隧道爆破地震下输气管道动力响应数值试验

Numerical Experiments of Dynamic Response of Buried Gas Pipeline under the Action of Seismic Waves Induced by Tunnel Blasting

为合理确定爆破地震作用下埋地输气管道安全振动控制标准,明确管道运行参数对其动力响应的影响规律.以下穿既有输气管道的隧道爆破工程为背景,基于非线性动力有限元模拟方法和正交试验原理进行输气管道动力响应数值试验,按照极差分析方法确定埋地管道直径、厚度、管道埋深、管道与隧道净距、运行内压等5个因素对管道应力与振速响应特征的影响次序.研究结果表明:管道最大主应力峰值主要受管道内压、壁厚影响,并与管道内压呈明显的线性关系;爆破地震作用下运行内压为7 MPa管道的最大主应力峰值为290.73 MPa,其最大拉应变为0.001 4,小于管材的极限弹性应变0.002 3;输气管道的动力响应特征主要与管道的结构有关,爆破地震引起的管道动应力小于管道容许应力的6%;输气管道的最大动应力可采用空管的动态最大主应力峰值与其有压时的静态主应力的叠加值估算.

In order to re a sonably determine the vibrat ion control s tandard of bur ied gas transmis sion pipeline under the action of seismic waves from blasting, it is important to clarify how the operating parameters of pipeline affect its dynamic response. Taking Xiannvyan tunnel blasting project as example （the tunnel passes beneath a buried gas pipeline）,and based on the non-linear dynamic finite element method and the principle of the orthogonal experiment, the numerical experiments on the dynamic response of a buried gas pipeline were carried out. Using the range analysis method,five parameters of pipeline including the outside diameter,wall th ic k n e s s, b u r ied d e p th, c le a r d is tan c e between pipeline center and tunnel top as well as operating internal pressure were sorted according to their effects on the response characteristics of pipe stress and vibration velocity . The results show that the peak of the maximum principal stress is mainly affected by the operating internal pipeline pressure and wall thickness,wh ich has obviously linear relationship with th e operating internal pressure . Underthe action of blasting-induced seismic waves, when the operating internal pressure is 7 MPa, the peak of maximum principal stress is 290. 73 MPa and the maximum tensile strain is 0. 001 4, which is less than the elastic strain limit of gas pipeline 0. 002 3. The characteristics of the pipeline dynamic response mainly depend on its structure, and the pipeline dynamic stress caused by blasting vibration is less than 6% of pipeline allowable stress. The maximum dynamic stress of the gas pipeline can be estimated by the superposing the dynamic maximum principal stress of the pipeline without operating pressure and its static principal stress with operating pressure.