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| 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：2023-07-03 修订日期：2023-07-20 |
| DOI： |
| 中文关键词: impact load straight arch wall cavern meso-mechanical behavior particle flow simulation |
| 英文关键词:冲击荷载 直墙拱 细观力学 PFC3D |
| 基金项目:国家自然科学基金(52179104) ; 山东省自然科学基金(ZR2019BEE051，ZR2020ME099，ZR2020MD111)， 泰山学者工程专项经费资助（tsqn202211180）。 |
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| 中文摘要: |
| 摘要 基于冲击荷载作用下直墙拱摆锤冲击室内试验，采用PFC3D模拟了其冲击破坏过程，分析了冲击荷载下直墙拱隧洞包含应力、裂纹、速度时空演化特征的细观力学行为，研究表明：（1）裂纹发育过程有典型的分阶段、分区域特征。冲击波源处裂纹发育持续约1.4ms，首先是远离冲击波表面拱脚裂纹先出现，同时裂纹萌生在拱肩处；扩展阶段裂纹增长率最快，达到1M个/s，持续时长0.3ms。（2）水平、竖直方向拉应力导致出现裂纹，裂纹均是以张拉为主的拉剪复合裂纹。不同位置起裂应力不同；应力响应时间有先后，拱脚首先达到较大值，其次是拱腰，最后是拱肩；不同位置水平、竖直方向合应力体现不同发展特征。（3）沿洞轴向振速最大，水平和竖直方向振速较小。速度分布围绕洞周随着时间呈现不同对称状态。速度云图细节特征与裂纹分布密切相关，裂纹出现在振速梯度较大处。 |
| 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 results show that: (1) The crack evolution can be divided into four stages with different features. The cracks emerge near shock wave within 1.4ms, and then initiate at the corner far from the shock wave. At 1.6ms the cracks initiate at the spandrel and last about 0.6ms. The crack growth rate is fastest during the propagation stage which reaches 106/s and lasts 0.3ms. The crack is mainly tensile.(2) Horizontal and vertical tensile stress lead to microcracks. The initiation stresses are different in different zones of the straight wall arch cavern. The response time of the corner is 1.45ms, follows by the sidewall at 1.5ms and the spandrel at 1.6ms. The composition stresses of horizontaland vertical directions show different trends.（3）The velocity along the is the largest while those in x and z direction are small. The velocity distributions around the cavern show different symmetries with time. The details of velocity distribution are closely related to the distribution of cracks, and the cracks appear at the zone with larger velocity gradient. |
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