Work

Study on the most optimistic hole spacing for double-hole blasting under high in-situ stresses

Year: 2025

Type: article

Abstract: As a typical contour blasting technique，presplitting blasting is widely used in rock engineering excavation for foundation pits，highway slopes，open-pit and underground mines. Due to the influence of in-situ stress，deep presplitting blasting requires small-diameter fully coupled charges and closely spaced holes，which affects construction timelines and significantly increases costs. This study aims to investigate the correlation between optimal hole spacing and radial decoupling coefficients under high in-situ stress through theoretical derivation and numerical analysis. A double-hole presplitting blasting model is established using linear elastic theory，incorporating the stress wave superposition effect. This model determines the optimal relationship curves for hole spacing and radial decoupling coefficients under different high in-situ stresses. Using the self-developed OpenFDEM software，simulations are conducted to assess the expansion of the blasting fragmentation zone and fracture zone under various stress conditions and radial decoupling charges. The results indicate that the stress wave superposition effect promotes crack penetration. At low stress conditions，a lower decoupling coefficient significantly enhances crack extension. However，it also increases the density and extent of fracture branching. This enlarges the damage zone and hinders the formation of pre-splitting cracks. As in-situ stress increases，the influence of the stress wave superposition effect diminishes. This further affects the pre-splitting cracks formation in double-hole blasting. This paper proposes optimal hole spacing values that fully consider the interaction between high in-situ stress and stress wave superposition effects，providing important references for enhancing pre-splitting cracks formation in double-hole blasting.

Source: Chinese journal of rock mechanics and engineering

DOI: 10.3724/1000-6915.jrme.2024.0545

Authors: Qian LI, Haibo LI, Shuaiyang FU, Minghe JU, Xiaofeng LI

Institutions: Chinese Academy of Sciences, Institute of Rock and Soil Mechanics, State Key Laboratory of Geomechanics and Geotechnical Engineering

Language: English

Topic: Blasting Impact and Analysis

Subfield: Building and Construction

Field: Engineering

Domain: Physical Sciences

Open Access status: bronze

Funder: National Natural Science Foundation of China

Award: G5061336959