基于在役列车车载加速度计响应信号盾构隧道损伤识别机理研究

Rail Transit System is a traffic lifeline of a city. It's crucial for the health service of the shield tunnel structure on the safe operation of the city. The damage identification of tunnel structure (lining cracking, bolt loosening, concrete deterioration and soil erosion after lining of tunnel) is a key technology in structural health monitoring system. However, it's very difficult to identify damages on the tunnel structure due to significant non-linear characteristics of tunnel structure and hardly measured excitation and unpredictable interaction between soil and structure. In this study, we propose a method to identify the tunnel structure damages based on the vehicle-mounted accelerometer of the service train, in which the distribution of structure stiffness of the tunnel can be continuously measured. Firstly, the spring vehicle-track-tunnel-soil coupling model is established to analyze the vehicle response by change of stiffness of the track and tunnel. Then, the dynamic response signals of each part are analyzed before and after damages, and the sensitive feature parameters of local damage are extracted. Finally, those influence factors including the speed and shaft load of vehicle, accelerometer layout optimization effect are analyzed and the statistical damage identification index and the relationship between vehicle speed and target accuracy are built to realize damage location ultimately. Therefrom, an innovative sensing method and mechanism of structural damage detection for urban metro shield tunnel might be established and the technical bottleneck of shield tunnel health monitoring system should be broken through. The solution of this problem will provide a key technical guarantee for the safety of metro operation in China.

轨道交通作为城市的交通命脉，其盾构隧道结构的健康服役对于城市正常运转至关重要。隧道结构损伤（衬砌开裂、螺栓松动、混凝土劣化、壁后水土流失）识别是结构健康监测系统中的一项关键技术，但由于隧道结构存在显著的非线性特征、激励难测以及土-结构相互作用，导致隧道结构损伤难以识别。本研究提出基于服役列车车载加速度计信号响应隧道结构损伤识别方法，通过连续测量隧道结构的刚度变化开展研究。首先，建立弹簧车辆-轨道-隧道土体耦合模型，分析轨道刚度及隧道刚度变化的振动响应；然后，分析各区间损伤前后的动力响应信号，提取局部损伤敏感特征参量；最后分析服役车辆运行速度、车辆轴负载、加速度计布设优化影响，并构建基于统计的损伤识别指标，建立车速与目标精度关系，实现损伤定位。以期建立起城市地铁盾构隧道结构损伤定位感知机理与新方法，突破盾构隧道健康监测系统发展的技术瓶颈，该问题的解决将为我国城市轨交运营安全提供关键技术保障。

轨道交通作为城市的交通命脉，其盾构隧道结构的健康服役对于城市正常运转至关重要。然而地铁隧道由于服役时间长，初始施工缺陷如错台、掉块等，在环境因素与列车循环荷载作用下进一步恶化，导致严重的渗漏水、不均匀沉降等病害，可能会导致严重的事故。因此，识别和定位隧道结构的病害与损伤，实时的监测隧道的健康状态，对维护地铁隧道长期安全运营具有重要的现实意义。现有地铁结构监测依赖于固定点位传感器，通常只能覆盖地铁隧道的部分重点保护区段，并且成本高昂，本项目致力于研究一种高效的、经济的、全域的隧道结构健康监测方法。.本研究通过安装在服役列车上的振动传感器，采集列车行驶时的振动响应信号，分析隧道损伤前后列车振动响应，提出基于服役列车车载加速度计信号响应隧道结构损伤识别方法，通过连续测量隧道结构的刚度变化开展研究。首先，建立弹簧车辆-轨道-隧道土体耦合模型，分析轨道刚度及隧道刚度变化的振动响应；然后，分析各区间损伤前后的动力响应信号，提取局部损伤敏感特征参量；最后分析服役车辆运行速度、车辆轴负载、加速度计布设优化影响，并设计制作了车隧耦合振动的缩尺比例试验模型，验证了上了基于车载加速计损伤识别方法的可行性。.取得的重要成果包括：1）建立了双层梁式车隧耦合振动模型，考虑线弹性轮轨接触时采用动轮单元法求解，考虑非线轮轨接触时采用交叉迭代法求解；2）提出基于车载加速度计识别隧道结构损伤的两类算法即基于小波包能量的损伤识别算法与基于谱峭度的损伤识别算法，分别构建了小波包能量累积和和谱峭度面积变化率两个核心指标，并给出两类算法对应的核心指标与的计算流程图；3）利用VI-Rail与ANSYS联合仿真建立了三维车隧耦合振动的数值模型，并基于该模型验证所提的两类损伤识别算法的可行性。.项目以期建立起城市地铁盾构隧道结构损伤定位感知机理与新方法，突破盾构隧道健康监测系统发展的技术瓶颈，该问题的解决将为我国城市轨交运营安全提供关键技术保障。