【摘要】 针对老桥在拓宽改造期间两侧拼宽新桥已运营条件下的拆除工程特点,提出了逐跨延时原地缓冲坍塌控制爆破方案,运用计算机数值模拟计算方法,优化确定起爆顺序与延时时间、预处理方案,预测爆破与塌落全过程及对新桥安全性影响;以桥梁受力特点分析为依据选取了爆破部位,确定了浅孔结合深孔的钻孔方式,对于复杂材质承压结构的深孔,提出了"一孔三段"装药结构的设计思路;结合数值模拟分析与"单响药量控制优先"原则,设计了多单元复式导爆管雷管起爆网路,介绍了"悬空式多回路"联网的施工作业方法;在确定新桥爆破振动和塌落振动的控制标准的同时,利用数值模拟和理论公式进行了安全校核。该技术可为类似工程的前期设计优化与最终工程实践提供参考。更多还原

【Abstract】 Point at the engineering characteristics of the old bridge demolition under the condition that the new bridge has been operated on both sides during the extension and reconstruct project of the bridge, the controlled blasting scheme for vertical buffering collapse with span-by-span time delaying was proposed. By means of computer numerical simulation calculation method, initiation sequence, delay time and pretreatment scheme were optimized and determined, while the whole process of blasting and collapse and the safety impact of new bridges were predicted. Based on the analysis of the characteristics of bridge stress, the blasting sites were designed and selected, and the drilling mode of shallow holes combined with deep holes was determined. For the deep holes of pressure-bearing structure with complex material, the design idea of charge structure that one hole with three sections was put forward. Combined with numerical simulation analysis and the single initiation eplosive control priority principle, the multi-unit multiple initiation network with the non-electric detonator was designed, and the operation method of suspended multi-loop network was introduced. While the control standard of blasting and collapse vibration of new bridge was determined, the safety check was carried out by numerical simulation and theoretical formula. This technology can provide reference for pre-design optimization and final engineering practice of similar projects.更多还原