Investigation into the gas adsorption-loading coupling damage constitutive model of coal rock

The coal seam and the roof of the roadway bear loads together in the underground engineering of coal mine. Especially for the roadway driven along the roof, its deformation is completely different from that arranged in the complete rock stratum. Accurately knowing the mechanical mechanism of coal-rock combined body can help understand the deformation and failure modes of such roadways. This article started with tests of coal-rock combined samples with different height ratios, based on the test results, a strain softening damage constitutive model of coal-rock combined body and a method for solving the parameters of the model were proposed, and the influence of the model parameters was discussed. The test results show that the stress peak value and residual strength of the coal-rock combined samples are negatively correlated with the proportion of coal in the coal-rock combined samples, and have a positive correlation with the confining pressure. The damage constitutive model fitted the test curve well. The model can accurately describe the stress-strain curve of coal-rock combined samples, and can reflect the influence of different height ratios of coal and rock samples and confining pressures. The effects of model parameters were discussed based on the damage constitutive model, which are expected to be widely used in underground engineering.

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Analysis of Acoustic Emission Characteristics and Damage Constitutive Model of Coal-Rock Combined Body Based on Particle Flow Code

Symmetry ◽

10.3390/sym11081040 ◽

2019 ◽

Vol 11 (8) ◽

pp. 1040 ◽

Cited By ~ 8

Author(s):

Wanrong Liu ◽

Wei Yuan ◽

Yatao Yan ◽

Xiao Wang

Keyword(s):

Acoustic Emission ◽

Constitutive Model ◽

Particle Flow ◽

Particle Flow Code ◽

Emission Characteristics ◽

Damage Constitutive Model ◽

Coal Rock ◽

Three Stages ◽

Two Stages ◽

Stable Stage

In this manuscript, the numerical coal-rock combined bodies with different height ratios of rock part to coal-rock combined body (HRRC) were established by particle flow code (PFC) firstly, and then the influence of different HRRC on mechanical properties and numerical acoustic emission (AE) characteristics of coal-rock combined bodies were investigated. Finally, the damage constitutive model of the coal-rock combined body was discussed. The research results show that with the increase of the HRRC, the UCS and the elastic modulus (E) of the combined coal-rock bodies increased. The failure of coal-rock combined bodies is mainly focused on the coal body. The evolution law of AE hits of coal-rock combined bodies have three stages, named stable stage, rapid ascending stage, and rapid descending stage. The damage variable curves of coal-rock combined body have two stages, named slowly damage stage and sharply damage stage. The damage constitutive relation based on AE hits can well reflect the stress-strain relationships with a lower HRRC. However, for a higher HRRC, the damage constitutive equation is not accurately and the damage of the rock part in the coal-rock-combined body should be considered.

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A Novel Damage Model for Strata Layers and Coal Mass

Energies ◽

10.3390/en13081928 ◽

2020 ◽

Vol 13 (8) ◽

pp. 1928 ◽

Cited By ~ 2

Author(s):

Faham Tahmasebinia ◽

Chengguo Zhang ◽

Ismet Canbulat ◽

Samad Sepasgozar ◽

Serkan Saydam

Keyword(s):

Constitutive Model ◽

Strain Energy ◽

Damage Model ◽

Rock Joint ◽

Coal Mass ◽

Stored Energy ◽

Rock Interaction ◽

Geological Factors ◽

Coal Rock ◽

Joint Quality

Coal burst occurrences are affected by a range of mining and geological factors. Excessive slipping between the strata layers may release a considerable amount of strain energy, which can be destructive. A competent strata is also more vulnerable to riveting a large amount of strain energy. If the stored energy in the rigid roof reaches a certain level, it will be released suddenly which can create a serious dynamic reaction leading to coal burst incidents. In this paper, a new damage model based on the modified thermomechanical continuum constitutive model in coal mass and the contact layers between the rock and coal mass is proposed. The original continuum constitutive model was initially developed for the cemented granular materials. The application of the modified continuum constitutive model is the key aspect to understand the momentum energy between the coal–rock interactions. The transformed energy between the coal mass and different strata layers will be analytically demonstrated as a function of the rock/joint quality interaction conditions. The failure and post failure in the coal mass and coal–rock joint interaction will be classified by the coal mass crushing, coal–rock interaction damage and fragment reorganisation. The outcomes of this paper will help to forecast the possibility of the coal burst occurrence based on the interaction between the coal mass and the strata layers in a coal mine.

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