沌阳高架桥爆破拆除塌落引起的地面振动特征

Characteristics of ground vibration caused by blasting demolition collapse of zhuanyang viaduct

利用实测结果分析了桥梁爆破拆除塌落引起的地面振动加速度特征,结论如下:桥梁塌落地面振动加速度峰值随距离增大而降低,竖向分量加速度峰值显著大于水平分量,随距离增大差别变小;测线1的地面振动加速度峰值频率随距离增加呈指数降低趋势,受叠加效应影响,测线2和测线3的地面振动加速度峰值频率随距离的变化规律不明显;测线1的切向振动分量的峰值频率最高,测线2次之,测线3最低;地面振动加速度持时随距离增加而变长,水平分量持时大于竖向分量;减振措施在降低爆破塌落振动峰值的同时也会降低地面振动峰值频率、延长其持时;多个桥联连续塌落产生的叠加效应使得地面振动加速度峰值增加、峰值频率降低,不利于建筑结构安全。

Based on measured results, the ground vibration acceleration characteristics caused by blasting demolition collapse of Dunyang viaduct were analyzed. The conclusions were that the peak of ground vibration acceleration decreases with increase in distance; the acceleration peak of vertical component is greater than that of horizontal one,but the difference becomes smaller in the far field; the peak frequency of the ground vibration acceleration measured on line 1 drops exponentially with increase in distance,but the same trend is not found on measuring line 2 and line 3; the peak frequency of tangential component of ground vibration acceleration is the highest on line 1,that on line 2 is higher and that on line 3 is the lowest; the duration of ground vibration acceleration increases with increase in distance,and the duration of its horizontal component is longer than that of its vertical component; vibration reduction measures can reduce the peak value of ground vibration acceleration,and at the same time reduce the peak frequency and lengthen the duration of ground vibration acceleration; the vibration superposition effect of continuous collapse of multiple bridge spans increases the peak value of ground vibration acceleration and reduces the peak frequency,that is adverse to the building security.