珊瑚礁灰岩中爆炸波传播试验研究

Experimental study on blast wave propagation in coral reef limestone

摘要

【目的】为了解决珊瑚礁灰岩因岩芯尺寸小且非均质性强，导致大比尺爆炸冲击试验难以开展，以及爆炸波传播规律难以获取的问题，【方法】基于爆炸波精细电磁量测法的小尺度化爆模拟技术，通过中心起爆微型炸药球与圆环形电磁粒子速度计的组合设计，实现了礁灰岩中比例爆距为$20 \sim 80 \mathrm{~m} / \mathrm{kt}^{\frac{1}{3}}$范围内爆炸波粒子速度时程曲线的精准测量。【结果】结果表明：礁灰岩中爆炸波从强间断冲击波的形式逐渐退化为连续的压缩波，持续时间逐渐增加，粒子速度峰值逐渐减小；试验范围内，礁灰岩中爆炸波的应力峰值与粒子比位移峰值衰减指数分别为1.89和1.39;礁灰岩爆炸成腔明显，但因天然存在的孔隙和裂隙体系对爆炸波具有较强的削弱能力，抑制了爆生裂隙的发育与扩展，爆后礁灰岩以孔隙的变形与压实及天然裂隙的扩展为主。【结论】揭示了礁灰岩中爆炸破坏效应和应力与比位移峰值传播衰减规律，提出了爆炸波传播衰减计算公式，为礁灰岩爆炸冲击效应分析提供试验支撑。

Abstract

[Objective] The aim is to address the difficulties in conducting large-scale explosion impact tests on coral reef limestone due to the small core size and strong heterogeneity, as well as the challenges in obtaining the propagation patterns of blast waves. [Methods] Based on the small-scale explosion simulation technology using the fine electromagnetic measurement method for blast waves, a combined design of the center-detonated miniature spherical explosive and the circular electromagnetic particle velocimeter was adopted to precisely measure the time-history curves of blast wave particle velocity in reef limestone at scaled distances of $20 \sim 80 \mathrm{~m} / \mathrm{kt}^{\frac{1}{3}}$ The result showed that the blast waves in reef limestone progressively degraded from strong intermittent shock waves into continuous compression waves, with gradually increasing duration and decreasing peak particle velocity. Within the test range, the attenuation indices of the peak stress and peak particle specific displacement of the blast waves in reef limestone were 1.89 and 1.39, respectively. Explosion-induced cavity formation in the reef limestone was obvious, but the natural pore and fracture systems significantly attenuated blast waves, inhibiting the development and propagation of explosion-induced fractures. After the explosion, the reef limestone was mainly characterized by deformation and compaction of the pores and the extension of natural fractures. [Conclusion] The research findings reveal the explosion-induced damage effects and the propagation attenuation patterns of peak stress and peak specific displacement in reef limestone, and propose a calculation formula for blast wave attenuation, providing experimental support for the analysis of the explosion impact effects in reef limestone.

关键词

礁灰岩 / 电磁法 / 微型炸药球 / 爆炸波 / 衰减系数 / 破坏效应 / 影响因素 / 爆炸冲击效应

Key words

reef limestone / electromagnetic method / miniature spherical explosive / blast wave / attenuation coefficient / damage effect / influencing factors / explosion impact effects

基金资助

国家自然科学基金优秀青年科学基金项目(52222110)

2023年度国家重点研发计划