Integrated Control Technology for Recoil and Ground Impact Vibration in Directional Blasting-induced Collapse of Frame-structured Buildings

With the increasing complexity of the urban environment and environmental awareness of the public, directional toppling blasting demolition of frame structure buildings often encounters the problems of large collapse recoil distance and strong ground impact vibration, which limits the development and application of blasting demolition technology. To control the collapse recoil and touchdown vibration of the directional blasting demolition of the frame structure building, the design method of the hinge point forward high blasting cutting was put forward, and the theoretical calculation model of blasting cutting height was established based on traditional bottom cutting blasting demolition technology. Meanwhile, a blasting demolition technology of high-cutting blasting with a reserved buffer layer was developed combined with engineering practice. Three kinds of blasting cutting forms were designed to meet the control requirements of different degrees of collapse recoil and touchdown vibration according to the treatment method of the reserved buffer layer. Furthermore, the collapse and disintegration effects of frame structure blasting demolition in different blasting schemes are compared and analyzed by theoretical analysis, numerical simulation, and field test. The results show that the hinge point forward high blasting cutting can increase the inclination angle, prolong closure time, and control the structure’s collapse recoil and touchdown vibration, greatly improving the reliability of structural instability and collapse. Compared with the traditional bottom-cutting blasting scheme, the reserved buffer layer hinge point forward high-cutting blasting scheme can effectively shorten the length of the blasting pile, reduce the speed of structural collapse to the ground, and effectively control the height of the blasting pile. The selection of a reserve buffer layer should be considered comprehensively with the structural characteristics of the building and the surrounding environment.