正高程差下边坡爆破对X70钢管振速的影响

Influence of slope blasting on the vibration velocity of X70 steel pipe under positive elevation difference

为了探究正高程差边坡爆炸施工对邻近埋地管道振速的影响,基于商用有限元软件ANSYS/LS-DYNA采用数值模拟方法研究了炸药量相同(30 kg),正高程差不同(2.1、2.6、3.1、3.6、4.1、4.6和5.1 m)时,边坡爆破振动对既有X70管道振速的影响,并与平面地形结果作对比分析。研究表明:相较于平面地形,在水平距离不变的条件下,管道Y方向上会出现振速放大现象,且随着高程增大,振速加快衰减。管道振速放大系数随着高程差的增大呈现先增大后减小的趋势。当高程差为3.1 m时,管道迎爆面测点的振速放大系数最大,为1.998;当高程差为3.6 m时,管道背爆面测点的放大系数最大,为1.622。爆炸地震波在不同的介质界面发生折射和反射所形成的叠加效应以及在坡脚发生绕射,是产生高程放大效应的主要原因。

In order to explore the impact of slope blasting with positive elevation difference construction on the vibration velocity of adjacent buried pipelines,numerical simulation method is used to study the influence of slope blasting on the vibration velocity of X70 steel pipe under the same explosive amount(30 kg)and different positive elevation differences(2.1 m,2.6 m,3.1 m,3.6 m,4.1 m,4.6 m and 5.1 m)by using commercial finite element software ANSYS/LS-DYNA,and comparison analysis is also carried out with plane terrain results.The research showed that,compared with the planar terrain with the same horizontal distance,the velocity amplification phenomenon appear in the Y direction of the pipe,and the velocity attenuation is faster with the elevation increasing.With the increase of elevation difference,the amplification coefficient of vibration velocity(ACVV)on the pipe increases firstly and then decreases.Among them,when the elevation difference is 3.1 m,ACVV on the blasting surface of the pipe is 1.998,which is the largest.When the elevation difference is 3.6 m,ACVV of the back blasting surface of the pipe is the largest,which is 1.622.The superposition effect caused by the refraction and reflection of explosion seismic waves at different medium interfaces and the diffraction at the foot of the slope are the main reasons for the elevation amplification effect.