Determination of Strength and Deformation Properties of Columnar Jointed Rock Mass Using Physical Model Tests

Lin, Zhengzhong; Xu, Weiya; Wang, Wei; Wang, Huanling; Wang, Rubin; Ji, Hua; Zhang, Jiuchang

doi:10.1007/s12205-018-0257-6

Cited by 24 publications

(7 citation statements)

References 24 publications

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“…Then, at the middle lower part of the specimen, the fractured zone further develops and the fracturing is intensified. Lin et al (2018) studied the shape effect of CJRMs with transverse joints under uniaxial compression by the experimental tests and analyzed the strength anisotropy and fracture mode. But the progressive fracture process of their specimens was not presented, and the influence of confining pressure was not considered in their study.…”

Section: Analysis Of Shape Effect Of Cjbs With Transverse Jointsmentioning

confidence: 99%

“…However, the AE characteristics underlying the fracture process of CJRMs were not studied. Lin et al (2018) analyzed the shape effect of CJRM specimens with transverse joints by laboratory physical experiments and obtained the curves of uniaxial compressive strengths (UCSs) with various shapes and column dip angles, but the energy evolution and the influence of lateral pressure were not considered. Overall, the physical tests have obtained valuable research results on the understanding of mechanical properties of CJRMs.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Investigation on Anisotropy and Shape Effect of Mechanical Properties of Columnar Jointed Basalts Containing Transverse Joints

2022

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We studied the non-linear mechanical response and failure mechanism of columnar jointed basalts (CJBs) with transverse joints by modeling meso-mechanics, statistical damage theory and continuum mechanics. The anisotropy and shape effect of CJBs with transverse joints were captured under different lateral pressures. The digital images were transformed into heterogeneous element meshes, and the gradual fracturing process and various failure modes of CJBs were reproduced. The compressive strength (CS) and equivalent deformation modulus (EDM) of CJBs parallel and perpendicular to the column axis were studied. The results show that the U-shaped CS curve of CJB appears as the column dip angle increases, and the CS is obviously improved as the lateral pressure increases when the column dip angle is 0°–90°. When the shape of CJB changes from 6 m × 3 m, 3 m × 3 m to 1.5 m × 3 m, the CS continues to increase. Meanwhile, the transverse joints are proven to be critical for determining the mechanical properties of CJBs at the certain dip angles of columns. However, the high lateral pressure can reduce the CS difference between the CJBs with and without the transverse joints. Besides, as the elastic modulus of joints rises, the CS will grow up, and the EDM will increase first and then almost remain at the same level. The coefficient of rock residual strength has a great influence on the CS at the certain dip angles of columns. Additionally, the model boundary significantly affects the anisotropy and shape effect of mechanical properties of CJBs under compression. These conclusions will improve our knowledge of the failure mechanisms and failure patterns of CJBs containing transverse joints.

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Section: Analysis Of Shape Effect Of Cjbs With Transverse Jointsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical Investigation on Anisotropy and Shape Effect of Mechanical Properties of Columnar Jointed Basalts Containing Transverse Joints

2022

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“…The diameters of columns are mainly in the range of 13-25 cm, and the aspect ratios are in the range of 2-5 [17]. 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.…”

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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“…The results show that the failure mode of rock mass is mainly determined by the joint direction and step angle, and the joint dip angle is the parameter that has the greatest influence on the properties of rock mass. Lin et al [3] conducted uniaxial compression tests on physical model samples with different angles of columnar joints and analyzed the strength characteristics and deformation modulus of columnar jointed rock mass. Yang et al [4,5] analyzed the failure characteristics and crack propagation law of discontinuous jointed rock mass with holes.…”

Section: Introductionmentioning

confidence: 99%

Study on Influence of Joint Distribution on Surrounding Rock Failure of an Underground Tunnel

2021

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Due to geological structure and artificial disturbance, a large number of joints and fissures are formed in the surrounding rock of an underground tunnel. In order to study the influence of joints on the failure characteristics of tunnels, three test schemes with different joint lengths, joint spacing, and joint positions are designed. The results show that the bearing capacity of the tunnel decreases with the increase in the joint length. With the increase in joint spacing, the bearing capacity of the tunnel decreases first and then increases. The crack propagation law of the three test schemes has experienced four stages: no crack, crack initiation, crack rapid development, and crack gradual reduction. The location of joints has the greatest influence on the failure mode of the tunnel. The crack is most likely to appear at the top of the tunnel and expand along the joint, mainly because it is easy to form tensile stress at the top of the tunnel and compressive stress concentration at the joint tip. Therefore, when excavating the tunnel in the underground space, the influence of joints on the tunnel should be considered. Analyzing the relationship between the tunnel and joints has important practical guiding significance for the control of the surrounding rock of the tunnel. Finally, the failure results of the indoor physical model and numerical model are compared and analyzed. They are in good agreement, which also reflects the rationality of numerical simulation.

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Determination of Strength and Deformation Properties of Columnar Jointed Rock Mass Using Physical Model Tests

Cited by 24 publications

References 24 publications

Numerical Investigation on Anisotropy and Shape Effect of Mechanical Properties of Columnar Jointed Basalts Containing Transverse Joints

Numerical Investigation on Anisotropy and Shape Effect of Mechanical Properties of Columnar Jointed Basalts Containing Transverse Joints

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

Study on Influence of Joint Distribution on Surrounding Rock Failure of an Underground Tunnel

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