{"title":"A new early warning method for rockbursts and compound rockburst–collapse hazards in deeply-buried tunnels based on energy density","authors":"Zhihao Kuang , Shili Qiu , Shaojun Li , Yaxun Xiao , Guangliang Feng , Yong Huang , Shuaipeng Chang","doi":"10.1016/j.tust.2025.106828","DOIUrl":null,"url":null,"abstract":"<div><div>Rockbursts and compound rockburst–collapse hazards frequently occur when deeply-buried tunnels are constructed in regions subject to significant geological variation and intense tectonic activity. These hazards are characterized by their sudden and highly destructive nature, thus posing a major threat to construction safety and engineering stability. The evolution of such hazards is usually accompanied by microseismic (MS) events that alternate between two different phases: long, quiet periods and short periods of eruption. Accurately identifying the transition interval between these phases (thus allowing hazard warnings to be issued in a timely manner) has thus become a critical issue that needs to be solved in current hazard warning systems. To address this issue, this paper proposes a new warning method based on the spatial evolution patterns of the MS events that occur during the development of rockbursts and compound rockburst–collapse hazards. We call it the ‘logarithmic energy density’ (logED) method as the indicator used is the logarithm of the energy density of the effective MS events released within the warning unit employed. It can be calculated using the WOA-DBSCAN clustering method and Quickhull3D algorithm. In this paper, five hazard cases are taken from a tunnel engineering project in southwestern China to use as study objects. The evolution characteristics of logED associated with these hazards as they evolve were systematically analyzed. The results show that logED can effectively capture the subtle and critical spatial distribution changes of the MS events in the precursor phase of the hazards and accurately identify the transition interval between long, quiet periods and short, eruption periods during the evolution phase. Compared with traditional hazard warning methods based on the logarithm of the MS energy released, logED has significant advantages in terms of improved prediction accuracy and sensitivity. Furthermore, the hazard warning method proposed in this paper is multi-parameter. That is, it combines an analysis of the changes in logarithmic MS energy released and logED, which allows it to precisely capture the subtle spatial distribution changes of the MS events and identify key transitional moments during the hazard evolution period. This effectively eliminates many misjudgments that often occur using single-parameter analysis methods. The proposed method provides new data dimensions and analytical tools for hazard prediction, significantly improves the scientificity and accuracy of the hazard warnings, and offers important theoretical support and practical guidance for the improvement and optimization of hazard warning systems.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"164 ","pages":"Article 106828"},"PeriodicalIF":7.4000,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Tunnelling and Underground Space Technology","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0886779825004663","RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CONSTRUCTION & BUILDING TECHNOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Rockbursts and compound rockburst–collapse hazards frequently occur when deeply-buried tunnels are constructed in regions subject to significant geological variation and intense tectonic activity. These hazards are characterized by their sudden and highly destructive nature, thus posing a major threat to construction safety and engineering stability. The evolution of such hazards is usually accompanied by microseismic (MS) events that alternate between two different phases: long, quiet periods and short periods of eruption. Accurately identifying the transition interval between these phases (thus allowing hazard warnings to be issued in a timely manner) has thus become a critical issue that needs to be solved in current hazard warning systems. To address this issue, this paper proposes a new warning method based on the spatial evolution patterns of the MS events that occur during the development of rockbursts and compound rockburst–collapse hazards. We call it the ‘logarithmic energy density’ (logED) method as the indicator used is the logarithm of the energy density of the effective MS events released within the warning unit employed. It can be calculated using the WOA-DBSCAN clustering method and Quickhull3D algorithm. In this paper, five hazard cases are taken from a tunnel engineering project in southwestern China to use as study objects. The evolution characteristics of logED associated with these hazards as they evolve were systematically analyzed. The results show that logED can effectively capture the subtle and critical spatial distribution changes of the MS events in the precursor phase of the hazards and accurately identify the transition interval between long, quiet periods and short, eruption periods during the evolution phase. Compared with traditional hazard warning methods based on the logarithm of the MS energy released, logED has significant advantages in terms of improved prediction accuracy and sensitivity. Furthermore, the hazard warning method proposed in this paper is multi-parameter. That is, it combines an analysis of the changes in logarithmic MS energy released and logED, which allows it to precisely capture the subtle spatial distribution changes of the MS events and identify key transitional moments during the hazard evolution period. This effectively eliminates many misjudgments that often occur using single-parameter analysis methods. The proposed method provides new data dimensions and analytical tools for hazard prediction, significantly improves the scientificity and accuracy of the hazard warnings, and offers important theoretical support and practical guidance for the improvement and optimization of hazard warning systems.
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.