复杂环境下单塔斜拉桥爆破拆除  

Blasting Demolition of Single-tower Cable-stayed Bridge in Complex Environment

作　　者：李跟 汪高龙 梁来君 夏卫国 LI Gen;WANG Gao-long;LIANG Lai-jun;XIA Wei-guo(Lianyungang Mingda Engineering Blasting Co.,Ltd.,Lianyungang 222021,China;Changzhou Sunan Explosive Building Demolition Co.,Ltd.,Changzhou 213023,China)

机构地区：[1]连云港明达工程爆破有限公司,连云港222021 [2]常州市苏南爆破拆房有限公司,常州213023

出　　处：《爆破》2023年第3期116-122,共7页Blasting

摘　　要：针对复杂环境下单塔钢筋混凝土斜拉桥的爆破拆除,设计了塔柱定向倾倒和主梁原地坍塌的组合拆除方式。中塔柱采用“倒台阶”式切口,切口高度4 m。下塔柱首先采用机械法预处理形成两个宽1.3 m,高4 m的窗口以降低其强度,再布置炮孔进行爆破。主梁与拉索锚固处共设置4处爆破点,采用松动爆破。孔深大于1.2 m的炮孔采用导爆索分段装药结构,有效分散了炸药能量。孔外采用导爆管起爆网路,中塔柱、下塔柱和主梁炸点分为3段起爆。针对桥梁下穿涵洞提出了“刚+柔”复合防护方法。在主梁触地区域设置沙袋减振墙形成柔性防护。同时,沿涵洞走向布置焊接钢制骨架和橡胶垫层形成刚性防护。采用草帘、竹笆和钢丝网对爆破区域进行覆盖防护。起爆后,塔柱向预定方向倾倒,主梁原地坍塌,分为数段,再采用机械法处理。取得了良好的爆破效果,未造成爆破飞石伤害事故,也未对涵洞等建(构)筑物造成冲击破坏。本工程对单塔斜拉桥的爆破设计,以及对下穿涵洞的防护措施可以为相似工程提供借鉴经验。A combined demolition method of directional tilting of main tower and in-situ collapse of bridge beam has been designed for the blasting demolition of a single-tower reinforced concrete cable-stayed bridge in complex environment.An"inverted step"cut with a height of 4 m was designed for the middle tower pillar,and the mechanical pre-processing method was used in the lower tower pillar to form two windows with a width of 1.3 m and a height of 4 m to reduce its strength.The loose blasting was used for the bridge beam at four locations where the cables were anchored on the beam.Decked charge was adopted for the blast holes deeper than 2.1 m and initiated by detonating cords,which effectively dispersed the explosive energy.The middle tower pillar,lower tower pillar and the beam were initiated as 3 stages with nonel detonators.A“rigid+flexible”composite protection method was proposed for the culvert crossing the bridge.Two sandbag damping walls were settled on the touchdown area of the bridge beam to form a"flexible"protection.Meanwhile,a welded steel skeleton and rubber cushion layer were arranged along the direction of the culvert to form the“rigid”protection.Grass curtains,bamboo fences,and steel wire layers were covered on the blasting area.After the blast,the tower toppled on the predetermined direction.And the main beam collapsed in place,divided into several sections which were then processed with mechanical methods.In this project,good blasting results have been achieved without causing flyrock accidents or impact damage to the culvert.

关 键 词：单塔斜拉桥 复合防护方法 控制爆破 钢制骨架防护 倒台阶切口 

分 类 号：TD235.3[矿业工程—矿井建设]