Gravity retaining wall with geogrids has showed excellent seismic performance from Wenchuan great earthquake. However, seismic damage mechanism of this kind of wall is not sufficiently clear. In view of this, a large shaking table test of the gravity retaining wall with geogrids to reinforce the subgrade slope was carried out, and based on the Hilbert-Huang transform and the marginal spectrum theory, the energy identification method of the slope dynamic failure mode was studied. The results show that the geogrids can effectively reduce displacement and rotation of the retaining wall, and it can effectively absorb the energy of the ground movement when combined with the surrounding soil. In addition, it also reveals the failure development of the gravity retaining wall with geogrids to reinforce the subgrade slope. The damage started in the deep zone near the geogrids, and then gradually extended to the surface of the subgrade slope and other zones, finally formed a continuous failure surface along the geogrids. The analysis results of the failure mode identified by the Hilbert marginal spectrum are in good consistency with the experimental results, which prove that the Hilbert marginal spectrum can be applied to obtain the seismic damage mechanism of slope.
To understand the mechanism of the earth structure damage, a wide range of investigations along roads in seismic hazard areas
have been carried out after the 2008 Wenchuan earthquake. In this paper, the results from 41 roads investigated are presented,
and the 41 roads are located in 7–11 intensity zones and consist of rural/county roads, province roads and state roads in
Sichuan province. According to the investigation, the types of damaged slopes and retaining walls are classified and statistical
analyses are performed. In the statistical analyses, various impact factors to seismic slope and retaining wall damage were
studied, such as slope inclination, height of slope and retaining wall, site conditions, and seismic intensity. In addition,
some relationships were developed, including the quantity of damaged slopes with slope inclination and height, the angle between
route and fault rupture directions, and site conditions. Finally, some reasonable suggestions are put forward on the designs
and constructions of slopes and retaining walls when they are subject to seismic activity. 相似文献
To estimate the near-fault inelastic response spectra, the accuracy of six existing strength reduction factors (R) proposed by different investigators were evaluated by using a suite of near-fault earthquake records with directivity-induced pulses. In the evaluation, the force-deformation relationship is modelled by elastic-perfectly plastic, bilinear and stiffness degrading models, and two site conditions, rock and soil, are considered. The R-value ratio (ratio of the R value obtained from the existing R-expressions (or the R-μ-T relationships) to that from inelastic analyses) is used as a measurement parameter. Results show that the R-expressions proposed by Ordaz & Perez-Rocha are the most suitable for near-fault ground motions, followed by the Newmark & Hall and the Berrill et al. relationships. Based on an analysis using the near-fault ground motion dataset, new expressions of R that consider the effects of site conditions are presented and verifi ed. 相似文献