Theoretical and Experimental Study on Damage Properties of Surrounding Rock under High‐Frequency Constant Impact Load

Abstract

This paper aims to investigate the mechanics and damage properties of granite by drilling a center hole in Φ50 × 100 mm standard granite specimens under high-frequency constant impact load and then applying them to the uniaxial compression experiment through the INSTRON 1346 universal material testing machine. According to the experimental results, under constant impact load, as the center hole diameter increases, the peak stress of the rock specimen increases accordingly and the effective elastic modulus of the rock specimen decreases first and then increases gradually. In this study, by theoretical analysis of the surrounding rock damage caused under high-frequency impact load, a statistical damage constitutive model that has taken surrounding rock damage into consideration is established on the basis of the Weibull distribution. Meanwhile, the experimental curve is obtained to analyze the damage and damage radius of surrounding rock under high-frequency impact load. The results show that the surrounding rock damage and damage ratio (the ratio of damage radius to center hole radius) of rock decrease with the increase of the center hole diameter. This model that can effectively describe the damage laws of surrounding rock under impact load serves as a guide for the design and development of composite rock-drilling tools.

Damage evolution and fracture behavior of different materials specimens containing a central hole subjected to local loading

“…There are several studies on influence of preexisting holes on the properties of the rock specimen including stimulative and inhibitory effects. The effective elastic modulus firstly decreased and then gradually increased with the size of hole in the specimen increasing, and a statistical damage constitutive model can be established 13 . The failure mode, location and strength of pores of different shapes were mainly affected by lateral pressure 14 , with the increase of lateral pressure coefficient, the failure was further intensified, which mostly occurred in the roof and floor of the central pore.…”

Theoretical and Experimental Study of the Effects of Impact Drilling Parameters on the Properties of Surrounding Rock Damage

“…Many wide-ranging studies in China and globally have been conducted on these issues, leading to the rapid development of a focus on rock-damage mechanics in geotechnical engineering [1,2]. e rock-breaking method of drilling and blasting is widely used in rock excavation around the world because of its low cost, low blasting energy, and ready acceptance by blasting engineers [3][4][5]. In this method, a high-frequency and high-velocity hammer imparts a force to the rock upon impact by generating a stress wave sufficient to cause the rock to fracture or be damaged.…”