混凝土重力坝接触爆炸的响应及破坏特性分析

运用显式非线性动力分析程序LS-DYNA模拟正常蓄水位及空库条件下混凝土重力坝接触爆炸.考虑爆炸荷载作用下混凝土的高应变率的影响，采用HJC(Holmquist-Johnson-Cook)本构模型模拟坝体混凝土的损伤破坏及塑性变形的破坏特性.首先构建炸药-空气-水-混凝土试块模型并对其进行了模型验证.然后构建炸药-空气-库水-坝体-地基之间的动态全耦合模型，并对正常蓄水位与空库条件下TNT炸药接触爆炸的大坝动态响应及破坏特征进行了分析.研究结果表明：运用该方法研究混凝土重力坝水下接触爆炸引起的结构动力响应问题，具有稳定的可靠性，弥补了试验研究的不足.正常蓄水位下，在上游布置炸点对坝体的动力响应及损伤程度影响更大，因此在研究大坝抗爆性能时，应重点关注正常蓄水位条件下大坝上游侧炸点水下接触爆炸时大坝的破坏特性.
In this study, an explicit non-linear analysis program of LS-DYNA was employed to simulate a concrete gravity dam with either normal or empty reservoir under contact explosion. Considering the effect of high strain rate of concrete under the contact explosion, HJC (Holmquist-Johnson-Cook) constitutive model was adopted to simulate the damage characteristic and plastic deformation of the dam. Firstly, “Explosive-Air-Water-Concrete Test Cube” model was constructed and verified. “Explosive-Air-Water Storage-Dam-Foundation” dynamic full coupled model was then developed to evaluate the dynamic response and damage characteristic of the concrete gravity dam under the contact explosion denoted by TNT explosive on both normal water level dam and empty dam. The test shows that the analytical method is reliable to study the contact explosion of the concrete gravity dams, and it also covers the shortage of experimental study. In the case of the normal water level, the dynamic response and the damage of the dam are greatly affected by the explosion points in upstream. Therefore, the study of anti-explosion properties for the concrete gravity dam should focus on the damage measurement when the explosion points are disposed in upstream under the normal water level.