钢管爆炸破坏的数值模拟分析与试验研究

在三峡工程二期下游围堰拆除爆破中，其难点问题为混凝土防渗墙的一次性爆破拆除成功。由于混凝土防渗墙内有预埋的灌浆钢管及固定钢管的保持架，这种结构在以往的围堰水下防渗墙爆破拆除工程中是没有先例的。如果混凝土防渗墙爆破拆除仅仅只将混凝土爆碎，而钢管不炸断、保持架不松散则会使爆渣的水下开挖无法进行，因此将混凝土预埋灌浆钢管炸断及保持架炸散是关系到二期下游围堰拆除爆破成败的关键问题。针对这一问题，利用ANSYS/LS-DYNA计算软件和现场试验，研究了不同装药结构、药包直径等因素对钢管爆炸破坏效果的影响，讨论了钢管爆炸炸断破坏形态与装药结构之间的关系，在此基础上确定钢管爆炸炸断破坏的合理爆破参数及装药结构形式。二期围堰爆破拆除结果表明研究成果是可靠的。

Test study and numerical simulation analysis of explosion in steel tubes

To demolish concrete cutoff wall successfully in one blasting is a difficulty which arose in the demolition blasting of downstream cofferdams in the second stage of Three Gorges Project (TGP). The problem was caused by grouting steel tubes and supports to immobilize them, both of which were pre-buried in concrete cutoff wall. This kind of structure was never encountered before in demolition blasting of cofferdams’ underwater cutoff wall. If the demolition blasting just exploded concrete into pieces, leaving those steel tubes unbroken and their supports compact, the underwater excavation of explosion residues could not proceed. The key element of the demolition blasting of downstream cofferdams in the second stage was to destroy both the grouting steel tubes and their supports. To solve this problem, this paper used ANSYS/LS-DYNA computational software and in-situ experiments to study the effects of different charge structures and diameters of cartridges on the destruction of steel tubes in explosions. The relationships between the destruction configurations of steel tubes after explosions and charge structures are discussed; and the proper blasting parameters and charge structure are determined based on these discussions. The research achievements are proved by the results of the demolition blasting.