The Effect of Joint Dip Angle on the Mechanical Behavior of Infilled Jointed Rock Masses under Uniaxial and Biaxial Compressions

Abstract

Due to the complex formation process of a rock mass, a large number of fissures, joints, faults, other defects exist and the defects commonly contain infilled materials. The jointed rock masses are in a complex geological environment, in which the geometric distribution and the boundary condition can greatly affect the mechanical behavior of the infilled jointed rock mass. In this study, the infilled jointed rock mass specimens with different dip angles are prepared using similar materials, and the uniaxial and biaxial compression tests on the specimens are conducted. The effect of the joint dip angle on the mechanical behavior of the infilled jointed rock mass under uniaxial and biaxial compressions is investigated. The results show that the uniaxial compressive strength shows a W-shaped variation, and the biaxial compressive strength shows a V-shaped variation with an increase in the dip angle. Most of the cracks appear in pairs around the joint and occur symmetrically in a bilateral distribution, and the existence of the infilled joints induces a nonlinear mechanical behavior in the specimen. In addition, the specimens exhibit three failure modes under uniaxial compression: splitting failure, step-path failure and planar failure. The specimens present two failure modes under biaxial compression: splitting failure and planar failure.

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

“…However, the influence of transverse joints was also not considered in their study. Han et al (2018) investigated the failure mechanism of intermittent jointed rock masses subjected to biaxial compression by physical tests. However, they did not consider the continuous joints perpendicular to the intermittent joints.…”

Study on the Influence of the Joint Angle between Blast Holes on Explosion Crack Propagation and Stress Variation

“…Among them, joint cracks are the most widely distributed structural plane in rock masses [1]. The existence of joints in a rock mass seriously affects the mechanical properties of the rock mass, the smooth blasting forming effect, and the stability of the surrounding rock after blasting, among which the joint angle has the greatest influence on the smooth blasting forming effect of roadways [2,3]. Therefore, this paper takes the joint angle as the starting point to study the expansion of explosive cracks in rock masses under different joint angles and the stress variation of rock mass elements, and it summarizes the specific influence of different joint angles on the smooth blasting of roadways to provide guidance for practical engineering.…”

Experimental Investigation on Failure Modes and Mechanical Properties of Rock‐Like Specimens with a Grout‐Infilled Flaw under Triaxial Compression

“…Lu et al [16] conducted direct shear tests on sandstone samples grouted with cement to study the influence of the filling ratio on the shear strength and failure behavior. Han et al [17] carried out uniaxial and biaxial compressive tests on the rock-like specimens with grout-infilled flaws having different flaw dip angles and found that the failure modes for uniaxial compressive tests are different to those for biaxial compressive tests. Experimental and numerical methods were followed by Chang et al [18] to investigate the strength and crack behavior of rock samples with a filled fissure under uniaxial compression, and their results show that, if the filling strength is lower than the critical value, secondary cracks disappear as the filling strength increases; however, if the filling strength is larger than the critical value, cracking behaviors are not affected by the filled flaw.…”