Aiming at the blasting demolition of two adjacent boiler houses with reinforced concrete-steel composite frames in a power plant, systematic analysis was conducted on their structural characteristics and surrounding environmental conditions.analysis reveals significant structural vulnerabilities, including strong coupling effects, imbalanced aspect ratios, and risks of center-of-gravity deviation, compounded by complex site conditions and strict safety requirements for demolition operations. To address these engineering challenges, the research employed rigid-body center-of-gravity synthesis theory to segment structural mass units and precisely calculate the boiler houses′ center of gravity at approximately 36 meters in height. By integrating the collapse geometric model of coupled frame structures with empirical engineering formulas, critical blasting cut parameters were determined. Following the weak-column-strong-beam design principle, the blasting parameters of RC columns were optimized. Artificial pre-cutting technology severed hidden load-transfer paths between the two buildings, ensuring synchronous destabilization of the RC and steel structural systems. Additionally, increasing inter-row delay time (2nd to 3rd columns) to 1 second facilitated supporting-point forward displacement, effectively preventing boiler house structural arrest due to insufficient aspect ratios. A 2~3 second delay interval was implemented between the two boiler houses to prevent superposition of vibration energy, while an integrated protective system was employed to mitigate blasting-induced hazards. Field tests confirmed both structures collapsed precisely along predetermined trajectories with compact debris piles and complete structural fragmentation. Measured blasting and collapse vibration velocities remained below safety thresholds, with no incidents of flying rock or adjacent structure damage. These results successfully address critical technical challenges in the demolition of multi-boiler houses in dense environments, establishing reliable engineering references for comparable projects.

This study addresses the blasting demolition of an 18-story oval frame-core tube structure. Systematic analysis revealed that the structure′s small height-width ratio and long span contribute to potential instability and collapse, with uneven stress distribution due to irregular shear wall placement within the core tube. To mitigate these challenges, delayed blasting and auxiliary weakening techniques were employed. The approach included pre-treatments such as splitting and cutting to transform the cylindrical structure into a wall-like form, reducing deviation during collapse. The building was divided into four blasting zones with increasing delay times, particularly extending the delay for the last two zones by 1 second to ensure sequential support point failure and prevent incomplete collapse. Additionally, the upper and lower double-incision folding blasting method was utilized to control vibration upon ground impact and enhance overall dissociation. The demolition process, lasting approximately 5 seconds, resulted in the building collapsing primarily along the designed direction with minimal backseat movement and evident structural failures. The sequential floor folding and concentrated pile blasting demonstrated effective demolition.

In order to demolish a 57 m high double-cylinder ammonium nitrate granulation tower in a complex environment, this study analyzes the structural characteristics of the tower, including its large potential energy and uneven mass distribution. A blasting method was designed with intermediate initiation and sequential detonation towards both sides to achieve a controlled collapse effect through “directional blasting+internal convergence”. The blasting design includes trapezoidal cut notches with strictly controlled perimeter and height. The bottom supporting walls are partially retained, and highly symmetric directional windows were created at specific heights. The demolition was carried out using high-precision nonel detonators combined with delayed initiation inside the holes and external relays outside the holes. Through theoretical analysis and calculations, the final blast notch length was determined as 13.5 m with a height of 3.5 m. To validate the design scheme, LS-DYNA simulation software was used to establish a three-dimensional finite element model of the granulation tower for pre-collapse analysis. Simulation results show that the collapse process takes approximately 8.8 seconds without any significant forward movement or toppling during collapse, indicating that the overall blasting parameters selected in this scheme are reasonable and can achieve the desired demolition effect.