预应力波纹管孔道压浆质量的超声检测方法研究

The corrugated pipe grouting is one of the key working procedure in the post-tensioned pre-stressing concrete beam, the grouting quality （compactedness, defect）directly affect the bridge durability, carrying capacity and crack resistance, but there is still no reliable test method nowadays.The aim of this project is to study the ultransonic detect method of the prestressed bellows structure from theory and experiment comprehensively. By strict wave theory, the guided wave propagation in the steel strand and the transient waveform of the multi-layer cylindrical structure will be calculated; the finite element or finite difference method will be used to simulate the waveform . By using the physical model of discrete slice, the model 2 d sound field will be measured, and array detection signal will be collected. Based on the theoretical calculation and finite element (difference) simulation and model 2d signal characteristics, by means of the signal processing, the signal pattern recognition and feature extraction will be performed to obtain the obvious defect information.On the basis of conclusion obtained by theory and physical model experiment, the discrete models are set up to measure signal ,the separation weak signal will be enhanced treatment to obtain an instructions function which could calibrate grouting quality. Finally the actual production of various reserve defect of the discrete model will be fabricated to verify the correctness and accuracy of the instruction fuction, the research can provide a solid foundation for a practical engineering testing instruments research and development.

波纹管孔道压浆是后张预应力梁最关键工序之一，其压浆质量（密实度、缺陷）直接影响着桥梁的耐久性、承载能力和抗裂性能，但目前还没有可靠的检测方法。本项目将从理论及实验上对预应力孔道波纹管结构的超声检测方法进行全面研究。由严格的波动理论出发，计算钢绞线中的导波传播规律及多层圆柱结构的瞬态波形，利用有限元或有限差分方法对波纹管结构进行建模及仿真，获取仿真波形。建立多种离散物理切片模型，对模型进行二维声场测量，并获取阵列检测信号。将理论计算、有限元（差分）仿真以及模型实验获得的信号进行对比分析，借助于信号处理手段对信号进行模式识别及特征提取，分离出明显反应缺陷信息的信号。在此基础上再建立实际离散模型模块并进行测量，对分离出的微弱信号进行特征增强处理后得到能标定压浆质量的指示函数。最后实际制作预留缺陷的模型并进行检测，验证所标定的指示函数的正确性及准确性，为实际工程检测仪器的研发奠定坚实的基础。

波纹管孔道压浆是后张预应力梁最关键工序之一，其压浆质量（密实度、缺陷）直接影响着桥梁的耐久性、承载能力和抗裂性能。本项目从理论、仿真、信号处理及实验方面对预应力孔道波纹管结构的超声检测方法进行比较全面研究。（1）理论上从基本的波动方程出发，建立了多层圆柱导波的频散方程，考虑固体为多孔介质，探讨了孔隙度对波速及衰减的影响。（2）仿真了声波在波纹管结构中的传播声场，采用了小波包、合成孔径、信息熵等方法对信号进行处理，得到了压浆密实度的信息特征。（3）在模型实验上，建立了多种切片物理模型，进行了二维声场测量，得到了孔洞对声场的影响。在实际测量实验方面，自制了大功率脉冲发生器及多路信号采集系统，对实际工件进行测量，对比理论有比较好的吻合。本课题所取得的成果，将为波纹管孔道压浆工程质量检测奠定了一定的基础，促进这一技术在实际生产应用中更加趋于成熟。