Research On Green Demolition Blasting Technology For Embedded Holes Of Reinforced Concrete Bars

Since the reform and opening up,my country’s economy has grown by leaps and bounds,and the process of urbanization has been accelerating.With the acceleration of urbanization,more and more buildings(structures)need to be demolished.As the skeleton of the building,reinforced concrete members are the main load-bearing components,and they are also the key and difficult points for demolition.Blasting demolition is the mainstream means of demolition of reinforced concrete members.Under the background of the continuous deepening of green and environmental protection concepts in the field of engineering construction,its shortcomings such as high drilling costs and significant harmful effects have become increasingly prominent.In order to overcome these shortcomings,we proposed a new concept of greening demolition and blasting and invented a series of new green demolition blasting technologies.Based on these new technologies,this paper systematically studies four issues: the layout of embedded holes,the construction technology of embedded holes,the mechanical influence of embedded holes on reinforced concrete members,and the optimization of the charge structure.mainly includes:(1)On the basis of the existing embedded concept and practice,the layout method and parameter design of the vertical and axial embedded holes of reinforced concrete members have been further improved.(2)On the basis of the existing engineering practice,the construction technology for the demolition of embedded holes for blasting is summarized,from the construction cost(drilling,plugging and tying of embedded pipes)and the cost of material consumption(detonators,detonating cords and embedded pipes).The angle of tube),the technical and economic comparison of the three types of blastholes:mechanical drilling,vertical embedded holes and axial embedded holes,highlights the economics of axial embedded holes.(3)The non-linear finite element analysis software abaqus is used to compare and study the axially embedded reinforced concrete members and solid reinforced concrete members,and calculate and analyze the influence of the embedded holes on the mechanical properties of reinforced concrete members.The results show that the existence of embedded holes weakens the mechanical properties of reinforced concrete members,and the flexural,shear and compressive bearing capacities are reduced by15%,5% and 6%,respectively.This further demonstrates the reinforced concrete members from the perspective of statics.The feasibility of arranging embedded holes in axial direction.(4)Taking the cast-in-place reinforced concrete beam as the research object,taking the type of spacer medium,the number of charge column segments,and the type of blocking material as three factors,three levels are set respectively to monitor the indicators of blasting vibration,blasting noise and bulk rate.Orthogonal test.Discuss the influence of various factors on the blasting effect and harmful effects,and then optimize the charge structure.The results show that the spacing medium is the most sensitive factor affecting the three indicators.The optimal combination at different levels is found only from a single indicator consideration.Based on the comprehensive consideration of the three indicators,the water bag spacing,4-stage grain charge and cuttings are selected.The blasting demolition of reinforced concrete beams with blocked charges has the best effect.This research is meaningful to further improve the green demolition blasting theory and practice of reinforced concrete members.