Journal Published Online: 28 July 2023
Volume 51, Issue 6

Experimental and Analytical Study on Optimal Spacing for Hard-Rock Breaking under Double-Indenter Impact

CODEN: JTEVAB

Abstract

Rock breaking by double hydraulic hammers has a wide application prospect in hard-rock roadway excavation because of its environmental protection and strong rock-breaking ability, but the optimal spacing under double-indenter synchronous impact is not clear. Based on the rock-breaking experimental system under double-indenter synchronous impact established by combining a detachable double-indenter device and Hopkinson pressure bar, the impact tests of three kinds of rocks are carried out, and a theoretical model of specific energy consumption is derived to determine the optimal spacing. The results show that when the indenter spacing is 28 mm, 42 mm, and 14 mm, respectively—that is, when the cross section of the fragmentation crater is in the shape of a “peanut” with a fine middle and two large ends—the concrete, limestone, and sandstone specimens reach the minimum specific energy consumption, which is reduced by 22.55 %, 30.60 %, and 11.85 %, respectively, compared with single-indenter impact. The theoretical model, which explains and verifies the experimental phenomena and results well, can be divided into four zones, and the optimal spacing is in Zone III. The research can be helpful for actual hard-rock tunneling under double hydraulic hammers.

Author Information

Yue, Zhongwen
School of Mechanics and Civil Engineering, China University of Mining and Technology, Beijing, China
Wang, Peng
School of Mechanics and Civil Engineering, China University of Mining and Technology, Beijing, China
Li, Akang
School of Mechanics and Civil Engineering, China University of Mining and Technology, Beijing, China
Ren, Meng
School of Mechanics and Civil Engineering, China University of Mining and Technology, Beijing, China
Gao, Dan
School of Mechanics and Civil Engineering, China University of Mining and Technology, Beijing, China
Bu, Wenyang
School of Mechanics and Civil Engineering, China University of Mining and Technology, Beijing, China
Han, Hui
School of Mechanics and Civil Engineering, China University of Mining and Technology, Beijing, China
Pages: 24
Price: $25.00
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Stock #: JTE20230098
ISSN: 0090-3973
DOI: 10.1520/JTE20230098