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隧道建设(中英文) ›› 2023, Vol. 43 ›› Issue (8): 1360-1368.DOI: 10.3973/j.issn.2096-4498.2023.08.010

• 研究与探索 • 上一篇    下一篇

横置椭圆形砂岩隧洞裂纹扩展特征与破坏征兆研究

朝文文1, 徐培元2, 张黎明2, *, 王建新3, 张素磊2, 王在泉2, 丛宇2   

  1. (1. 青岛理工大学理学院, 山东 青岛 266033 2. 青岛理工大学土木工程学院,山东 青岛 266033; 3. 应急管理部国家自然灾害防治研究院, 北京 100085)

  • 出版日期:2023-08-20 发布日期:2023-09-11
  • 作者简介:朝文文(1999—),女,河南信阳人,青岛理工大学力学专业在读硕士,研究方向为岩石力学与地下工程。 Email: chaoww99@163.com。 *通信作者: 张黎明,Email: dryad_274@163.com。

Crack Propagation Characteristics and Failure Symptom of Transverse Elliptical Sandstone Tunnel

CHAO Wenwen1, XU Peiyuan2, ZHANG Liming2, *, WANG Jianxin3, ZHANG Sulei2,WANG Zaiquan2, CONG Yu2   

  1. (1. School of Science, Qingdao University of Technology, Qingdao 266033, Shandong, China;2. School of Civil Engineering, Qingdao University of Technology, Qingdao 266033, Shandong, China;3. National Institute of Natural Hazards, Beijing 100085, China)

  • Online:2023-08-20 Published:2023-09-11

摘要: 为研究椭圆形隧洞破坏过程及演化预警问题,开展真实砂岩横置椭圆形隧洞双轴压缩试验,结合声发射、DIC实时采集系统分析横置椭圆形隧洞裂纹渐进扩展过程特征。结果表明: 1)隧洞首先在拱顶和拱底出现张拉裂纹,随后在洞口两侧出现剪切裂纹和远场裂纹,在洞口右侧壁形成V形槽,最终远场裂纹与V形槽连通导致隧洞发生脆性破坏; 2)隧洞表面应变集中区先于裂纹出现,能够预判裂纹出现的位置; 3)裂纹稳定扩展阶段,分形维数逐渐增大,剪切裂纹起裂时分形维数增速率加快,峰值荷载前分形维数出现突增; 4)隧洞破坏前会出现声发射平静期、b值突降、熵值突增、应变场方差突增、裂纹分形维数突增等预警信息,不同物理场监测数据的预警时间不同步,预警荷载为峰值荷载的87%~97%,b值突降出现最早,应变场方差突增出现最晚。

关键词: 横置椭圆形隧洞, 裂纹扩展, 声发射, DIC, 分形维数, 破坏预警

Abstract: A biaxial compression test is conducted on a real sandstone transverse elliptical tunnel; moreover, the characteristics of the progressive crack propagation process of the transverse elliptical tunnel are analyzed with acoustic emission and a digital image correlation realtime acquisition system to investigate the failure process and evolution warning of the elliptical tunnel. The results show the following: (1) Tensile cracks first appear in the tunnels crown and bottom; subsequently, shear and farfield cracks appear on both sides of the tunnel. Furthermore, a Vshaped groove is formed on the right sidewall of the tunnel, and the farfield cracks extend to the Vshaped groove, leading to the brittle failure of the tunnel. (2) The strain concentration area on the tunnel surface appears before the crack, and the cracks location can be predicted. (3) The fractal dimension gradually increases from zero in the stable crack propagation stage. When the tunnel shear crack starts, the growth rate of the fractal dimension accelerates. The fractal dimension shows a sudden increase before reaching the peak tunnel load. (4) At a quiet period, the sudden drop of the WTBXbWT5《TNR》〗 value, a sudden increase in the entropy value, a sudden increase in strain field variance, and a sudden increase in the crack fractal dimension can be used as early warning information before tunnel failure. The early warning time of different physical fields monitoring data is not synchronized, and the early warning load is 87% to 97% of the peak load. The sudden drop of the WTBXbWT5《TNR》〗 value is the earliest and the sudden strain field variance increase is the latest.

Key words: transverse elliptical tunnel, crack propagation, acoustic emission, digital image correlation, fractal dimension, damage warning