coated samples increased, which transformed the tensile zone into the compression zone, thereby preventing the fracture of the fragment near the far-exploding surface, which was consistent with the test results. Then, microscopic observation of the circumferential direction of the recovered samples showed that the coatings were better than the lining in preventing "weld melting" and fracture phenomena in the radial direction of the fragments. The test results and theories show that the coating can change the deformation behavior of the fragment and prevent the fracture phenomenon of the fragment. The coating also has better protection performance than the lining against contact explosion.

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“…Scholars have also studied the deformation characteristics of rocks surrounding excavated rectangular caverns (tunnels) by theoretical calculation and laboratory experiments. ey have revealed the mechanism by which the spalling phenomenon forms in the sidewalls of rectangular caverns [38][39][40]. Currently, deformation/damage mechanisms, stability analysis, and deformation control in roadway-surrounding rock have mainly been simulated using the finite element, finite difference, and block discrete element methods.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of Damage to Rock Surrounding an Underground Coal Roadway Excavation

Jiang

Wang

Zhao

et al. 2020

Advances in Civil Engineering

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In coal mines, underground roadways are required to transport coal and personnel. Such tunnels can become unstable and hazardous. This study simulates deformation and damage in the rock surrounding a shallow coal seam roadway using particle flow code. A numerical model of particle flow in the surrounding rock was constructed based on field survey and drilling data. Microcharacteristic indices, including stress, displacement, and microcrack fields, were used to study deformation and damage characteristics and mechanisms in the surrounding rocks. The results show that the stress within the rock changed gradually from a vertical stress to a circumferential stress pattern. Stress release led to self-stabilizing diamond-shaped and X-shaped tensile stress distribution patterns after the excavation of the roadway. Cracking increased and eventually formed cut-through cracks as the concentrated stress transferred to greater depths at the sides, forming shear and triangular-shaped failure regions. Overall, the roof and floor were relatively stable, whereas the sidewalls gradually failed. These results provide a reference for the control of rock surrounding roadways in coal mines.

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Simulation test of spalling failure of surrounding rock in rectangular tunnels with different height-to-width ratios

Cited by 23 publications

References 24 publications

Mechanical mechanism of rock mass slabbing aggravating toppling failure

Mechanical mechanism of rock mass slabbing aggravating toppling failure

Effect of surface electroplating on fragment deformation behavior subjected to contact explosion

Numerical Study of Damage to Rock Surrounding an Underground Coal Roadway Excavation

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