Compression–shear strength criterion of coal–rock combination model considering interface effect

Zhao, Zenghui; Wang, Weiming; Wang, Lihua; Dai, Chunhui

doi:10.1016/j.tust.2015.01.007

Cited by 110 publications

(48 citation statements)

References 16 publications

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“…During the loading process, the axial stress loaded on the coal elements and rock elements is same [2,15]. Due to differences in the elastic modulus (E), a completely different deformation pattern is exhibited by the coal elements and rock elements in sandwiched specimens [14,15]. In the present study, the elastic modulus of coal elements was less than that of rock elements.…”

Section: Unbalanced Deformation Characteristics Of Coal Elements and mentioning

confidence: 51%

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Experimental Investigations on the Progressive Failure Characteristics of a Sandwiched Coal-Rock System Under Uniaxial Compression

et al. 2019

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Overlapped residual coal pillars, together with the surrounding rock strata, play a combined bearing role in ultra-close multiple seam mining. Global stability of the whole bearing system is significant for the mining design, construction, and operation. Laboratory uniaxial compressive experiments for different kinds of sandwiched coal-rock specimens are carried out to investigate the progressive failure characteristics and mechanisms. Results show that: (1) The mechanical behavior of the sandwiched coal-rock specimen is mainly divided into four stages during the failure process. The response of the electrical resistivity and the evolution of acoustic emission (AE) energy are in good agreement with the mechanical behaviors at different stages, which are a reflection of the global failure characteristics of sandwiched specimens. (2) The distribution of AE events and the development of local strain can provide further insight into the local failure characteristics of coal elements or rock elements in sandwiched specimens. AE events are more likely to be generated in coal elements, which can propagate across coal-rock interfaces and induce damage to rock elements in a certain area. Similarly, the unbalanced deformation characteristics of coal elements and rock elements are apparently revealed in the progressive failure process. (3) Progressive failure of a sandwiched coal-rock specimen is closely associated with the interactions between the coal elements and rock elements. Initial failure usually appears in the coal elements. At this process, the recovery of elastic deformation and the output of strain energy are observed in the rock elements, which can accelerate the rupture of coal elements. In turn, the dynamic fracture energy generated in the rupture process of coal elements can propagate into rock elements and induce damage to rock elements a certain area. (4) The experimental results are helpful for maintaining the long-term stability of a sandwiched coal-rock system in ultra-close multiple seam mining.

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Section: Unbalanced Deformation Characteristics Of Coal Elements and mentioning

confidence: 51%

“…Previous studies showed that coal elements are usually the main rupture damage elements, while rock elements are rarely damaged [14,17]. This is because the UCS of rock elements in these literatures was significantly more than that of coal elements.…”

Section: Induced Damage Mechanism Of Rock Elementsmentioning

confidence: 94%

Experimental Investigations on the Progressive Failure Characteristics of a Sandwiched Coal-Rock System Under Uniaxial Compression

et al. 2019

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“…We now define the stress concentration factor k=2, overlying rock formation gravity =18 kN/m 3 , coal seam Poisson's ratio ] m =0.32, and buried depth H=100-500 m. According to the geological exploration data of weakly cemented soft rock, the limit equilibrium zone width is analyzed using three groups of parameters, as seen in Table 1 [3,4,32]. Table 1 is displayed in Figure 7.…”

Section: An Analysis Of Factors Influencing the Limit Equilibriummentioning

confidence: 99%

“…The weakly cemented soft rocks, e.g., Cretaceous and Jurassic mudstone, argillaceous siltstone, sandstone, and silt, are widely distributed in Xinjiang, Gansu, Ningxia, western Inner Mongolia, and other areas in western China. The unique physical and mechanical properties of weakly cemented soft rocks are formed in western China due to its special geographical and climate conditions, sedimentary process, and geological conditions, and the rocks are characterized by a low strength, poor cementation, possible weathering, possible argillization and disintegration when encountering water, unstable mechanical properties, and large areas of disturbance, and quick deformation in the surrounding rock after the coal seam has been excavated, resulting in frequent engineering accidents or disasters, such as a large caving in the roof and high walls, and serious floor heave, all of which can cause considerable economic losses and threats to the security of energy engineering construction in western China [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Prediction Model of Failure Zone in Roadway Sidewall considering the Lithologic Effect of Rock Formation

Zhao

Chen

et al. 2018

Mathematical Problems in Engineering

Self Cite

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Coal seam damage area and its stress distribution law in roadway with medium thickness or extrathick coal seam are important issues for understanding the instability mechanism of roadway surrounding rock in weakly cemented soft rock strata in western China. Firstly, a variable parameter microelement analysis model is established based on the assumption of a plane stress integrating with the coal seam-rock’s interface and the rock formation on both sides; moreover, a formula is established by the strain compatibility relationship to express the state of stress in rock bodies on both sides of the interface. Then, a method for calculating the stress limit equilibrium zone width of the coal side and regional stress distribution is presented, which considers the coupling effect of the coal side-rock formation and is based on the loose medium limit equilibrium theory. Finally, the validity of the model is verified through a comparison with previous research and by being applied to an engineering example. The results show the following: (1) the interface adhesion effect results in an abrupt change of the stress state of both the rock formation and coal seam and is related to their deformation parameters; i.e., there is a coupling effect; (2) the limit equilibrium zone width is not only related to the buried depth of the roadway, excavated coal seam thickness, coal seam strength parameters, stress concentration factor, lateral pressure coefficient, and supporting strength of the side of the roadway, but it also has an effect on the aforementioned coupling effect; (3) due to the roof-coal seam-floor comprehensive structural effect, the model presented in this paper is applicable to both the coal seam failure and the failure along the coal seam-rock’s interface.

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“…Zhao et al pointed out that the coal-rock combination with weak interface trended to isotropic rock when the confining pressure is raised to a specific value [14]. Shen et al indicated that the side abutment pressure could result in a relative displacement for entry roof with the weak plane [2,15].…”

Section: Introductionmentioning

confidence: 99%

A New Closed‐Form Solution of the Side Abutment Pressure Distribution of Roadway

Liu

Zhang

2018

Advances in Civil Engineering

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Instability of coal wall is one of the hot-button and difficult issues in the study of coal mine ground control. e shallow side coal of roadway in the coal measures is usually weak and consequently easy to bring about failure. Hence, the side abutment pressure redistributes and dramatically influences the roadway stability. Since the previous closed-form solutions of the side abutment pressure do not take into account all the necessary parameters which include the properties of the coal and the interface between coal and roof/floor, the roadway height, and the support strength, a mechanical model is established based on the equilibrium of the plastic zone, and a new closed-form solution is derived in this paper. Moreover, a numerical investigation is conducted to validate the accuracy of the closed-form solution. e numerical results of the side abutment pressure distribution are in good agreement with the closed-form solution. Afterwards, a parametric analysis of the width of the plastic zone is carried out, and the results show that the width of the plastic zone is nearly negatively linearly correlated with the friction angle and the cohesion of the coal, the interfacial cohesion, and the support strength. By contrast, it is positively linearly correlated with the roadway height and negatively exponentially correlated with the interfacial friction angle. e results obtained in the present study could be useful for the evaluation process of roadway stability.

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Compression–shear strength criterion of coal–rock combination model considering interface effect

Cited by 110 publications

References 16 publications

Experimental Investigations on the Progressive Failure Characteristics of a Sandwiched Coal-Rock System Under Uniaxial Compression

Experimental Investigations on the Progressive Failure Characteristics of a Sandwiched Coal-Rock System Under Uniaxial Compression

Prediction Model of Failure Zone in Roadway Sidewall considering the Lithologic Effect of Rock Formation

A New Closed‐Form Solution of the Side Abutment Pressure Distribution of Roadway

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