A rapid method for measuring the rock brittleness index: Rapid characterization of rock brittleness based on LIBS technology

IF 6.7 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Tunnelling and Underground Space Technology Pub Date : 2024-10-16 DOI:10.1016/j.tust.2024.106143

Qinghe Zhang , Weiguo Li , Liang Yuan , Chao Liang , Honggui Pan

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引用次数: 0

Abstract

The brittle index is a crucial indicator in the assessment of rockbursts. The mineral brittle index (MBI) is widely utilized due to its simplicity and accessibility. However, the lengthy and inefficient mineral composition testing cycle presents a significant challenge. A novel approach using laser-induced breakdown spectroscopy (LIBS) to rapidly convert spectral elements into minerals and measure the rock brittleness index was introduced in this paper. The laser spectra of metamorphic sandstone and granite were measured by LIBS, and some rock elements were tested by X-ray fluorescence (XRF) to construct a spectral-elemental model. Furthermore, the mineral composition of the rocks was determined by X-ray diffraction (XRD). Eight major elements, Si, Al, K, Ca, Na, Fe, Mg, and Ti, were selected as independent variables. Element-mineral correlation analysis was performed using centered log-ratio transformation (CLR) processing. A random forest regression (RF-R) element-mineral transformation model was established for rapid conversion of spectral-element-mineral brittle index. Finally, mechanical testing of rock embrittlement in the DJ Tunnel was conducted to verify the efficacy of MBI in characterizing rock embrittlement in the DJ Tunnel. The results demonstrate that predicted values of mineral compositions are in good agreement with experimental values and that predicted values of brittleness indices are also in good agreement with experimental values. The rapid and effective application of LIBS in determining rock mineral composition and rock brittleness index has been realised, which is of great significance for further realising the rapid assessment of rock brittleness and rockburst prediction at engineering sites.

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岩石脆性指数的快速测量方法：基于 LIBS 技术的岩石脆性快速表征方法

脆性指数是评估岩爆的一个重要指标。矿物脆性指数（MBI）因其简单易行而被广泛使用。然而，矿物成分测试周期长、效率低，是一项重大挑战。本文介绍了一种利用激光诱导击穿光谱（LIBS）快速将光谱元素转换为矿物并测量岩石脆性指数的新方法。利用激光诱导击穿光谱仪测量了变质砂岩和花岗岩的激光光谱，并通过 X 射线荧光（XRF）检测了部分岩石元素，从而构建了光谱元素模型。此外，还利用 X 射线衍射（XRD）测定了岩石的矿物成分。选取了 Si、Al、K、Ca、Na、Fe、Mg 和 Ti 八种主要元素作为自变量。采用居中对数比率变换（CLR）处理法进行元素-矿物相关性分析。建立了随机森林回归（RF-R）元素-矿物转换模型，用于快速转换光谱-元素-矿物脆性指数。最后，对 DJ 隧道中的岩石脆性进行了机械测试，以验证 MBI 在表征 DJ 隧道中岩石脆性方面的功效。结果表明，矿物成分的预测值与实验值十分吻合，脆性指数的预测值与实验值也十分吻合。在确定岩石矿物成分和岩石脆性指数方面实现了 LIBS 的快速有效应用，这对进一步实现工程现场岩石脆性的快速评估和岩爆预测具有重要意义。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Tunnelling and Underground Space Technology 工程技术-工程：土木

CiteScore

11.90

自引率

18.80%

发文量

454

审稿时长

10.8 months

期刊介绍： Tunnelling and Underground Space Technology is an international journal which publishes authoritative articles encompassing the development of innovative uses of underground space and the results of high quality research into improved, more cost-effective techniques for the planning, geo-investigation, design, construction, operation and maintenance of underground and earth-sheltered structures. The journal provides an effective vehicle for the improved worldwide exchange of information on developments in underground technology - and the experience gained from its use - and is strongly committed to publishing papers on the interdisciplinary aspects of creating, planning, and regulating underground space.