Abstract

This study prepares rock-like intact specimens and specimens that contain singly, smoothly planar joint with various joint angles for the SHBP test. A buffer pad between striker bar and incident bar of a SHPB apparatus is utilized to absorb part of shock energy, and thus generates loading rates of 20.2–4122.2 GPa/s to investigate temperature variations and associated failure patterns of specimens. The influence of loading rate and associated applying angles on temperature variation of specimens are examined accordingly. Experimental results demonstrate that the failure pattern of each specimen can be classified as (A) integrated with or without tiny flake-off, (B) slide failure, (C) fracture failure, or (D) crushing failure, depending on loading rate and whether the specimen contains a smoothly planar joint that allow appropriate sliding between two blocks of the specimen. After SHPB test, temperature variation of a specimen increases with loading rate and the relationship is positive correlation. The included angle between the smoothly planar joint and loading direction affects the ranges of loading rate that yield different failure patterns, and thus influences temperature variation of specimens.

1. Introduction

The rock material has be failure or deformation owing to external force and the phenomenon belong to energy transform into deformation has been frequently reported (Zhou et al., 2010; Zhou et al., 2012; Liu and Xu, 2013), but research regarding the thermal energy change from material internal part has seldom been considered. Underground engineering and blasting are demand to expel the rock mass rapidly. Besides alter stress value, loading rate cause different degree effect (Zhao et al., 2014; Zhang and Zhao, 2014). Temperature variation and the failure pattern of rock mass are significantly influence the underground engineering_ characteristics (Huang and Xia, 2015), especially discontinuities in a rock mass not only affecting the strength and deformation but also affecting the transfer of energy in rock mass (Liu et al., 2015). Few studies have focused on the effects of loading rate and angle of application on the engineering characteristics in rock mass, and different types of energy conversion are also seldom been knew. Lacking of the information is unfavorable for application on the underground space exploitation and underground resources.

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