ORIGINAL RESEARCH article
Front. Earth Sci.
Sec. Geohazards and Georisks
Volume 13 - 2025 | doi: 10.3389/feart.2025.1684101
This article is part of the Research TopicEvolution Mechanism and Prevention Technology of Karst Geological Engineering DisastersView all 19 articles
Experimental study on blasting with a short straight hole + wedge compound cut scheme in hard rock tunnels
Provisionally accepted- 1Wenshan Tianwen Expressway Investment and Development Co.,Ltd., Wenshan, China
- 2CCCC Rail Transit Branch,Beijing, beijing, China
- 3China Communications Construction Company Second Harbor Engineering Co., Ltd, Wuhan, China
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In drill-and-blast excavation for small- and medium-sized tunnels, the conventional wedge-cut blasting method is often constrained by the limited maneuvering space of construction equipment. This restriction can result in excessive inclination of wedge-cut holes relative to the tunnel face. Consequently, the rock in the cut zone is subjected to strong confinement, leading to reduced advance per round, low blasthole utilization efficiency, and an increased specific charge. In this study, theoretical analysis and formula derivation were conducted to evaluate the respective advantages and limitations of wedge cutting and straight-hole cutting. Based on these analyses, optimal layout parameters for straight holes were determined. A combined short straight-hole + wedge compound cut blasting scheme was subsequently proposed and tested in a hard rock tunnel. The field experiments yielded the following findings: When calculating the spacing between charge holes and relief holes, the influence of high strain rates on the rock’s tensile strength should be incorporated to ensure that theoretical parameters are both accurate and applicable. Compared with the original blasting scheme, the designed compound cut method increased the advance per round from 1.7–1.8 m to 2.0–2.1 m and improved blasthole utilization from 73.91%–78.26% to 86.96%–91.30%. The specific charge remained nearly unchanged, while detonator consumption decreased by approximately 0.4 detonators/m³, demonstrating clear economic benefits. The application of the short straight-hole + wedge compound cut technique also resulted in fewer remaining holes and finer rock fragmentation at the tunnel face, thereby enhancing the efficiency of muck removal and drilling operations in subsequent cycles. These results provide practical guidance for optimizing drill-and-blast design parameters and construction practices in small- and medium-scale hard rock tunneling projects.
Keywords: Water conveyance tunnel, Compound cut blasting, Blasting parameters, Circular tunnel, experiment
Received: 12 Aug 2025; Accepted: 30 Sep 2025.
Copyright: © 2025 TU, TANG, HE, PENG, YANG and XU. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Songlin PENG, ylshanwang86@163.com
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