Damage Identification Investigation of Retaining Wall Structures Based on a Virtual Impulse Response Function

Abstract

To eliminate the influence of excitation on the wavelet packet frequency band energy spectrum (ES), ES is acquired via wavelet packet decomposition of a virtual impulse response function. Based on ES, a character frequency band vector spectrum and damage eigenvector spectrum (DES) are created. Additionally, two damage identification indexes, the energy ratio standard deviation and energy ratio variation coefficient, are proposed. Based on the damage index, an updated damage identification method for retaining wall structures is advanced. The damage state of a retaining wall can be diagnosed through DES, the damage location can be detected through the damage index trend surface, and the damage intensity can be identified by establishing a quantitative relationship between the damage intensity and damage index. To verify the feasibility and validity of this damage identification method, a vibration test on a pile plate retaining wall is performed. Test results demonstrate that it can distinguish whether the retaining wall is damaged, and the location of partial damage within the retaining wall can be easily detected; in addition, the damage intensity of the wall can also be identified validly. Consequently, this damage identification theory and method may be used to identify damage within retaining wall structures.

Investigation of Damage Diagnosis of Retaining Wall Structures Based on the Hilbert Damage Feature Vector Spectrum

“…e additional dynamic effects of the filled soil on the wall can be neglected under low strain excitations. us, the filled soil and retaining wall can be regarded as one structure [1]. And the damage identification method is not influenced by the filled soil.…”

“…ese damages might cause collapse or failure of the wall, if these damages were not found in time and repaired efficiently. Once these retaining walls, such walls with high danger and significance as pile plate retaining walls used to support deep ditch, under consistent walls used to support under structures, and walls used in high slopes, collapsed, major accidents might occur, as shown in Table 1 and Figure 1 [1]. From Table 1, collapse of the walls was mainly caused by the rainfall, construction quality faults, and damages.…”

Investigation of Stability Alarming for Retaining Wall Structures with Damage

“…Under low strain excitation, it is assumed that both the normal pressure and tangential friction can be replaced with those under static equilibrium [23]. In addition, it is also assumed that the backfill is compressed greatly and that the backfill behind the retaining wall vibrates together with the wall under low strain excitation [24]. Thus, the earth pressure can be equivalent to a series of normal spring element components, and the friction can be equivalent to a series tangential spring element component [25].…”

Mode identification by eigensystem realization algorithm through virtual frequency response function

“…It is obvious that ERA with data correlations and NExT‐ERA both use the data correlation to generate the impulse responses. Xu proposed a virtual impulse response function for damage identification of retaining wall structures, which was not the complete structural impulse response. In many methods, the impulse responses are obtained by the assumption of white and stationary noise excitation.…”