隧道下穿民房爆破振动效应监测

依托右线隧道穿过民房正下方的福建省厦门市石堀山隧道工程,在民房第一、二层墙角处各布置一台自动化爆破振动仪,对爆破开挖引起的振动进行长期监测.结果表明:爆破振速整体上随着测点与掌子面距离的减小而增大;在三向振速中,垂向振速不一定总是最大,但主频小于30 Hz,垂向振速占比最多;分析时应综合振速与主频,选择优势分向振速,或根据建筑物固有频率,选择接近的主频对应的分向振速;当测点与掌子面距离为10~50 m时,爆破振度显著放大,而主频有一定的衰减,径向和垂向主频衰减至与房屋固有频率接近;当测点与掌子面距离为50 m内时,随着掌子面远离测点,振速影响系数C_v先增大后减小,主频影响系数C_f先减小后增大;空洞影响垂向最大,径向次之,切向最小;C_v最大值为3.4,C_f最小值为0.35.

Monitoring on Blasting Vibration Effect of Tunnels Undercrossing Civil Buildings

Relying on the right line of Shijueshan Tunnel Project Xiamen, Fujian undercrossing the civil buildings, an automatic blasting vibration meter was arranged in the corner of the first and second floor of the civil buildings, the long-term vibration monitoring caused by blasting excavation was conducted. The results show that: the blasting vibration velocity increases with the decrease of the distance between the measuring point and the tunnel face on the whole. The vertical velocity in the three-direction velocityies is not always the maximum, but the dominant frequency is less than 30 Hz, and the vertical velocity proportion is the largest. The vibration velocity and dominant frequency should be analyzed together, selecting the dominant directional vibration velocity, or according to the natural frequency of the building, selecting the velocity of directional vibration corresponding to the close main frequency. When the distance between the measuring point and the tunnel face is 10-50 m, the blasting vibration velocity will be significantly amplified, while the main frequency has certain attenuation, the radial and vertical main frequency attenuation are close to the natural frequency of the house. When the distance between the measuring point and the tunnel face <50 m, as the tunnel face moved away from the measurement point, vibration velocity influence coefficient C_v initially increases and then decreases, dominant frequency influence coefficient C_f initially decreases and then increases. The vertical direction of the cavity effect > radial direction > tangential directtion. The maximum value of C_v is 3.4 and the minimum value of C_f is 0.35.