独头隧道爆破冲击波传播特征与爆源因素影响分析

Analysis of propagation characteristics and influencing factors ofblasting shock waves in one-ended tunnel

为评估在隧道爆破冲击波作用下人员安全和建筑物毁伤问题,需要明晰施工隧道与交通隧道内爆破空气冲击波传播特征的区别。利用ANSYS/LS-DYNA软件对比分析独头与双向开口隧道内冲击波传播过程的差异性,研究爆源等效炸药当量、炸药多孔起爆及爆源位置等因素对爆破冲击波传播影响机制。结果表明:独头隧道内爆破冲击波传播经历三维球面波逐渐转换至一维平面波的3阶段变化模式,且独头隧道端部边界约束初始球面波几何扩散,经壁面反射叠加的超压增幅达20%;爆源炸药当量影响着波阵面变化,3阶段变化模式的波阵面转换位置与炸药当量呈幂函数负相关关系,随炸药当量提高而在更接近爆源位置转换;多炮孔起爆工况近场超压更大,而进入远场一维平面波传播区域,多炮孔起爆和爆源位置对冲击波超压分布特征影响有限;与单个爆源中心起爆工况相比,超压相对误差小于5%。

In order to assess the issues of personnel safety and building damage under the impact of tunnel blasting shockwaves,it is necessary to clarify the differences of the propagation characteristics of explosive air shockwaves between construction tunnels and traffic tunnels.A comparative analysis was carried out using the ANSYS/LS-DYNA software to observe the variations of shock wave propagation in single-end and two-way open tunnels.The factors such as the explosive location,the simultaneous detonation of multiple explosives and the blasting source explosive equivalent were investigated.The findings demonstrate that the blast shock wave propagation in the single-head tunnel undergoes a three-stage change pattern from three-dimensional spherical wave to one-dimensional plane wave gradually,and the boundary at the single-head tunnel's end constrains the initial spherical wave diffusion.Additionally,the results demonstrate that the overpressure caused by the wall reflection reaches 20%.The source's explosive equivalent has an impact on the wavefront change.The three-stage change mode of wavefront conversion position and explosive equivalent is a negatively correlated power function,and with the explosive equivalent increases,the conversion is closer to the source location.Multiple explosive sources lead to greater overpressure at near-field,but when it enters into the far-field one-dimensional plane wave propagation region,the influence of multiple explosive and explosive location on the wavefront destruction of characteristics of shock wave overpressure is limited.The relative error of overpressure is less than 5%when compared to the central detonation of a single source.