Permeability Evolution of Two-Dimensional Fracture Networks During Shear Under Constant Normal Stiffness Boundary Conditions

Li, Bo; Bao, Ruyi; Wang, Ye; Liu, Richeng; Zhao, Cheng

doi:10.1007/s00603-020-02273-2

Cited by 66 publications

(62 citation statements)

References 79 publications

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“…In recent years, a large number of indoor true triaxial test studies have been conducted [5][6][7][8][9][10][11][12]. For example, He et al [13,14] carried out true triaxial unloading tests on limestone, sandstone, and granite samples in deep high in situ stress areas and obtained their rockburst induction mechanism and failure characteristics.…”

Section: Introductionmentioning

confidence: 99%

Research on Coal Mechanical Properties Based on True Triaxial Loading and Unloading Experiment

Peng

Deng

Ming-hong

et al. 2021

Advances in Civil Engineering

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To study the safety issues caused by coal mine excavation, self-developed simulation of earth interior atmosphere and sound test system was used to perform true triaxial loading and unloading tests of coal. An acoustic emission detection system was used to record the damage evolution trend of coal under different intermediate principal stress states. The experimental results show that in the true triaxial unloading test, as the intermediate principal stress increases, the failure state of coal changes from shear failure to partial shear tension failure, finally leading to overall yield failure. In the stress-strain curves, with the increase in intermediate principal stress, the strain in the direction of intermediate principal stress gradually changes from compression to expansion, and typical expansion occurs. The Mogi–Coulomb strength criterion better reflects the strength failure characteristics of coal during unloading. The stress-acoustic emission diagrams show that the increase in intermediate principal stress causes the internal cracks of the coal to grow unsteadily and exponentially, and the increase in intermediate principal stress makes the coal lose its ability to continue to bear the load. Studying the influence of the intermediate principal stress on the mechanical properties of coal has practical significance for coal mine safety production.

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Section: Introductionmentioning

confidence: 99%

Research on Coal Mechanical Properties Based on True Triaxial Loading and Unloading Experiment

Peng

Deng

Ming-hong

et al. 2021

Advances in Civil Engineering

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“…In addition to minimizing air leakage on the working face, a circulation channel for gas in goaf should also be provided. Negative pressure extraction [20][21][22][23][24][25] is carried out in the construction drainage hole to drain the goaf gas under the effect of the pressure gradient, which provides a circulation channel for the gas in the goaf. When the pumping effect is good, the problem of upper corner gas can be solved well.…”

Section: Roof Directional Long Holementioning

confidence: 99%

Study on Key Parameters of Directional Long Borehole Layout in High‐Gas Working Face

Yan

Wang

Fan

et al. 2021

Shock and Vibration

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This research aims to obtain a new way based on the directional long borehole layout to investigate the gas migration behavior of coal bed methane. In view of the study of the oil-type gas reservoir and the influence range of mining on the working face in the surrounding rock, the paper puts forward the optimization method of the directional long borehole layout of the surrounding rock and the method of the borehole layout with comprehensive consideration of the influence of mining on the failure of the roof and floor and the distribution of surrounding rock gas-bearing reservoirs. The test results showed that the layout horizon of the directional long boreholes is determined, and the layout was within the height range of 20–40 meters, clarified the relationship between the drainage data and the exposure level of the borehole and the layout of the borehole, compared the gas concentration in the upper corner of the working face before and after the drainage, and constructed a three-dimensional comprehensive drainage mode for the high-gassy working face, which provided a worth-promoting method that supports surrounding rock oil-type gas and gas treatment in the high-gas mining area.

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“…Under an uplift load, the soil at the bottom of the caissons is subjected to both axial unloading and cyclic loading superimposed by wind and wave loads, with cyclic loading inevitably leading to strain softening and cumulative cyclic deformation of the soft clay. Most of studies [1][2][3][4][5][6][7][8] have focused on the case where the initial deviatoric stress is greater than or equal to zero but rarely investigated the cyclic cumulation deformation of soft clay during unloading. Additionally, empirical models are mostly used for cyclic accumulation modeling but have difficulty describing soil strain softening, which is a problem shared by element creep models.…”

Section: Introductionmentioning

confidence: 99%

Study on Cyclic Cumulative Deformation Characteristics and the Equivalent Cyclic Creep Model of Soft Clay

Zhu

Dai

Gong

2021

Mathematical Problems in Engineering

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Suction caisson foundations can be used to anchor tension leg platforms. The soil at the bottom of the caisson undergoes both unloading and cyclic loading under wind and wave loads. However, the problem of cyclic cumulative deformation of soft clay under unloading has rarely been addressed. So, the strain cumulative deformation and strain softening characteristics of soft clay are studied by cyclic triaxial tests. The test results show that under low static deviator stress ratios and dynamic deviator stress ratios, the soil has a low level of strain accumulation and softening. As the dynamic deviator stress ratios increase, the cumulative cyclic deformation gradually increases, which rapidly develops in the early stage and tends to stabilize in the later stage. Moreover, the softening index gradually increases and is linearly related to the logarithm of the number of cycles. The cyclic cumulative deformation of the soil increases with increases in unloading stress and dynamic deviator stress, showing a creep characteristic of attenuation and then stabilization. Based on the tests, an equivalent cyclic creep model is established to describe the strain accumulation and softening of soil and verified through comparison with the test results. Then, the model is extended to a three-dimension model, and a finite element subroutine is developed for studying the strain cumulative deformation and strain softening characteristics of soft clay.

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Permeability Evolution of Two-Dimensional Fracture Networks During Shear Under Constant Normal Stiffness Boundary Conditions

Cited by 66 publications

References 79 publications

Research on Coal Mechanical Properties Based on True Triaxial Loading and Unloading Experiment

Research on Coal Mechanical Properties Based on True Triaxial Loading and Unloading Experiment

Study on Key Parameters of Directional Long Borehole Layout in High‐Gas Working Face

Study on Cyclic Cumulative Deformation Characteristics and the Equivalent Cyclic Creep Model of Soft Clay

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