The Study On Safety And Rapid Construction Technology Of Blasting Excavation In Condition Of Neighboring Building And Structure

Blasting is widely applied in engineering because of its fast,low-priced and efficiency.With rapid development of infrastructure construction our country,there are many new line in different kinds buildings and facilities,which lead to many nearest-neighbour conditions including parallel,skew and underneath pass.Blasting would influenceneighbor buildings and structure in condition of that environment.Therefore with the methods of field monitoring,literature review,numerical simulation,and blasting test,taking excavation engineering of the Xuhuai station yard of the Xuzhou — Yancheng passenger dedicated railway line as the research background,we studied the safety evaluation,making and implement construction and protection technology of excavation engineering of the Xuhuai station yard,etc.Research conclusion are as follow:(1)We mastered influence factors of excavation engineering of the Xuhuai station yard,and then primarily studied out construction plan by investigation of Xuhuai station yard.On the basis,TAT was introduced to determine dangerous sources,which were primarily determined importance degree;Dangerous sources of TAT were used to make SCA.Standard mark of SCA was determined by importance degree of TAT.We evaluateexcellence of excavation engineering of the Xuhuai station yard,by assessment design,construction and control of the harmful effectof blast vibration of excavation engineering of the Xuhuai station yard.So,blasting design scheme and blasting construction plan were feasible.(2)We used theoretical calculation and numerical calculation to determine that the influence scope of blasting vibration and lyrock was 110 m from 10 kV distribution substation of Beijing-Shanghai High Speed Railway.So mechanical excavation with the help of static blasting was used range distribution substation to 110m;Controlled blasting was used at 110 m away.Neighboring buildings and structures were not effect by blasting vibration during blasting test,Vibration intensity of individualmonitoring point exceeded the limited value during construction period.Safety of neighboring buildings and structures were ensured by optimizing blasting parameters and decreasing blasting range.Finally,we put forward combination construction technology of controlled blasting and mechanical excavation with the help of static blasting.(3)According to environmental characteristics of Xuhuai station yard and influence scope of harmful effects from blasting,we contrapuntally made safety protection plan of Xuhuai station yard:(1)blasting vibration,zoning blasting,millisecond blasting combined with reasonable explosive materials;(2)blasting flyrock,laying “blasting quilts",sandbag and steel-pipe row frame and making buffering dike.(3)blasting noise and shock wave,avoiding construction in gale weather,millisecond blasting,and ensure quality of blasthole and size of line of least resistance that were deviate from neighboring buildings and structures.(4)blasting harmful gas,ensuring qualities of explosives and blasthole,and ventilating and sprinkling after blasting.(4)with the methods of literature review,investigation data and safety precautions,we analysis onmechanism and protective measures of effect of blasting harm from aspects of blasting vibration,blasting flyrock,blasting noise and shock wave and blasting harmful gas,and then conclude a set of blasting protection system that is suitable for neighboring buildings and structures.