Demolition Blasting Technique for Directional Collapse in Segments of Building with Frame Construction

摘要

Directional collapse of the whole building is mostly adopted in demolition blasting. Although the construction way of this mode is simple and economical, it has its inherent disadvantages. For instance, the blasting charge for single shot cost a lot while the detrimental effect such as blasting vibration, impact vibration, demolition noise and air shock wave became hard to control. It's difficult for structure to disintegrate and the power of backlash was too much. In this paper, the demolition blasting technique for directional collapse of an 8-floor building with frame construction is presented. The relay initiating network with primer detonators, of which delay both in hole inside and outside are combined, is introduced. The building divided into several sections where the delay blasting is initiated in sections respectively. Without transformation of traditional blasting cut, the building collapsed towards a certain side in segments from one section to another. The building fully disintegrated in the air and the segments fell to the ground in turn. This way effectively not only reduced the detrimental impact, but also improved the demolition effect Simultaneity, the control over shape of blast piles is obtained and the backward gets mitigated.