高耸建筑物定向爆破倾倒时的后座及其对策

高耸建筑物定向爆破倾倒时,对周围保留建筑物、设施等的安全性产生影响的危害效应之一是后座问题。研究和探讨后座现象以及提出预防措施,对高耸建筑物在有限坍塌范围的复杂环境中,爆破拆除时安全性预测及合理选择爆破参数、确保良好的爆破效果将有很大帮助。本文通过对不同类型的高耸建筑物。文中分为两类:一类是筒式支撑的烟囱、水塔等;另一类是钢筋混凝土框架结构或砖混楼房、框架支撑的水塔等)在定向爆破倾倒过程中个同阶段的力学分析,较全面地讨论了后座产生的原因、现象及可能出现的后座范围。

RECOIL OF TOWERING CONSTRUCTION OF BURSTING DEMOLISHED BY DIRECTIONAL BLASTING AND APPROPRIATE MEASURES

Recoil of towering constructions of bursting in directional blasting potentially has harm effects to the preserved buildings, installations and facilities. Studies on the recoil will bring much helps to estimate the reliable safety and optimization of choosing parameters of directional blasting in the limited collapsing area with complicated surroundings. This paper presents the mechanical analysis in different collapsing stages of various towering constructions (tube-supported such as chimney or water tower etc. ceinforced concrete such as frame structural and concrete masonry building, frame supported water tower etc.). comprehensively discusses the causes of recoil phenomena and the possible recoil area.In mechanical analysis, some schematic diagrams show the loading states of the demolished towering constructions, the relevant analysis formulas and their imbalance conditions are given. These may be helpful to optimize the parameters of blasting planning and provide some theoretical basis. On the basis of these analysis and engineering experiences of the author and other persons, some safety measures for planning blasting are suggested. The main measure against recoil in demolishing tube chimney or water tower is to ensure that the non-demolijhed part of the wall of the towering construction at the moment of blasting has e-nough strength and stability to support itself, which depends upon the blasting cut shape, its dimension and place on the wall,charge amount and the structure of the construction. As to the frame construction, the author proposes to control the heights of blasting and the bursting time in both falling and backward directions. Some examples are given.