Anisotropic constitutive model of pentagonal prism columnar jointed rock mass

Que, Xiangcheng; Zhu, Zhende; Lu, Wenbin

doi:10.1007/s10064-019-01521-2

Cited by 22 publications

(9 citation statements)

References 29 publications

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“…In the fractured rocks, the thickness of the fracture is thinner than that of the entire rock, and the strength is much lower than that of the complete rock. Therefore, its compressive strength along the direction of joint extension is generally ignored, and only its vertical compressive strength is considered [47]. When analyzing the deterioration mechanism and permeability characteristics of the filling fracture under the coupling field, the influence of the stress field perpendicular to the fracture is considered, and water pressure is used as the volume force to calculate the effective stress inside the rock mass, which determines the deterioration degree of the filling fracture.…”

Section: Stress Field Distribution On the Surface Of The Fracture Filmentioning

confidence: 99%

Study on Permeability Characteristics of Rocks with Filling Fractures Under Coupled Stress and Seepage Fields

Zhu

Niu

Que

et al. 2020

Water

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Infilling fractured rock masses are widely distributed in the deeply buried oil reservoirs and surrounding rocks of mine caves. The internal filling material has a great influence on the mechanical properties and seepage characteristics of fractured rock mass. In this paper, through theories and experiments, the mechanism of permeability changes of infilling fractured rock under a coupling condition is studied. In terms of theory, the fracture compaction effect coefficient δ is added to the classical matchstick model, and the volume strain principle is used to propose a permeability model for fractured rock. Furthermore, based on the Hertz contact theory, mineral particles are generalized into rigid spheres, and the mechanism of crack development between mineral particles under seepage pressure is analyzed. In terms of experiment, a true triaxial seepage test was carried out on rock-like specimens to obtain the change law of the permeability characteristics of fractured rock. The test results are largely consistent with the theoretical calculation results of the theoretical model, which verifies the applicability of the model proposed in this paper. After the loading failure of the specimen, the internal filling material was taken out and analyzed, and by observing the distribution of cracks on the surface, it is verified that the seepage pressure promotes the development of cracks in the filling fracture.

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Section: Stress Field Distribution On the Surface Of The Fracture Filmentioning

confidence: 99%

Study on Permeability Characteristics of Rocks with Filling Fractures Under Coupled Stress and Seepage Fields

Zhu

Niu

Que

et al. 2020

Water

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“…For convenience of calculation, the joint arrangement of the Hexagonal prism and the Pentagonal prism model is simplified into a quadrilateral. This arrangement, applying the simplified approach proposed by Que [21], simplifies the geometric elements of the three models into a joint length S 2 parallel to the X axis and a joint width S 1 parallel to the Y axis; the cross-sectional shape of the Pentagonal prism and the Hexagonal prism model is simplified into a quadrilateral. This simplified method will lead to some errors when the variable angle θ 0 for the Pentagonal prism model, but the study by Que proved that this error is extremely small and can be ignored, and when θ = 0, the pentamorphic shape will become rectangular.…”

Section: Establishment Of Permeability Coefficient K Zz Of the Columnmentioning

confidence: 99%

“…It is necessary to fully consider the influence of different cross-section shapes on the seepage characteristics of CJRM. The data comes from Que [21].…”

Section: Introductionmentioning

confidence: 99%

“…In this paper, a stress-dependent columnar joint seepage model is established. The Pentagonal column constitutive model proposed by Que [21] is introduced simultaneously with the Quadrangular prism and the Hexagonal column model. Based on the theory of composite mechanics and Goodman's joint superposition principle, the constitutive model of joints of CJRM is derived on the basis of the Quadrangular prism, the Pentagonal prism and the Hexagonal prism model in The theoretical analytical method provides a convenient and fast way of studying the deformation characteristics of jointed rock masses.…”

Section: Introductionmentioning

confidence: 99%

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Constitutive Model of Stress-Dependent Seepage in Columnar Jointed Rock Mass

2020

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Columnar jointed rock mass (CJRM) is a highly symmetrical natural fractured structure. As the rock mass of the dam foundation of the Baihetan Hydropower Station, the study of its permeability anisotropy is of great significance to engineering safety. Based on the theory of composite mechanics and Goodman’s joint superposition principle, the constitutive model of joints of CJRM is derived according to the Quadrangular prism, the Pentagonal prism and the Hexagonal prism model; combined with Singh’s research results on intermittent joint stress concentration, considering column deflection angles, the joint constitutive model of CJRM in three-dimensional space is established. For the CJRM in the Baihetan dam site area, the Quadrangular prism, the Pentagonal prism and the Hexagonal prism constitutive models were used to calculate the permeability coefficients of CJRM under different deflection angles. The permeability anisotropy characteristics of the three models were compared and verified by numerical simulation results. The results show that the calculation results of the Pentagonal prism model are in good agreement with the numerical simulation results. The variation of permeability coefficient under different confining pressures is compared, and the relationship between permeability coefficient and confining pressure is obtained, which accords with the negative exponential function and conforms to the general rule of joint seepage.

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“…Previous studies on the CJRM were mainly based on the regular 4P-and 6P-CJRM models shown in Figure 2a,b [16,23]. Que [24] proposed a 5P-CJRM model which has the structural characteristics of the above two regular models. As shown in Figure 2c, the 5P-CJRM model not only includes the persistent joints, but also has the interlocking structure.…”

Section: Structural Characteristics Of the Cjrmmentioning

confidence: 99%

Model Test Study on the Anisotropic Characteristics of Columnar Jointed Rock Mass

et al. 2020

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Because of its special structure, the anisotropic properties of columnar jointed rock mass (CJRM) are complicated, which brings difficulty to engineering construction. To comprehensively study the anisotropic characteristics of CJRM, uniaxial compression tests were conducted on artificial CJRM specimens. Quadrangular, pentagonal and hexagonal prism CJRM models were introduced, and the dip direction of the columnar joints was considered. Based on the test results and the structural features of the three CJRM models, the deformation and strength characteristics of CJRM specimens were analyzed and compared. The failure modes and mechanisms of artificial specimens with different dip directions were summarized in accordance with the failure processes and final appearances. Subsequently, the anisotropic degrees of the three CJRM models in the horizontal plane were classified, and their anisotropic characteristics were described. Finally, a simple empirical expression was adopted to estimate the strength and deformation of the CJRM, and the derived equations were used in the Baihetan Hydropower Station project. The calculated values are in good agreement with the existing research results, which reflects the engineering application value of the derived empirical equations.

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Anisotropic constitutive model of pentagonal prism columnar jointed rock mass

Cited by 22 publications

References 29 publications

Study on Permeability Characteristics of Rocks with Filling Fractures Under Coupled Stress and Seepage Fields

Study on Permeability Characteristics of Rocks with Filling Fractures Under Coupled Stress and Seepage Fields

Constitutive Model of Stress-Dependent Seepage in Columnar Jointed Rock Mass

Model Test Study on the Anisotropic Characteristics of Columnar Jointed Rock Mass

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