高桩码头结构动力损伤机理及其基于能量准则的整体安全性评估方法研究

There are a large number of old high-piled wharf in China. In order to ensure the safety of wharf, the effective means are badly needed to be used to detect them, assess its’ safety status, and provide the basis for repairment, reinforcement and reconstruction. In this project, around the high-piled wharf structure health monitoring, detection and safety evaluation, the numerical and physical model tests are used to reveal the inner laws of external environment、structural damage and dynamic characteristics of high-piled wharf. The variables and their combinations which are sensitive to dynamic signatures are studied. That can provide guidance for damage detection and recognition of high-piled wharf structure. The optimal layout of sensor can be achieved by research of the combination of the effective independence method and the MAC method. For the complex dynamic characteristic parameters of high-piled wharf structure, the stochastic subspace identification method and the frequency domain method are used to recognize them. Based on probabilistic sensitivity analysis, the identification method of damage of the high-piled wharf structure is proposed. Thus the diagnosis of damage location and damage degree of the high-piled wharf structure can be realized. The structure dynamic Benchmark correction models of the high-piled wharf is established according the test data of the environmental vibration and the Bias frame theory. On this basis, the overall safety assessment model is built according to the energy criterion. And the overall safety factor under various load combinations in the process of operation is analyzed. Finally, the overall safety assessment of the high-piled wharf is realized and the basis for repairment, reinforcement and reconstruction is provided.

我国存在大量的老旧高桩码头，为保证其安全，急需采用有效手段对其进行检测，评定其安全状况，并提供修复、加固与改造的依据。本项目围绕高桩码头结构的健康监测、检测与安全评估，用数值与物理模型试验的研究方法，揭示外部环境、结构损伤与动力特性之间的内在规律，研究对动力指纹较为敏感的变量及其组合，对高桩码头结构的损伤检测与识别提供指导；研究联合运用有效独立法和MAC法实现传感器的优化布置，针对高桩码头结构复杂的动力特性参数同时采用随机子空间法和频域法进行识别研究，提出基于概率灵敏度分析的高桩码头结构损伤识别方法，实现高桩码头结构损伤位置与损伤程度的诊断；基于环境振动测试和贝叶斯框架理论建立高桩码头结构动力基准Benchmark修正模型，在此基础上建立基于能量准则的高桩码头整体安全性评估模型，研究其在各种荷载组合工况下的整体安全系数，实现高桩码头结构的整体安全性评估，并为其加固改造提供依据。

老、旧高桩码头存在多种形式的结构损伤，给高桩码头的安全带来隐患。本项目系统开展高桩码头结构动力特性以及高桩码头结构健康诊断与评估技术的研究。首先，统计了高桩码头结构损伤样本，进行了高桩码头结构模型与现场试验，建立了高桩码头动力基准Benchmark模型，采用环境振动测试和贝叶斯框架理论确定结构参数最优值，以此模型研究分析了高桩码头的动力特性与损伤敏感性；其次，结合基于时域的随机子空间方法和频域方法的柔度差阵、应变模态、曲率模态等多种损伤指纹，构建了多维度高桩码头结构健康诊断综合技术。再者，运用有效独立法和MAC法，优化上部结构和桩结构中的初始测量点，提出优化传感器布置的分区遗传算法策略，从而高效获取高桩码头结构特性，并通过模型试验验证了该方法应用于高桩码头传感器优化布置的有效性。最后，结合概率分析方法考虑结构参数、土体参数以及外部荷载的随机性，提出码头结构宏、微观的性能指标，并从能量角度，采用变分原理和最小势能原理，提出基于能量准则的高桩码头结构安全性量化评估指标。从宏、微观与能量多角度完善了高桩码头整体的安全性评估方法，为高桩码头结构的安全状况评估，修复、加固与改造提供依据。