An Experimental Study on Mechanical Behavior of Parallel Joint Specimens under Compression Shear

Abstract

In order to investigate the influence of the joint on the failure mode, peak shear strength, and shear stress-strain curve of rock mass, the compression shear test loading on the parallel jointed specimens was carried out, and the acoustic emission system was used to monitor the loading process. e joint spacing and joint overlap were varied to alter the relative positions of parallel joints in geometry. Under compression-shear loading, the failure mode of the joint specimen can be classified into four types: coplanar shear failure, shear failure along the joint plane, shear failure along the shear stress plane, and similar integrity shear failure. e joint dip angle has a decisive effect on the failure mode of the specimen. e joint overlap affects the crack development of the specimen but does not change the failure mode of the specimen. e joint spacing can change the failure mode of the specimen. e shear strength of the specimen firstly increases and then decreases with the increase of the dip angle and reaches the maximum at 45°. e shear strength decreases with the increase of the joint overlap and increases with the increase of the joint spacing. e shear stress-displacement curves of different joint inclination samples have differences which mainly reflect in the postrupture stage. From monitoring results of the AE system, the variation regular of the AE count corresponds to the failure mode, and the peak value of the AE count decreases with the increase of joint overlap and increases with the increase of joint spacing.

Experimental study on fracture characteristics of rock-like material with prefabricated cracks under compression shear

“…They understood the damage pattern of the specimens and the factors influencing the failure mode and peak strength of the specimens. Wang et al 16 carried out compression shear tests on parallel joint specimens in order to investigate the effect of joints on the damage mode, peak shear strength and shear stress–strain curve of the rock mass. They understood the effect of different joints on the fracture mode.…”