基于OMA隧道爆破振动下砌体结构的安全评价

以成渝客运专线新红岩隧道上方二层砌体结构为例,采用OMA(运行模态分析)方法研究了砌体结构在隧道爆破引起的地面振动作用下的安全性。结果表明:采用电子雷管爆破相比非电雷管能够有效降低地面振速,峰值振速最多降低约67%;二层砌体结构前4阶固有频率位于9~25Hz,有限元模型修正后其固有频率与实验值的误差明显减小,使其更加符合实际;非线性动力分析表明砌体结构门、窗的角部、砌体与混凝土材料的交界处及底层主应力集中程度高,但砌体的主压应力和主拉应力均小于规范值,表明砌体在爆破振动作用下是安全的,而且电子雷管更适用于结构安全性要求高的隧道爆破;现场调研发现砌体楼房在隧道爆破振动下没有发生损伤,表明基于OMA方法进行隧道爆破振动下砌体结构的安全评价是可行的。

Masonry structure safety evaluation of tunnel blasting vibration based on Operational Modal Analysis

Taking the two-layer masonry structure above the Xinhongyan tunnel of Chengdu-Chongqing passenger dedicated line as an example,the safety of the masonry structure under the ground vibration caused by tunnel blasting was studied by OMA (Operational Modal Analysis).The results showed that the velocity of the peak vibration was reduced about 67 ％ at most using the electronic detonator blasting compared with that of the non-electric detonator.The natural frequency of the first four order masonry structure was 9 to 25 Hz.The error between the natural frequency and the experimental value was obviously reduced after updating the finite element model.The nonlinear dynamic analysis showed that the concentration of the main stress in masonry structure gate,the corner of the window,the junction of the masonry and the concrete material were high,but the main compressive stress and the main tensile stress of the masonry were both smaller than the gauge value,which indicated that the masonry was safe.The electronic detonator was more suitable for the tunnel blasting with high structural safety requirements.The scene investigation found that there was no damage on the masonry under building the tunnel blasting vibration,it was feasible to evaluate the safety of masonry structure under tunnel blasting vibration based on OMA.