爆破振动下埋地天然气管道工况参数对管土振动特征的影响分析

发布时间：2018-05-02 05:01

本文选题：埋地天然气管道 + 隧道爆破振动　；参考：《西南交通大学》2017年硕士论文

【摘要】：管道运输是五大输运方法之一,埋地管道以其运输的经济和高效性被用于长距离输送天然气。随着我国各地基础设施的建设,爆破技术已广泛应用于隧道、路基等工程开挖施工中,爆破产生的地震效应可能对附近埋地管道安全构成影响。因此,有必要进行爆破地震作用下埋地管道及其地表的振动特征相关研究,为优化爆破参数和建立爆破振动监测标准以确保埋地管道安全运行提供理论基础。以下穿兰成渝埋地天然气管道的西成客运专线仙女岩隧道出口段掘进爆破工程为背景,建立包含管道、岩石、土体、天然气和炸药在内的三维动力有限元计算模型,在验证模型计算结果的准确性基础上,分析爆破振动下埋地天然气管道的管径、壁厚和埋深等参数对管道及地表振动特征和管道Von-Mises应力的影响规律。按照现场管道与隧道的位置关系、工程地质和爆破条件建立的三维动力有限元数值计算模型能较好地模拟管道及其地表的振动状态,其模拟得到的地震波形与相应位置处的实测地震波具有较高的相似度,振动强度计算值与实测值的相对误差小于11%。当隧道埋深41.5m、隧道爆破的当量装药量25kg时,岩体质点的竖向振速随着与爆源距离的增大而减小,且表现为距爆源越远、其衰减越为缓慢,在爆源上方岩土界面处的振动速度衰减至3cm/s左右;土体振速分别在管道附近以及地表存在两个极值点。进一步分析不同管径、壁厚和埋深等参数时的管道与土体的动力响应结果发现,管道壁厚增加,管道质点峰值振速减小,而地表土体的振速基本不变;随着管道内径增加,管道的质点峰值振速增加,地表振速也随之减小;相同管道内压下管径与壁厚的比值对于管道的Von-Mises应力具有较大影响,管道埋深的影响则基本没有;管道埋深增大,管道质点峰值振速减小,但管道上方地表土体质点的振速增大。
[Abstract]:Pipeline transportation is one of the five major transportation methods. Buried pipeline is used for long distance transportation of natural gas because of its economy and efficiency. With the construction of infrastructure in various parts of China, blasting technology has been widely used in the excavation of tunnels, subgrade and other projects. The seismic effect caused by blasting may affect the safety of buried pipelines nearby. Therefore, it is necessary to study the vibration characteristics of buried pipeline and its surface under blasting earthquake, so as to provide a theoretical basis for optimizing blasting parameters and establishing blasting vibration monitoring standard to ensure the safe operation of buried pipeline. Under the background of the blasting project of Xianyan Tunnel exit section of Xiancheng passenger dedicated Line, which passes through Lanzhou-Chengdu-Chongqing buried natural gas pipeline, a three-dimensional dynamic finite element calculation model including pipeline, rock, soil, natural gas and explosives is established. Based on the veracity of the model, the influence of pipe diameter, wall thickness and buried depth of buried natural gas pipeline under blasting vibration on the characteristics of pipeline and surface vibration and the Von-Mises stress of pipeline are analyzed. According to the location relationship between pipeline and tunnel, the 3D dynamic finite element numerical model established by engineering geology and blasting condition can simulate the vibration state of pipeline and its surface. The simulated seismic waveform has a high similarity with the measured seismic wave at the corresponding position, and the relative error between the calculated value of vibration intensity and the measured value is less than 11%. When the tunnel depth is 41.5 m and the equivalent charge of tunnel blasting is 25kg, the vertical vibration velocity of the rock mass decreases with the increase of the distance between the rock mass and the detonation source, and the further away from the detonation source, the slower the attenuation is. The vibration velocity at the interface of the rock and soil over the explosion source attenuates to about 3cm/s, and there are two extremum points in the vicinity of the pipeline and on the surface of the soil respectively. Through further analysis of the dynamic response of pipeline and soil with different pipe diameter, wall thickness and buried depth, it is found that the peak vibration velocity of pipe particle decreases with the increase of pipe wall thickness, while the vibration velocity of surface soil is basically unchanged. With the increase of peak particle velocity, the surface vibration velocity also decreases. The ratio of pipe diameter to wall thickness under the same pressure has a great effect on the Von-Mises stress of the pipeline, but the influence of the buried depth of the pipeline is almost no; the buried depth of the pipeline increases. The peak vibration velocity of the pipe particle decreases, but the vibration velocity of the topsoil over the pipeline increases.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE973

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