烟囱高位组合切口定向爆破倒塌过程数值研究

发布时间：2018-05-04 05:22

本文选题：钢筋混凝土烟囱 + 高位切口　；参考：《振动与冲击》2017年15期

【摘要】：针对复杂环境下爆破切口高度在百米位置的烟囱定向爆破拆除工程,为研究正三角矩形与倒三角矩形组合切口对烟囱爆破拆除倒塌及受力过程的影响,结合实际工程,利用LS-DYNA有限元软件分别建立两种切口形状下钢筋混凝土分离式共节点烟囱模型,对烟囱倒塌及受力过程进行了系统研究。结果表明,爆破切口形成后,约2~3 s的中性轴稳定时间(切口系数K=0.56~0.58)是烟囱不出现过早下坐和形成定向倾倒趋势的关键条件;支撑部位内侧混凝土承受的压应力要大于外侧混凝土,倒三角矩形较正三角矩形组合切口能够延迟切口角端压剪破坏的发生,延缓支撑部位中性轴后移速度以及使支撑部位承受较高压应力,有利于烟囱避免过早下坐和安全精确定向;由于倒三角矩形组合切口与倒梯形、倒三角梯形组合切口具有一定共性,烟囱高位切口定向爆破切口形状建议优先采用倒三角型切口。
[Abstract]:In view of the directional blasting demolition of chimney with the height of blasting cut at 100 meters in complex environment, in order to study the influence of the combined cut of square triangle rectangle and inverted triangle rectangle on the process of demolition collapse and force of chimney blasting, combined with the actual engineering, The LS-DYNA finite element software is used to establish the separated common node chimney model of reinforced concrete under two different notches, and the collapse and stress process of the chimney are studied systematically. The results show that the stable time of neutral axis about 2 ~ 3 s (cut coefficient K _ (0.56) ~ (0.58)) is the key condition for the chimney not to sit down prematurely and to form the trend of directional toppling after the formation of blasting cut. The compressive stress of the inner concrete in the supporting part is greater than that in the outside concrete, and the compression shear failure at the corner end of the incision can be delayed by the reverse triangle rectangle than the positive triangle rectangle combined incision. Delaying the speed of neutral axis moving backward and bearing the support part under high pressure will help the chimney avoid prematurely sitting down and safely and accurately orienting. Because of the inverted triangle rectangle combined incision and inverted trapezoid shape, The inverted triangle trapezoid combined cut has certain commonness, and the shape of the chimney high cut directional blasting is preferred to adopt the inverted triangle cut.
【作者单位】：中国矿业大学(北京)力学与建筑工程学院;河南理工大学土木工程学院;
【基金】：国家自然科学基金(51474218)
【分类号】：TU746.5

【相似文献】