水下爆炸冲击下箱型隧道结构破坏试验及数值模拟

Structural Damage Tests and Numerical Simulation of Box Tunnel by Underwater Blast Impact

针对水下爆炸荷载作用下混凝土隧道结构的动态响应、损伤演化及其破坏问题,本文采取室内模型试验与数值计算相结合的方法,根据东湖水下隧道设计了比尺为40∶1的试件,开展了水下箱型混凝土隧道缩比模型的爆炸试验,通过监测应变信号,比较了不同乳化炸药当量下混凝土隧道试件的动态响应规律,通过测量破坏范围的大小、裂缝扩展的长度,调查了箱型隧道缩比模型试件在水下爆破荷载作用下的破坏形式;采用ANSYS/LSDYNA中S-ALE算法对试验进行了1∶1建模仿真分析,对照试验数据及破坏形态,发现模拟结果与试验结果基本一致,同时对仿真结果进一步分析得到了水下爆炸冲击波的传播完整过程和试件结构的变形规律,通过对测点应变、位移数据的统计分析,揭示了箱型隧道试件在爆炸荷载下的动态响应机理。结果表明:箱型混凝土隧道结构在横向上的应变远大于纵向上应变;隧道破坏位置主要集中在爆源附近区域以及结构转角位置,验证了S-ALE算法能够较为准确的模拟出水下爆炸下结构的动态响应及损伤演化。

In order to investigate the dynamic response,damage evolution and failure of concrete tunnel structure by underwater explosion load,laboratory tests and numerical calculations are adopted in this paper.Firstly,a 40:1 specimen was designed according to the East Lake underwater tunnel.An explosion test of the underwater box con-crete tunnel model was then carried out.The dynamic response rule of the concrete specimens under different emul-sion explosive equivalent was compared by monitoring the strains:Meanwhile,the failure forms of the scaled model of the box tunnel caused by the underwater blasting load were investigated by measuring the size of the failure range and the length of crack propagation.Furthermore,a 1:1 modeling simulation analysis of the test was carried out using the S-ALE algorithm in ANSYS/LSDYNA.It is found that the simulation results were basically consistent with the exper-imental results by comparing the experimental data and failure patterns.At the same time,the complete propagation process of the underwater explosion shock wave and the deformation law of the specimen structure were obtained by further analysis of the simulation results.Finally,the dynamic response mechanism of the box tunnel specimens under explosion load was revealed through statistical analysis of strain and displacement data at the measuring points.The results show that the transverse strain of the box concrete tunnel structure is much larger than the longitudinal strain.The failure location of the tunnel is mainly concentrated in the area near the explosion source and the structural angle position.It is verified that the S-ALE algorithm can simulate the dynamic response and damage evolution of the struc-ture by underwater explosion accurately.