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Numerical Simulation on Selection of Optimal Delay Time for Precise Delay Blasting
Shock and Vibration ( IF 1.6 ) Pub Date : 2021-09-13 , DOI: 10.1155/2021/4593221
Jun Ma 1 , Xianglong Li 1, 2 , Jianguo Wang 1, 2 , Qiang Li 1 , Ting Zuo 1 , Xiao Wu 3 , Meng Hou 3
Affiliation  

In the traditional presplitting blasting, the presplit holes are generally uniformly initiated, which causes local damage to the retained rock mass while forming the damping ditch. In order to determine the optimal delay time of the precise delay initiation hole by hole, the finite element software ANSYS/LS-DYNA is used to build a blasting model of the concrete, which includes concrete, explosive, and air to simulate the crack forming process of the presplitting hole under various initiation modes. Four kinds of initiation modes for blasting, namely, simultaneous initiation with 0 ms, 9 ms, 12 ms, and 15 ms of delay between adjacent holes, are set up to determine the exact delay time of the best presplitting effect. The simulation results show that when the prehole detonates simultaneously, the inner hole crack penetrates the fastest, but the peak stress around the hole is up to 147.9 MPa. When interhole delayed initiation is used, although the time of interhole crack penetration is prolonged, the stress coupling is generated around the precrack and the maximum stress is obviously reduced. The maximum stress generated under the three delayed initiation conditions is only 76.8 MPa. Considering the requirement of damage control of surrounding rock mass and the rapid formation of precrack, 9 ms delay time is determined as the precise delay time of this test.

中文翻译:

精确延迟爆破最佳延迟时间选择的数值模拟

在传统的预裂爆破中,预裂孔一般是均匀起爆,在形成阻尼沟的同时,对保留的岩体造成局部破坏。为确定逐孔精确延迟起爆的最佳延迟时间,采用有限元软件ANSYS/LS-DYNA建立混凝土爆破模型,包括混凝土、炸药、空气模拟裂纹形成各种起爆方式下预裂孔的过程。设置了4种爆破起爆方式,即同时起爆,相邻孔间延迟0 ms、9 ms、12 ms和15 ms,以确定最佳预分裂效果的准确延迟时间。模拟结果表明,当预孔同时起爆时,内孔裂纹穿透速度最快,但孔周围的峰值应力高达147.9 MPa。采用孔间延迟起裂时,虽然延长了孔间裂纹穿透的时间,但在预裂纹周围产生了应力耦合,最大应力明显降低。三种延迟起爆条件下产生的最大应力仅为76.8 MPa。考虑到围岩破坏控制和预裂快速形成的要求,确定9 ms延迟时间作为本次试验的精确延迟时间。三种延迟起爆条件下产生的最大应力仅为76.8 MPa。考虑到围岩破坏控制和预裂快速形成的要求,确定9 ms延迟时间作为本次试验的精确延迟时间。三种延迟起爆条件下产生的最大应力仅为76.8 MPa。考虑到围岩破坏控制和预裂快速形成的要求,确定9 ms延迟时间作为本次试验的精确延迟时间。
更新日期:2021-09-13
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