条形药包爆炸破堤的MM-ALE模拟

为了研究爆炸作用下的堤坝破坏形态,基于MM-ALE法(Multi-material ALE method)对某土质堤坝的爆破试验进行了数值模拟,并对堤坝土体中的应力波传播及密度变化规律进行了分析。结果表明:利用MM-ALE模型可以再现堤坝爆炸溃决演化的全过程,且计算结果与现场试验实测数据吻合较好。堤坝坡面及坝顶自由面附近的反射稀疏波和压缩波反复叠加作用是形成爆炸溃口的关键因素;爆炸坑洞演化相对于爆炸应力波传播具有明显的滞后性;爆后堤坝土体被分为爆腔区、压密区和原状土区三个不同的区域,坑口附近压缩带阻止了由水流冲刷引起的连续纵向下切及溃口边坡失稳坍塌引起的间歇横向扩展,局部爆炸压密对保证爆后堤坝整体稳定性具有重要作用。该研究成果可为爆破拆除土坝和堰塞坝等工程应用提供参考。

Numerical Simulation of Dam-blasting Induced by Extended Charges Using MM-ALE Method

In order to study the failure pattern of dams under extended charges, a numerical model based on multi-material ALE method is used to simulate a dam-blasting test, and to analyze the propagation of blast-induced stress waves within soil and the variation of soil density. The results show that the entire evolution process of dam-break induced by explosions can be reproduced by using a MM-ALE model, and the numerical results have good agreement with the experimental data. The repeated superposition of compressional waves and reflection rarefaction waves near the free surface of dam slope and crest is a critical factor in forming blasting burst. The evolution of blast-induced crater exhibits an evident hysteresis relative to the propagation of blasting stress waves. Three regions of the dam are divided after blasting, i.e., cavity zone, compaction zone and undisturbed zone. Densification belt near the crater can prevent continuous vertical incision caused by water erosion and intermittent horizontal expansion caused by collapse or instability of dyke slope. Local compaction induced by blasting plays an important role in keeping global stability of the dam after blasting. The results can provide reference for blasting demolition of embankments or landslide dams.