210m烟筒同向折叠爆破降振效果分析  

Damping Effect Analysis of Same Direction Folding Blasting for 210 m High Chimney

作　　者：于淑宝[1,2] 汪旭光 YU Shu-bao;WANG Xu-guang(School of Mechanics and Civil Engineering,China University of Mining and Technology,Beijing 100083,China;Tangshan Jinyu Blasting Engineering Co Ltd,Tangshan 063020,China)

机构地区：[1]中国矿业大学(北京)力学与建筑工程学院,北京100083 [2]唐山金宇爆破工程有限公司,唐山063020

出　　处：《爆破》2020年第2期60-68,74,共10页Blasting

基　　金：国家自然科学基金(50704005)。

摘　　要：高耸烟筒爆破拆除多采用定向倾倒、反向折叠、分段爆破等方法。烟筒筒体倒塌过程产生的较大触地振动长期以来是个难以克服的问题,尤其是势能较大的烟筒上部在倾倒下落过程产生巨大的冲量,势必造成较大的地面振动。该项研究是利用数值模拟分析和爆破切口部位的应力变化分析,通过对延期时间2 s、3 s、5 s时上部切口压应力、拉应力的不同切口闭合情况,确定上下两段同向折叠爆破合理的间隔时间为3 s。通过对上部切口爆破震动衰减公式拟合与下部切口爆破震动衰减公式拟合及烟筒塌落振动衰减公式拟合,与相关工程经验值比较得出,当地面采取挖沟槽、垒筑土墙减震措施时可减震70%。结合工程实例,采用同向折叠的爆破技术拆除210 m高钢筋混凝土超高烟筒。在110 m高检修平台处开设上部爆破切口,使重达1770 t的烟筒上部筒体在爆破切口背面产生铰链结构与剪切共同作用,在重力作用下撞击下部筒体产生破碎,从而实现空中解体。在上部切口爆破后,上部100 m烟筒迅速下切下座,与下部110 m烟筒筒体沿设计方向倾倒呈现出少有的后座下切塌落现象,达到了很好的降振效果。The methods of directional collapse,reverse folding and segmented blasting are widely used in the demolition of high-rise chimneys by blasting.The large ground vibrations caused by the collapse of a chimney is a difficult problem to overcome for a long time.In particular,the upper part of the chimney with higher potential energy has a huge impulse in the process of toppling and falling,which is bound to cause greater ground vibration.The study is based on the numerical simulation analysis and the stress change analysis of the blasting incision position.According to different closure incisions of the upper incision under compressive stress and tensile stress at the delay times of 2 s,3 s and 5 s,it is determined that a reasonable interval time between the upper and lower sections of a folding blasting in the same direction is 3 s.By fitting the vibration attenuation formulas of upper and lower incision blasting and the formula of flue tube collapse,it is concluded from the comparison with the relevant engineering experience value that 70%of the vibration can be reduced when trench excavation and earth wall construction are adopted on the ground.Combining with engineering examples,a 210 m super-high reinforced concrete chimney is removed by using the same direction folding blasting technique.The upper blasting incision is set up at 110 m high maintenance platform,which makes the upper cylinder of the chimney with a weight of 1770 t produce joint effect of the hinge structure and shear on the back of the blasting incision,and breaks the lower cylinder under the impact of gravity,thus realizing aerial disintegration.After the upper incision blasting,the upper 100 m chimney was cut down rapidly,and the lower 110 m chimney was tipped down along the design direction,showing a rare phenomenon of back-seat down-cutting collapse,which achieved a good vibration reduction effect.The vibration attenuation formula of collapse touching the ground has engineering characteristics,research value and engineering reference significa

关 键 词：同向折叠 超高烟筒 爆破拆除 触地振动 

分 类 号：TU746.5[建筑科学—建筑技术科学] TB41[一般工业技术]