城市桥梁拆除爆破塌落振动对市政管线的损伤机理和安全判据研究

City bridge demolition blasting demolition method for security, time limit for a project, and has obvious advantages in environmental impact, etc and get more use. City under the bridge, however, water, electricity, gas and other kinds of shallow buried pipelines vertical and horizontal distribution, and distribution of subway tunnels, civil air defense works and having culverts and other municipal facilities. Therefore, needs to carry out the city bridge blasting collapsing vibration damage mechanism of municipal pipelines and safety criterion research, to ensure the blasting safety. This topic proposed the use of theoretical analysis, scale simulation and prototype test, numerical calculation and engineering application of the combination of research methods, and application based on wavelet packet transform Blasting demolition method get more use for security, time limit for a project, and has obvious advantages in environmental impact, etc in city bridge demolition. However, under the city bridge, water, electricity, gas and other kinds of shallow buried pipelines vertical and horizontal distribution, and possible distribution subway tunnels, civil air defense works and having culverts and other municipal facilities. Therefore, we need to carry out the research on damage mechanism and safety criterion of municipal pipelines in City Bridge blasting collapsing vibration to ensure the blasting safety. This topic proposed to use the combination methods of theoretical analysis, scale simulation and prototype test, numerical calculation and engineering application, and application the vibration signal analysis methods based on increased wavelet packet transform, establish a nonlinear viscoelastic model which characterization nature relationship of the bridge and all kinds of municipal pipeline. Finally the dynamic response characteristics and damage mechanism based on the collapsing vibration of city bridge demolition blasting to municipal pipeline can be got, the comprehensive safety criterion which can include the three elements of the blasting seismic wave (amplitude, frequency and duration) and energy distribution characteristics. Research results has theoretical guidance meaning and value of engineering application in the city bridge engineering of blasting demolition under complicated environment to ensure that all kinds of municipal pipeline safety, and has reference value as well as all kinds of blasting demolition in the city towering buildings.

城市桥梁拆除中爆破拆除法因在安全、工期和环境影响等方面具有明显优势而得到更多利用。但是，城市桥梁下方水、电、气等各类浅埋管线纵横分布，且可能分布地铁隧道、人防工事和排洪涵洞等市政设施。因此，亟需开展城市桥梁爆破塌落振动对市政管线的损伤机理及安全判据研究，确保爆破安全。本课题拟运用理论分析、缩尺模拟和原型试验、数值计算与工程应用相结合的研究方法，以及应用基于改进提升小波包变换的地震波信号分析方法，建立表征桥体、各类市政管线间本质关系的非线性粘弹塑模型。最终得到城市桥梁爆破塌落冲击荷载作用下各类市政管线结构的动力响应特性和损伤机理，以及能够同时考虑市政管线结构特性、塌落振动地震波三要素(振幅、频率和持续时间)及能量分布特征的综合安全判据。研究成果不仅对复杂环境下城市桥梁爆破拆除工程确保各类市政管线安全具有理论指导意义和工程应用价值，同时对城市各类高耸建筑物爆破拆除工程也具有借鉴和参考价值。

油气管道以及各类市政管道在保障居民生活的同时，也面临着诸多外部载荷破坏的风险，其中塌落冲击载荷就是一种极具危害效应的外部载荷，尤其是城市内的高层建筑在受到攻击或者进行拆除的塌落振动会对各类市政管线造成十分严重的影响。因此研究高架桥等建（构）筑物塌落冲击对地下浅埋管线的影响，对于管道的敷设、防护，以及爆破拆除工程的设计和爆破危害效应的防护都具有现实意义。课题对塌落冲击载荷作用下埋地管道的动态响应和冲击相似律进行了深入研究。主要取得以下研究成果和结论：.（1）有关塌落冲击埋地管道动态响应理论，基于Kelvin粘弹性模型，并进一步发展Kelvin粘弹性模型作为地基模型，研究了塌落冲击载荷作用下埋地管道动态响应，在此基础上分析了埋地管道的受力和振动，推导出了埋地管道受到冲击作用后的沉降表达式、竖向和水平位移表达式、位移以及速度响应公式。.（2）选取影响埋地管道动力响应的三个主要因素：重物质量、塌落高度和管土刚度比进行了试验探究。.（3）结合爆破拆除工程针对高架桥塌落振动相似模型进行了理论推导和数值模拟研究。.（4）在不考虑应变率效应时，依据π定理，推导得到了不考虑应变率效应的冲击相似律，整个冲击过程中各个因子是完全符合相似关系，其相似关系是完全自恰的。而在引入应变率效应时，原有的相似律发生畸变，不存在精确符合原型的相似关系，进而从理论上证明了在高应变率条件下，模型试验结果是不可能完美、精确地适用于原型试验，其误差只能在尽可能减小而不能消除。为减弱应变率效应，提出了基于调整初速度的相似律修正方法，使得修正后的相似律可以更加准确地映射至原型，设计了落锤跌落冲击管道的试验并进行了数值模拟研究。通过对三组试验中管道挠曲变形和测点应变量的分析得到：修正后的模型试验不论是在挠曲变形还是应变情况都与原型试验更加接近。其中挠曲变形方面，修正后的模型相比未修正的模型误差减小了50%以上，而塑形应变量的误差减小了83%。