| 常素玲,王在泉*,丛宇,陈凡秀.冲击荷载下直墙拱隧道破坏机制研究[J].实验力学,2025,40(1):101~114 |
| 冲击荷载下直墙拱隧道破坏机制研究 |
| The research of failure mechanism of straight wall arch cavern under impact load |
| 投稿时间：2024-07-03 修订日期：2024-07-20 |
| DOI：10.7520/1001-4888-23-136 |
| 中文关键词: 冲击荷载 直墙拱 细观力学 颗粒流数值模拟 |
| 英文关键词:impact load straight arch wall cavern meso-mechanical behavior particle flow simulation |
| 基金项目:国家自然科学基金项目(52179104); 山东省自然科学基金项目(ZR2019BEE051，ZR2020ME099，ZR2020MD111)；泰山学者工程专项经费(tsqn202211180) |
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| 中文摘要: |
| 为探明冲击荷载作用下隧道的破坏机制，本文基于大尺寸直墙拱试样摆锤冲击试验，采用颗粒流数值软件(PFC3D)模拟直墙拱隧道冲击破坏过程，分析隧道周边裂纹、应力、速度时空演化细观力学行为，结果表明：(1)在频率为250 Hz的冲击荷载作用下，裂纹发育经历萌生期、激增期、缓增期3个阶段。裂纹数目增长率最快超过每秒105个。裂纹类型是以张拉为主的拉剪复合裂纹。(2)起裂应力大小受断面形状影响，不同位置应力响应规律不同，拱脚位置首先到达起裂应力，其次是拱肩。(3)裂纹发育阶段，直墙拱周围速度矢量历经“中心对称→上下对称→左右对称”变化过程，速度矢量大小以直墙拱为中心从“近大远小”向“近小远大”转变，裂纹出现在速度矢量变化较大处。本文研究成果可为深入理解隧道在冲击荷载作用下的破坏过程和机理提供参考。 |
| 英文摘要: |
| Based on the pendulum impact experiment of the straight wall arch cavern, PFC3D was used to simulate the failure process and analyze the meso-mechanical behavior including stress, crack, velocity evolution. The research results indicate: (1) Under the impact load with a frequency of 250 Hz, the development of cracks goes through three stages: initiation period, rapid growth period, and slow growth period. The growth rate of the number of cracks can reach as high as 105 per second. The type of cracks is primarily tensile-shear mixed cracks dominated by tension. (2) The magnitude of the crack initiation stress is influenced by the shape of the cross-section. There are different stress response patterns at different locations, with the corner reaching the crack initiation stress firstly, followed by the arch shoulder. (3) During the crack development stage, the velocity vectors around the straight wall arch undergo a spatial distribution change from “center symmetry → upper-lower symmetry → left-right symmetry”, and the magnitude of the velocity vectors changes from “near-large and far-small”to “near-small and far-large” with the straight wall arch as the center. Cracks initate in areas where the magnitude of the velocity vectors changes significantly. The research findings of this paper can provide a reference for a deeper understanding of the failure process and mechanism of tunnels under the impact loads. |
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