Journal Article

Experimental Study and Mechanism Analysis on the Effects of Biaxial In-Situ Stress on Hard Rock Blasting

Ku, Taeseo, Hao, Qiqi, Zhang, Fengpeng, Yan, Guangliang, Peng, Jianyu

2023

Overview

Drill and blast method is widely applied in deep rock engineering, and the in-situ stress poses a great challenge to blasting excavation. The failure mechanism of rock under coupled dynamic and static loads and the effect of in-situ stress on blasting effects are major concerns when dealing with deep rock blasting excavation. In this study, lab-scale crater blasting experiments on sandstone specimens under various equal biaxial compressive stresses were conducted to investigate the effects of in-situ stress on blasting effects and the mechanism of in-situ stress affecting rock blasting. The initiation and propagation of crack network, morphological characteristics of blasting crater, and distribution characteristics of blasting fragments under biaxial in-situ stress were studied. Besides, the quantitative relationships between biaxial in-situ stress and blasting crater parameters (diameter, area, and volume) were analyzed. The experimental results show that the biaxial static stress inhibits the formation of radial cracks and promotes the formation of circumferential cracks, resulting in the time delay of initial crack formation and the change of initial crack type from radial crack to circumferential crack. With increasing biaxial static stress, the diameter, area and volume of blasting crater, and the size and quantity of blasting fragments gradually increase. Meanwhile, blasting craters are all circular under the various biaxial static stresses. Biaxial static stress has significant influences on the evolution of flaky failure zone, while the effect on the block failure zone and transition failure zone is relatively small. Finally, the mechanisms of the effect of biaxial in-situ stress on the initiation and propagation of blast-generated cracks, blasting crater morphology, and blasting fragments’ distribution were analyzed theoretically.HighlightsCrater blasting experiments on hard stone under various biaxial in-situ stresses were conducted.The effects of static stress on cracks, blasting crater, and blasting fragments are investigated.Quantitative relationships between in-situ stress and blasting crater parameters are examined.Mechanism analysis of biaxial in-situ stress affecting blasting.

• Publisher: Springer Nature B.V
• Subject: Axial stress / Blasting / Compressive properties / Crack initiation / Crack propagation / Cracks / Craters / Diameters / Distribution / Excavation / Failure mechanisms / Fragments / Morphology / Parameters / Physical characteristics / Rocks / Sandstone / Sedimentary rocks / Static loads / Stress / Stress propagation