Strainburst process of marble in tunnel-excavation-induced stress path considering intermediate principal stress

Jiang, Bangyou; Gu, Shitan; Wang, Lianguo; Zhang, Guangchao; Li, Wen-shuai

doi:10.1007/s11771-019-4065-z

Cited by 90 publications

(36 citation statements)

References 35 publications

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“…When GER technology is applied under a condition of deep hard roof mining, the lateral immediate roof collapses into the goaf, and the length of the hanging roof gradually increases. Furthermore, the main roof rotary subsides along the fracture line as the working face advanced [19][20][21][22][23]. Under these conditions, it becomes very difficult for the traditional roadway support to resist the large pressures caused by the surrounding rock deformation and lateral roof subsidence, which is destructive to the roadside supports and stability of the roadway.…”

Section: Mechanical Modelmentioning

confidence: 99%

“…Hence, maintenance of the gob-side entry becomes extremely difficult, and large deformation and failure accidents occur occasionally [14][15][16][17][18].Many theoretical studies and field practices on GER technology under deep mining conditions have been completed, and three major advancements should be considered. First, the surrounding rock deformation characteristics and failure evolution law of deep GER are revealed under various geological conditions [19][20][21][22][23]. The roof of the gob-side entry is simplified into a rectangular "superposed stratified plate" structure [24,25], and the concept of the strip segmentation method for the roof load is proposed according to the theory of elastoplastic mechanics.…”

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Roof Cutting Parameters Design for Gob-Side Entry in Deep Coal Mine: A Case Study

et al. 2019

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Roof cutting is an effective technique for controlling the deformation and failure of the surrounding rock in deep gob-side entry. The determination of the roof cutting parameters has become a popular research subject. Initially, two mechanical models are established for the non-roof-cutting and roof-cutting of gob-side entry in deep mining conditions. On this basis, the necessity and significance of roof cutting is revealed by analysing the stress and displacement of roadside prop. The Universal Distinct Element Code numerical simulation model is established to determine the key roof-cutting parameters (cutting angle and cutting height) according to the on-site situation of No. 2415 headentry of the Suncun coal mine, China. The numerical simulation results show that with the cutting angle and height increase, the vertical stress and horizontal displacement of the coal wall first increase and then decrease, as in the case of the vertical stress and displacement of roadside prop. Therefore, the optimum roof cutting parameters are determined as a cutting angle of 70 • and cutting height of 8 m. Finally, a field application was performed at the No. 2415 headentry of the Suncun coal mine. In situ investigations show that after 10 m lagged the working face, the stress and displacement of roadside prop are obviously reduced with the hanging roof smoothly cut down, and they are stable at 19 MPa and 145 mm at 32 m behind the working face, respectively. This indicates that the stability of the surrounding rock was effectively controlled. This research demonstrates that the key parameters determined through a numerical simulation satisfactorily meet the production requirements and provide a reference for ensuring safe production in deep mining conditions. about 100-500 m, the microstructures, basic mechanical characteristics, and engineering responses of coal and rock have changed significantly in response to the "three highs and one disturbance" environment [10][11][12][13]. The main features are that the surrounding rock has a large deformation, high deformation speed, long deformation duration, and rheological characteristics. Hence, maintenance of the gob-side entry becomes extremely difficult, and large deformation and failure accidents occur occasionally [14][15][16][17][18].Many theoretical studies and field practices on GER technology under deep mining conditions have been completed, and three major advancements should be considered. First, the surrounding rock deformation characteristics and failure evolution law of deep GER are revealed under various geological conditions [19][20][21][22][23]. The roof of the gob-side entry is simplified into a rectangular "superposed stratified plate" structure [24,25], and the concept of the strip segmentation method for the roof load is proposed according to the theory of elastoplastic mechanics. On this basis, used a numerical analysis method to identify the influence mechanism of the roof fracture location, roof rotation, and long-term creep of the surrounding rock in deep ...

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Section: Mechanical Modelmentioning

confidence: 99%

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confidence: 99%

Roof Cutting Parameters Design for Gob-Side Entry in Deep Coal Mine: A Case Study

et al. 2019

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“…Compared with shallow or medium‐buried depth mining conditions, the stresses and geological environments become very complicated in deep coal mines. Affected by the “three highs and one disturbance” environment, microstructures, basic mechanical characteristics and engineering responses of coal and rock have changed significantly. It becomes very difficult for traditional roadside supports to bear the tremendous pressure caused by hanging roof subsidence.…”

Section: Introductionmentioning

confidence: 99%

An innovative approach for gob‐side entry retaining in deep coal mines: A case study

Fan

Liu

Tan

et al. 2019

Energy Science & Engineering

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Due to the complex geostress and mining conditions in the coal seam with depth of 800 m, stability of surrounding rock for gob‐side entry retaining is very difficult to achieve. In this paper, we firstly propose an innovative bolt‐grouting controlled roof‐cutting for gob‐side entry retaining (BCR‐GER) approach for deep coal mines. Secondly, a mechanical model of “surrounding rock‐supporting body” for BCR‐GER is constructed, which consists of coal wall, roadside props, and gangues in gob (the whole supporting body). Thirdly, the key parameters (ie, cutting height, cutting angle, grouting cable length, and row of roadside props) are designed. Finally, field practice was applied at the No. 31120 haulage roadway of the Suncun coal mine in China, and in situ investigations were conducted for verification. Field measurement results show that maximum convergences of roof‐to‐floor and side‐to‐side were 264 mm and 113 mm, respectively. What is more, the maximum support resistance of roadside props was reduced by approximately 58%. The deformation and failure of surrounding rock were effectively controlled, and the pressure on roadside props was greatly reduced. This research fully considers the bearing properties of gangues in gob, eliminates the secondary disasters caused by borehole blasting, and provides guidance and reference for deep surrounding rock control of the same or similar gob‐side entry.

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“…A rock burst is a common dynamic disaster often accompanied by sudden, quick, and violent ejection of coal or rock during coal excavation that happens in complex ways under special conditions . Many case studies have revealed that the failure of the layer‐crack structure is closely related to rock burst occurrence, especially for brittle rock or coal mass, as shown in Figure . A layer‐crack structure refers to coal or rock rib cut by macrotensile cracks parallel or subparallel to the rib surface at a certain depth due to excavation unloading.…”

Section: Introductionmentioning

confidence: 99%

Experimental study on the failure mechanism of layer‐crack structure

Guo

Tan

et al. 2019

Energy Science & Engineering

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Field investigations have proven that layer‐crack structures make an essential contribution to rock burst occurrence in brittle coal or rock mass. This paper first studies the mechanical behavior of layer‐crack red sandstone specimens with different geometric configurations of vertical fissures (ie, fissure width, fissure length, and fissure number) through uniaxial compression and Brazilian tests. Then, the digital speckle correlation method (DSCM) and acoustic emission (AE) technique are used to record the deformation and failure processes. Finally, the failure mechanisms of the layer‐crack structure are presented and discussed. Under compressive conditions, the failure process can be divided into compatible support, incompatible support, and postpeak unstable failure stages. An increase in fissure width, as well as fissure length or number, causes an increase in the inner damage accumulation and a decrease in the stiffness coefficient by decreasing the strain of the compatible support stage. Thus, the bearing capacity of the layer‐crack structure is weakened. Under tensile conditions, the tensile ability decreases linearly as the fissure length increases, but the vertical pressure acting on the fissure increases linearly as the fissure width increases. Thus, the tensile strength of the layer‐crack structure decreases as the fissure length (or width) increases.

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Strainburst process of marble in tunnel-excavation-induced stress path considering intermediate principal stress

Cited by 90 publications

References 35 publications

Roof Cutting Parameters Design for Gob-Side Entry in Deep Coal Mine: A Case Study

Roof Cutting Parameters Design for Gob-Side Entry in Deep Coal Mine: A Case Study

An innovative approach for gob‐side entry retaining in deep coal mines: A case study

Experimental study on the failure mechanism of layer‐crack structure

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