【作者】 徐慧峰；

【导师】 邱静；

【作者基本信息】 国防科学技术大学 ， 机械工程， 2010， 博士

【摘要】 水平导向钻是当前非开挖市政建设的主要设备之一。由于其施工过程是“不可见”的,必须准确探测施工区附近的地下管线,否则会带来很大的施工风险。本文针对当前地下管线探测方法在规避施工风险方面存在的问题,在国家电网公司重大基础研究项目的资助下,应用弹性波探测原理,开展地下管线水平导向钻随钻探测理论与技术的研究,通过在钻头处安装探测设备,随钻同步探测施工轨迹附近的掩埋管线或障碍物的分布状况,这对促进水平导向钻安全施工和城市地下管线的规范化管理具有重要意义。本文主要研究工作及结论如下:1、分析当前城市地下管线探测技术的现状及不足,结合水平导向钻施工工艺和管线探测工艺,应用弹性波探测原理,提出了基于弹性波的水平导向钻随钻探测方案。2、根据随钻探测的环境条件和工作特点,建立了随钻探测土介质中有限时长力源边界激发的弹性波圆柱散射模型,并针对其特殊边界条件造成的求解困难,采用波函数展开法和Graf加法定理,分析求解单根管线探测目标弹性波的分布模式和传播规律。研究发现,在径向力源激励和近距离探测条件下,接收信号中纵波和横波并存,信号幅值受土介质与目标管线的阻抗匹配程度、目标管线几何参数等的制约。研究结果为开展随钻弹性波探测提供了理论依据。3、针对地下现存管线分布复杂、类型很多,探测系统数学模型难以得到解析解的问题,采用有限元方法建立了地下管线随钻探测系统的有限时长力源激发的弹性波散射数值分析模型。从弹性波传播特性和接收信号特征两个方面对其进行了正演分析,明确了弹性波能量场分布的方向性、复杂管线条件下弹性波的传播特征及接收信号的频谱特性。研究结果对随钻探测系统探测能力分析及探测信号的分析判读具有重要的指导意义。4、针对探测波场接收信号易混叠而采用求解系统脉冲响应序列提高判读性所带来的病态特征问题,研究了对病态问题的规整化解决方法—L1模解卷积方法和基于粒子群优化的Bayes解卷积方法,比较了两种方法解算效果以及计算效率,结果表明两种方法宜结合使用,互补地应用于探测系统的在线解算和离线分析。同时,针对随钻探测弹性波圆周扫描探测的特点,提出了时延补偿聚焦成像技术,提高了管线探测系统对探测目标的判读能力。5、根据随钻探测工作环境决定的系统结构设计要求,以及系统小型化、实时性的要求,设计和开发了水平导向钻随钻弹性波探测试验系统,并进行了工程试验测试。通过试验,验证了本文提出的理论分析模型、探测信号分析及成像算法的正确性和可行性,同时也表明了所研制的试验系统能有效探测水平导向钻施工路径附近近距离管线以及其它障碍物。总之,本文针对水平导向钻规避施工风险的问题,基于弹性波理论,提出了一种新颖的地下管线随钻探测方法。对其探测原理进行了深入分析,归纳总结了随钻探测弹性波传播规律,提出了适用于随钻探测系统的信号解卷积方法和探测波场成像技术,并设计开发了一套水平导向钻随钻探测试验系统。基于弹性波的地下管线水平导向钻随钻探测是一项具有挑战性的值得研究的创新技术,具有重要的技术推广和工程实际应用价值。更多还原

【Abstract】 Horizontal directional drilling (HDD) is one of the most widely-used trenchless technologies in municipal infrastructure construction. In HDD process, it is of great importance to detect the pipelines buried around the drilling tracks correctly while drilling. Otherwise, the drilling process may suffer very high risk. However, there exist some deficiencies in current underground pipelines detection methods and equipments, and hazard accidents are hardly avoided in HDD construction.In this thesis, funded by the Key Development Program for Basic Research of STATE GRID Corporation of China, a novel solution to the online detection while drilling based on elastic wave propagation principles is proposed, and an experimental system is developed and tested. The main work can be summarized as:1. The current underground pipelines detection methods and equipments are systematically reviewed. This tells the fact that almost all of these methods and equipments operate on ground surfaces and in the way of offline. Unlike the current systems, a novel online detection solution is firstly outlined based on elastic wave detection principles. The proposed design is desired to combine the detection process and drilling process of HDD together as a whole.2. Considering HDD operation modes, constrains and other assumptions, a cylindrical elastic wave scattering model under linear limited width pulse boundary excitation is established. The model is then solved by using the combination of wave function expansion and Graf addition theorem, in order to deal with the complicated boundary conditions. As a typical case, the elastic wave propagation pattern corresponding to a single underground pipeline is thoroughly analyzed. It is shown that, in the situation of radial power excitation for close target detection, the longitudinal waves are the major reflected waves, although there also exist reflected transverse waves and surface waves. The amplitude of received reflected waves is determined by many factors, mainly by the impedance matching between the target pipelines and the soil, and the geometry parameters of the target pipelines. These works provide a basic foundation for online target detection while HDD drilling.3. It is hard to get analytical solutions to the reflected waves in the situation that multiple pipelines are distributed complicatedly. To overcome this difficulty, a simulation model based on Finite Element Method (FEM) is established, the wave propagation disciplines and the characteristics of received signals are thoroughly studied using this model. The results provide foundation for detection area ascertaining and received signals interpretation.4. In the process of detection while drilling, the overlap of the received reflected signals from complicated objects causes difficulties in signals interpretation. In order to solve this problem, two deconvolution methods, L1 norm deconvolution and Bayes deconvolution based on particle swarm optimization, are investigated. These two deconvolution methods are compared using the indice of the resolution and the time of calculation. The results show that both methods have advantages and disadvantages, the Bayes deconvolution is more suitable for online calculating and the L1 norm deconvolution is more suitable for offline analysis. While the HDD is drilling slowly, the detection system is scanning in circle, this makes it possible to compensate and enhance the target wave image on the ground terminal using the information from multiple cycles, thus, an elastic wave imaging method based on time delay compensation is proposed, and this has improved the resolution of the wave image of the underground targets.5. An experimental HDD online detection system is developed. Some demonstration experiments are implemented on HDD testing and training sites, as well as in practical construction projects. The results show that the proposed design and the theoretical analysis are reasonable, the detection and imaging techniques are effective, and the experimental system shows desired performance in detecting underground pipelines closely around the drilling tracks within one meter.In summary, the thesis has proposed a novel solution to the online detection while drilling based on elastic wave propagation principles, developed and tested an experimental system. The solution and system developed can reduce the risk for HDD construction process.更多还原