Time interval of short delay ignition is an important factor to affect theefficiency of blasting cuts. The motion process of rock pieces in the cut cavity is analyzed, amechanical model to calculate the delay time of ...Time interval of short delay ignition is an important factor to affect theefficiency of blasting cuts. The motion process of rock pieces in the cut cavity is analyzed, amechanical model to calculate the delay time of parallel hole cuts is presented for tunnel blasting,and a theoretical method to determine the volume ratio (the clearage rate) of the rock pieceswithin the cut cavity at different moments is proposed for the blasting cut with an empty hole.Numerical analysis results show that the optimal delay interval is proportional to the boreholedepth. The suggested results are of practical value to the optimal design of the delay interval inmillisecond blasting related to the parallel hole cuts with an empty hole.展开更多
The cavity formation and propagation process of stress wave from parallel hole cut blasting was simulated with ANSYS/LS-DYNA 3D nonlinear dynamic finite element software. The distribution of element plastic strain, no...The cavity formation and propagation process of stress wave from parallel hole cut blasting was simulated with ANSYS/LS-DYNA 3D nonlinear dynamic finite element software. The distribution of element plastic strain, node velocity, node time-acceleration history and the blasting cartridge volume ratio during the process were analyzed. It was found that the detonation of charged holes would cause the interaction of stress wave with the wall of uncharged holes. Initial rock cracking and displacement to neighboring uncharged holes become the main mechanism of cavity formation in early stage.2008 University of Science and Technology Beijing. All rights reserved.展开更多
Reducing the blasting vibration is important for blasting excavation in subway tunnel construction.Taking the 3rd bid section of Line 3 of Qingdao subway project as an example,the distance between tunnel vault and gro...Reducing the blasting vibration is important for blasting excavation in subway tunnel construction.Taking the 3rd bid section of Line 3 of Qingdao subway project as an example,the distance between tunnel vault and ground is 5 ~ 8 m.In order to insure the safety of the upper buildings,technologies of parallel cut with large diameter empty hole,one-time initiation and delay by parts,and multiple shallow holes were adopted in the project.The results showed that the maximum value of vertical vibration was limited in the criterion allowance,and the upper buildings were not damaged.Besides,problems were solved that the number of nonel detonator was difficult to meet the requirements of excavating a large cross-section tunnel by blasting,multiple cross-section could’t be initiated simultaneously,and construction efficiency was low,which ensure the construction safety and schedule.展开更多
建立了大直径中空直孔掏槽爆破的力学模型,采用FEM-SPH(Finite Element Method-Smooth Particle Hydrodynamics)耦合算法对破岩过程进行了数值模拟。结果表明:该数值模拟方法能够直观展示大直径中空直孔掏槽爆破破岩全过程,爆破破岩过...建立了大直径中空直孔掏槽爆破的力学模型,采用FEM-SPH(Finite Element Method-Smooth Particle Hydrodynamics)耦合算法对破岩过程进行了数值模拟。结果表明:该数值模拟方法能够直观展示大直径中空直孔掏槽爆破破岩全过程,爆破破岩过程分为端部爆破漏斗形成和槽腔岩体抛掷两个阶段;理论计算所得端部爆破漏斗边界与数值模拟所得漏斗边界基本一致,而理论计算所得最终槽腔边界与数值模拟所得槽腔边界存在差异,数值模拟所得最终槽腔边界呈倒立钟形,更符合最终槽腔边界的实际观测情况。研究结果为合理确定大直径中空直孔掏槽爆破参数提供了理论依据。展开更多
基金This work was financially supported by the National Natural Science Foundation of China (No. 59974019)
文摘Time interval of short delay ignition is an important factor to affect theefficiency of blasting cuts. The motion process of rock pieces in the cut cavity is analyzed, amechanical model to calculate the delay time of parallel hole cuts is presented for tunnel blasting,and a theoretical method to determine the volume ratio (the clearage rate) of the rock pieceswithin the cut cavity at different moments is proposed for the blasting cut with an empty hole.Numerical analysis results show that the optimal delay interval is proportional to the boreholedepth. The suggested results are of practical value to the optimal design of the delay interval inmillisecond blasting related to the parallel hole cuts with an empty hole.
文摘The cavity formation and propagation process of stress wave from parallel hole cut blasting was simulated with ANSYS/LS-DYNA 3D nonlinear dynamic finite element software. The distribution of element plastic strain, node velocity, node time-acceleration history and the blasting cartridge volume ratio during the process were analyzed. It was found that the detonation of charged holes would cause the interaction of stress wave with the wall of uncharged holes. Initial rock cracking and displacement to neighboring uncharged holes become the main mechanism of cavity formation in early stage.2008 University of Science and Technology Beijing. All rights reserved.
文摘Reducing the blasting vibration is important for blasting excavation in subway tunnel construction.Taking the 3rd bid section of Line 3 of Qingdao subway project as an example,the distance between tunnel vault and ground is 5 ~ 8 m.In order to insure the safety of the upper buildings,technologies of parallel cut with large diameter empty hole,one-time initiation and delay by parts,and multiple shallow holes were adopted in the project.The results showed that the maximum value of vertical vibration was limited in the criterion allowance,and the upper buildings were not damaged.Besides,problems were solved that the number of nonel detonator was difficult to meet the requirements of excavating a large cross-section tunnel by blasting,multiple cross-section could’t be initiated simultaneously,and construction efficiency was low,which ensure the construction safety and schedule.
文摘建立了大直径中空直孔掏槽爆破的力学模型,采用FEM-SPH(Finite Element Method-Smooth Particle Hydrodynamics)耦合算法对破岩过程进行了数值模拟。结果表明:该数值模拟方法能够直观展示大直径中空直孔掏槽爆破破岩全过程,爆破破岩过程分为端部爆破漏斗形成和槽腔岩体抛掷两个阶段;理论计算所得端部爆破漏斗边界与数值模拟所得漏斗边界基本一致,而理论计算所得最终槽腔边界与数值模拟所得槽腔边界存在差异,数值模拟所得最终槽腔边界呈倒立钟形,更符合最终槽腔边界的实际观测情况。研究结果为合理确定大直径中空直孔掏槽爆破参数提供了理论依据。