环境激励下挡土墙结构损伤诊断及稳定性预警方法研究

With the development of urbanization in our country, the failure or collapse of retaining structures, which are used widely, cause huge losses of life and property as well as infrastructures. The safety of retaining structures has been a significant issue which is urgently solved in urbanization. However, the investigation of damage diagnosis and safety alarming for retaining structures is still in its infancy. In view of this, the retaining wall structures which as one type of retaining structures are studied in this project. An analysis dynamic model of the wall-soil system dynamic test problem is established. Based on the condition space theory, the establishment and solution to the condition equation to the wall-soil dynamic test model are performed. Though numerical calculating, model experiments, field tests, signal analysis, and system intelligence identification, the Hilbert marginal energy spectrum analysis of the virtual impulse response function of dynamic responses to the retaining wall structures under ambient excitations is performed. The damage feature vector spectrum and damage identification indexes, which can be used to identify damage, are created. A damage diagnosis method for retaining wall structures is proposed in order to sensitively distinguish the damage state of the wall, validly diagnose the damage location and quantitatively identify the damage intensity of the retaining wall. Then the relationship between the damage index and stability of the retaining wall is analyzed under different damage conditions, and a stability alarming method for the retaining wall structures is proposed. The stability state of retaining wall structures can be alarmed by the damage indexes under different damage conditions.

随着我国城镇化建设的推进，广泛使用的支挡结构失效或破坏，给人民群众的生命财产及国家的基础设施造成了巨大损失，其安全性已成为城镇发展亟待解决的重大问题，而关于支挡结构的损伤诊断及安全预警研究尚处于起步阶段。鉴于此，本项目以挡土墙这类支挡结构为研究对象，建立工作状态下墙-土系统动力测试问题的分析动力学模型，基于状态空间理论完成墙-土系统动测模型状态方程的建立及求解。通过数值计算、模型试验和现场测试，利用信号分析及系统智能识别等手段，对环境激励下挡墙结构动力响应间虚拟脉冲响应函数进行希尔伯特边际能量谱分析，创建反映挡墙损伤的损伤特征向量谱及损伤识别指标，拟提出一种用于挡墙结构的损伤诊断方法，实现敏感判别挡墙损伤状态、有效诊断损伤位置及定量识别损伤程度。分析不同损伤状态下损伤指标与挡墙稳定性间的关系，拟提出一种用于挡墙结构的稳定性预警方法，通过损伤指标对不同损伤状态下的挡墙稳定状态进行预警。

在役挡土墙结构在多因素作用下会出现损伤，而损伤可能降低其安全性。为了评价在役挡土墙结构的损伤及安全性，对环境激励下挡土墙结构动力响应间虚拟脉冲响应函数进行希尔伯特边际能量比谱分析，基于希尔伯特频段的损伤敏感性分析，筛选出对损伤较为敏感的特征频段，创建识别挡土墙结构损伤的希尔伯特损伤特征向量和损伤指标，提出一种用于挡墙结构的损伤诊断及安全性评价方法。即通过损伤特征向量判别挡墙损伤状态、损伤指标走势曲面图诊断挡墙损伤位置、损伤指标与损伤程度间的定量关系识别挡墙损伤程度、损伤指标与挡土墙稳定性间的关系评价其安全状态。为了验证该方法的有效性及可行性，对桩板式挡土墙进行了环境激励下的模型试验和现场测试。试验结果表明：当挡土墙无损时，损伤特征向量为零向量；当挡土墙有损时，损伤特征向量为非零向量。因此，通过损伤特征向量可判别挡墙损伤状态。局部损伤导致损伤指标走势图出现较大起伏，走势图峰值坐标即为局部损伤中心，通过损伤指标走势图的峰值特征可诊断挡土墙损伤位置。建立损伤指标与挡土墙损伤程度间的定量关系式，已知损伤指标可反算出损伤程度。随着损伤指标值持续增长，挡土墙稳定系数逐渐减小，挡土墙的安全性在逐渐降低。建立稳定系数与损伤指标间的定量关系可评价挡土墙的安全性。因此，该损方法可敏感判别挡墙损伤状态、有效诊断损伤位置、定量识别损伤程度以及评价安全性。