基于希尔伯特损伤特征向量的挡土墙结构损伤诊断

Damage diagnosis of retaining wall structures based on the Hilbert damage feature vector

为了诊断挡墙结构损伤,通过希尔伯特-黄变换对激励作用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,筛选出对损伤较为敏感的特征频段,基于特征频段创建希尔伯特损伤特征向量,并提出损伤识别指标:能量比变异系数。基于损伤特征向量及损伤指标,提出了一种用于挡墙结构的损伤诊断方法,即通过损伤特征向量判别挡墙损伤状态,通过损伤指标走势曲面图诊断挡墙损伤位置,通过损伤指标与损伤程度间的定量关系识别挡墙损伤程度。对某桩板式挡墙进行了动力测试,验证该损伤诊断方法的可行性及有效性。结果表明:当挡土墙无损(无钻孔)时,损伤特征向量为零向量;当挡土墙有损(有钻孔)时,损伤特征向量为非零向量。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。建立了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。该损伤诊断方法可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。

To diagnose damages within a retaining wall structure,the Hilbert marginal energy spectrum analysis was performed via the Hilbert-Huang Transform of a virtual impulse response function of responses to the retaining wall under excitations.The feature frequency bands,which were much more sensitive to damage,were selected.The Hilbert damage feature vector was established via the feature bands.Then,a damage identification index(energy ratio variation coefficient)was proposed.Based on the damage feature vector and damage index,a damage diagnosis method for retaining wall structures was proposed.The damage state of the wall could be detected via the damage feature vector,damage location of the wall could be diagnosed via the trend surface of damage index,and damage intensity of the wall could be identified via the quantitative relationship between the damage index and damage intensity.Dynamic tests on a pile plate retaining wall were done to verify the feasibility and validity of this damage diagnosis method.Test results show that the damage feature vector is a zero vector when the retaining wall is undamaged(no drilled holes)while that is a non-zero vector when the retaining wall is damaged(drilled holes).The damage state of the wall can be detected via the damage feature vector.The partial damage causes greater fluctuation of trend surface of damage index.The damage location of the wall can be detected via the coordinate of peak value in the trend surface.The quantitative relationship formula between the damage index and damage intensity is established.The damage intensity of the wall can be calculated reversely when the damage index is available.Thus,the damage state of the wall can be detected sensitively,damage location of the wall can be diagnosed validly,and damage intensity of the wall can be identified quantitatively via this damage diagnosis method.