地铁隧道掘进爆破对既有埋地管道的动力影响

Dynamic Effects of Existing Buried Pipes in Metro Tunnels under Tunnel Excavation Blasting

为研究爆破载荷作用下临近埋地管道的安全性,利用ANSYS/LS-DYNA建立炸药、岩土体、埋地管道的管土耦合模型,对爆破荷载下埋地管道的动力响应进行研究。通过监测管道迎爆面-背爆面特定单元的应力和速度时程曲线,发现距管道两端1/4处的迎爆面存在应力集中现象,背爆面有局部应力放大效应,10~21 ms时管道轴向振动速度最大;通过改变管道的壁厚(4 mm、6 mm、9 mm),得到管道迎-背爆面的轴向有效应力、速度和管道环向振动波能量均随管道壁厚的增加而减小,当管道厚径比i<0.0525时,炸药能的衰减最快,0.0525≤i≤0.05375时,衰减指标η、β、κ数值均为26.7%,且i≥0.06时管道环向监测单元各项衰减指标规律变化趋于一致。

In order to study the safety of buried pipelines under blast load,ANSYS/LS-DYNA is used to establish the coupled model of explosives,geotechnical bodies,and buried pipelines,so as to study the dynamic response of buried pipelines under blast load.By monitoring the pipeline blast surface-back blast surface specific unit stress and velocity time curve,it is found that 1/4 from both ends of the pipeline blast surface and there is a stress concentration,back blast surface has a local stress amplification effect,and the axial vibration velocity of the pipeline reaches the maximum at 10~21 ms;by changing the pipe wall thickness with 4 mm,6 mm and 9 mm,the pipeline meet-back blast surface of the axial effective stress,velocity,and the pipeline annular vibration wave energy are decreasing with the increase in pipe wall thickness.When the pipe thickness ratio i<0.0525,he explosive energy attenuates the fastest.When 0.0525≤i≤0.05375,attenuation indexη,β,κvalues are 26.7%.And when i≥0.06,the pipeline annular monitoring unit of the attenuation index law change tends to be consistent.