钻爆法地铁隧道开挖对地下管线的影响

EFFECT OF SUBWAY TUNNEL EXCAVATION BY DRILL-BLASTING METHOD ON PIPELINE

钻爆法地铁隧道施工对临近管线的影响目前研究较少。利用FLAC3D软件施加爆破荷载,研究地铁隧道开挖时周边管线的应力位移的变化。通过改变地表振速来体现爆破荷载的变化,研究不同爆破强度下管线应力位移的变化。同时在研究中,考虑管线与隧道平行及管线与隧道垂直两种位置关系。研究结果表明：由于管线对地层沉降的抵抗作用,当管线与隧道垂直时,管线的竖向位移小于二者相平行时的,但拉压应力大于二者相平行时的;地表振速在1.2~2.4cm/s时,管线内拉压应力增长迅速,当振速达到2.7cm/s,管线拉应力并未达到接头填料拉应力限值;振速在1.45~2.0cm/s范围内,管线位移增大明显,振速达到2.7cm/s后,管线竖向位移超过工程限值;随着地表振速的增大,管线竖向位移斜率不断增大。管隧平行时,振速增大到2.3cm/s后,位移斜率增长速度加快。

The study on pipeline under drill-blasting tunnel excavation is not enough now. The stress and displacement of pipeline was studied under drill-blasting excavation, when blasting load was considered in FLAC3D software. Vibration velocity was used to reflect the intensity of blasting in the study and stress and displacement of pipeline were studied under different blasting velocities. The stress and displacement of pipeline were considered when pipeline and tunnel were horizontal and vertical. It showed that, the posi- tion of pipeline and tunnel was important when considering the displacement and stress of pipeline. Because of the resistance from pipeline on stratum movement, when the position was vertical, displacement of pipeline was less than the horizontal. When the position was vertical, tension and compression stress of pipeline were bigger than the horizontal. When the vibration velocity grew from 1.2cm/s to 2.4cm/s, the tension and compression stress growed rapidly. When the velocity grew to 2.7cm/s,the tension stress was still less than the limit of materials of packing. When the vibration velocity in range of 1.45 cm/s 2.0cm/s, the displacement of pipeline growed rapidly. When the velocity grew to 2. 7cm/s, the displacement of pipeline was bigger than the limit in engineering. The slop of pipeline increased with the growth of velocity. After the velocity reached 2.3cm/s, the slop increased rapidly when pipeline and tunnel were horizontal.