混凝土围堰拆除爆破对大坝的安全影响分析

西安科技大学 建筑与土木工程学院,陕西 西安 710054

拆除爆破; 混凝土围堰; 爆破振动; 质点振动速度; 回归分析

Influence of the concrete coffer demolition blasting on the dam safety
WANG Xiao-lin,JIN Long,ZENG Qing-yuan,ZAN Biao

(College of Civil and Architectural Engineering,Xi'an University of Science and Technology,Xi'an 710054,China)

demolition blasting; concrete coffer; blasting vibration; particle vibration dynamic speed; regression analysis

DOI: 10.13800/j.cnki.xakjdxxb.2015.0103

备注

以位于长江中游支流沅江干流的某水电站混凝土围堰拆除爆破为工程背景,需要爆破拆除的混凝土围堰与县城的直线距离不超过2 km,与最近的一条坝顶公路桥的最小距离为3 m,所以控制爆破振动势必对本工程有着重要的意义。通过对该工程现场爆破试验进行质点振动监测,测取离爆源不同位置下的质点振动速度的监测数据,同时采用回归分析法对数据进行分析,得出爆破地震波在钢筋混凝土大坝结构中的衰减规律,结果表明,使用分段微差爆破技术可有效控制拆除爆破对大坝的振动影响; 依据《爆破安全规程》对钢筋混凝土结构质点安全振动速度的要求(v≤5 cm/s),证明试验爆破初步设计方案及爆破参数k,α较为合理,可为后期爆破方案确定和保证坝体安全稳定性提供依据,也可为类似工程提供工程经验。综合以上试验爆破参数和监测数据得出以下建议:最大单响药量控制在27 kg以下; 需要采取一些外在减震措施; 要注意地震波的主频率变化范围,防止共振现象的发生。

Taking a demolition blasting of hydropower concrete coffer as engineering background,which is located in the Yangtze tributary Ruanjing river,concrete coffer needed to be demolition blasted is not over 2 km in linear distance from the town and the minimum distance is 3 m from the nearest dam bridge.So,controlling the blasting vibration is bound to have important significance to the project.Though monitoring the blasting particle vibration in field,acquiring the monitoring data of vibration speed from different locations and using regression analysis to analyze the data,we obtained the blasting seismic wave attenuation rule in reinforced concrete dam.The result shows that millisecond blasting technique could control the affect of the demolition blasting on the dam through effectively; According to Safety Regulations for Blasting,the demand of structure safety vibration velocity(v≤5 cm/s)on reinforced concrete prove that the preliminary design of blasting and blasting parameters are reasonable,which offer evidence for the confirmation of later blasting,security and stability of the dam.At the same time,offer some experience on the similar project.Based on the above blasting parameters and monitoring data on the test,we have the following suggestions:the explosive quantity should be under 27 kg, some exterior seismic resistance measures should be taken, to pay attention to the main frequency of seismic wave range,and prevent the occurrence of resonance phenomena.