砖烟囱爆破拆除不同切口形状的数值模拟

针对烟囱爆破拆除时爆破切口形状的确定往往按经验确定,没有重视烟囱倒塌过程中一些问题很难通过理论预见的情况,利用ANSYS/LS-DYNA软件数值模拟了常见的长方形切口、正梯形切口、倒梯形切口这3种爆破切口形状对烟囱倒塌拆除过程并进行了对比和分析,研究结果表明:首先从爆破切口闭合时间看到,倒梯形切口闭合时间最长,正梯形切口闭合时间次之,长方形切口闭合时间最短。其次从烟囱顶端着地时间分析,正梯形切口烟囱顶端着地时间最长,而其它两种切口方案次之,并且这两种方案对烟囱倒塌时间差不多相等。再从模拟烟囱倒塌的过程分析,正梯形切口及长方形切口烟囱倒塌过程出现"后座"现象。最后从烟囱倒塌顶端速度变化曲线中看出正梯形切口烟囱倒塌方案对地面的冲击力最小,引起地面的振动强度最小。

Numerical simulation study on the removal of chimney with different blasting notch shape

The shape of the blasting notch in the chimney blasting was often determined empirically.Some problems that could not be predicted by the theory of chimney collapse could be ignored.ANSYS/LS-DYNA software was used to simulate the common rectangular notch,trapezoidal notch and inverted trapezoidal notch.The results showed that the closing time of the trapezoidal notch was the longest,trapezoidal notch closure time followed by rectangular notch closed the shortest time.Secondly,from the end of the chimney to the ground time analysis,the main trapezoidal chimney had the longest landing time,while the other two notches programs were the second,and the two schemes were almost equal to the collapse time of the chimney.And then from the simulation of the chimney collapse process analysis,the trapezoidal notch and rectangular notch chimney collapse process appeared " back seat" phenomenon.Finally,the chimney collapse tip velocity curve showed that the positive trapezoidal notch chimney collapse program on the ground impact of the smallest,causing the minimum ground vibration intensity.