Prediction of the earthquake-induced permanent displacements of retaining structures represents a key step in the context of a performance-based design approach. For retaining walls with shallow foundations, this issue is usually dealt with using the well-known Newmark sliding-block method. However, several studies have shown that this method is unsuitable to provide a trustworthy prediction of the displacements experienced by the embedded cantilever retaining walls under seismic loading. To overcome this drawback, a method of practical interest is proposed in the present study for a prediction of the earthquake-induced permanent displacement of these structures. In such a method, the rotation and the associated displacement of the structure are evaluated solving a simple equation of motion when the ground acceleration exceeds a critical value. Unlike Newmark’s method, this critical value is updated during the seismic event by calculating the forces acting on the wall by a closed-form solution recently derived by the authors. To assess the predictive capability of the present method, some comparisons with well-documented case studies available in the literature are shown. The method is also simple to use and requires few conventional parameters as input data.

Compared with Fast Fourier Transform, Wavelet Transform and other methods, the Hilbert-Huang Transform (HHT) method is more suitable for non-stationary signals, which can be used to denoise seismic signals and accurately extract the local instantaneous characteristics of the signals. Currently, the HHT method has been widely recognized in the field of civil engineering structural damage identification. In this paper, the HHT method was introduced into the identification of failure mode of slope soil under ground motion. To verify the feasibility of the proposed approach, large-scale shaking table tests were conducted. The results show that the proposed method is in good agreement with the sliding surface observed in the shaking table test. The dynamic response characteristics of the slope based on the variation in the MSA are consistent with the test results. Moreover, the seismic damage mechanism differences of gravity retaining wall, sheet pile wall and anchored sheet pile wall reinforced slope were discussed. The results provide technical reference for the reasonable protection of slope engineering in seismic zones.

Many facilities, including port facilities, were damaged by a major earthquake that occurred almost 100 years ago (the Great Kanto Earthquake of 1923). At the Port of Yokohama, the block-type quay walls of the reclamation site at sea were almost completely destroyed. However, historical facts remain that some quays have escaped damage. The authors attempted to determine the factors that caused this difference using current model testing techniques. Centrifuge model tests simulating the quay walls at the site were performed to reproduce the damage caused by the earthquake. The foundation ground of the quay wall that did not collapse consisted of soft alluvium with a rubble mound. The presence or absence of a collapse was considered to be caused by differences in the foundation, and the shaking table tests were implemented under different foundation conditions. Consequently, the events that occurred at the site were successfully reproduced.

The road network is the primary infrastructure for reaching earthquake-affected areas and bringing the necessary aid. Damage to components of the roadway network (for example, earth retaining structures) can have a significant impact on the movement of people and goods both during an emergency and in the long-term period. During past and recent earthquakes worldwide, several retaining structure failures were caused by the seismic action. In Italy, many earth-retaining walls are located in regions characterized by high seismic hazard. Therefore, the vulnerability assessment of these structures is of paramount importance for performing seismic risk analysis of the road network. Fragility curves represent a useful tool for estimating the seismic vulnerability of these typological structures. Novel sets of fragility functions for cantilever retaining structures, the most common earth retaining structures along the Italian roadway network, were built in this study using a numerical approach. Advanced simulations were carried out using real accelerograms as seismic input and adopting the usual T-shape structure and horizontal backfill configuration as models. Special effort was spent to identify the Intensity Measures (IMs) best correlated to the response of the object walls. To conclude, the proposed fragility curves can be effectively adopted for rapid assessment of earthquake-induced damage both during emergency management to provide the safest ways and also in the preparedness phase to identify proper countermeasures for seismic risk mitigation.

Cellular quay wall structures, which are relatively economical deep-water harbour structures, have been used in marine harbours. In deep-water cellular quay walls, backfilled stones have been used behind the cells to improve the stability and seismic resistance of cells, which are steel cylinders filled with soil, by reducing the earth pressure behind the cells. However, it is believed that by solidifying the ground behind the cells, earth pressure is reduced, and the cells become more seismically resistant than if rubble stones have been installed. In this study, shaking model tests were conducted using a centrifuge to investigate the seismic behaviour of a cellular quay wall with a solidification method behind it. In the tests, a cell was modelled as a rectangular shape to observe the ground deformation inside the cell and the natural period of the cell was made close to that of the cylindrical body. The shaking model tests showed that the cement-treated soil cracked locally; however, the displacement of the quay wall in front of it was reduced compared to that of the unimproved quay wall, confirming the effectiveness of the solidification method. It was also found that the block- and grid-type improvements resulted in similar levels of quay wall displacement, indicating the possibility of reducing the improvement ratio of the solidification method.

Ports and coastal areas rely on coastal protection schemes both for normal operation, as well as for protection against extreme events, such as storm surges and Tsunamis. The failure of many protection structures, particularly massive caisson-type breakwaters during the 2011 Tohoku earthquake and Tsunami provoked intensive efforts to understand how such believed to be robust systems could have failed, and how their performance could be improved. Although sliding and uplifting were often proposed as key failure mechanisms, observations from more recent physical model studies raised the possibility of scour–induced geotechnical failure within the soil, before sliding could take place. The effect of such scouring on geotechnical bearing capacity was captured though a scour-dependent combined failure surface, derived using simple finite element models based on scour geometry, directly captured from the experiments. Expanding on this concept, the same “hybrid” modelling technique also reveals the role of second order effects, due to significant pre-failure rotation due to scour, which increases the horizontal force acting on the foundation. Combined with a sliding soil-foundation interface and appropriate combined (Tsunami) loading, a complex combined sliding/geotechnical failure mechanism can be induced, mimicking the ones experimentally observed. Such a combined mechanism reproduces the reduction of sliding resistance, which has been observed in large scale hydraulic experiments (attributed to a reduction of an “apparent” interface friction coefficient).

A rigid nonvertical retaining wall with horizontal backfill is subjected to a seismic load following a pseudo-static approach considering a uniform surcharge. The theoretical analysis is conducted by considering a more realistic logarithmic spiral failure surface following a limit equilibrium-based approach. Generalized formulations are established to calculate the active earth pressure expressed in terms of normalized coefficients. The effect of cohesion and internal angle of friction on the active earth pressure has also been studied and observed to decrease the active earth pressure thus reducing the dimensions of the wall. The parametric study is conducted to understand the variation of the earth pressure. The point of application of the total active thrust is also determined considering the seismic effect. The results obtained from the analysis for the active earth pressure were found to be in good agreement with the previous studies and was observed that the results of height of application of total active thrust obtained were higher in comparison to the existing literature.

Earth retaining structures are geo-structures designed and constructed to encounter the lateral thrust imparted by backfill soil. Stability assessments of earth retaining structures in the past were performed by accounting homogenous backfill soil due to the ease of Factor of Safety (FoS) determination against a particular failure mode. This deterministic stability assessment dismisses the impacts of spatial soil property variability, thus presenting a restricted interpretation of reality. For in-situ soils, these spatial variations are attributed from inherent variability whereas for relocated backfill geo-materials, nonuniformity in layering and compaction are the main sources invoking variability in soil properties. The complexities due to aforementioned variabilities proliferate extensively under seismic loading conditions. The uncertainties associated with such soil property variability need to be comprehended for attaining a reliable seismic stability assessment of retaining walls. This present study probabilistically explores the implications of geo-material property variability on the sliding stability assessment of a gravity wall subjected to both static as well as pseudo-static loadings. The variability accounted in this study encompasses dry unit weight and friction angle of backfill soil as well as interface friction between wall base and foundation soil. The aforementioned analysis has been performed with the aid of SLOPE/W module of GeoStudio software through limit equilibrium slice approach i.e., Morgenstern-Price method, due to its robustness in accounting both interslice normal as well as shear forces. A parametric assessment has also been performed by altering the statistical parameters of the above-mentioned soil properties, thereby delineating its impact on the sliding stability of gravity wall along with probability of failure and reliability index. This study depicted that accountancy of uncertainties is crucial to obtain reliable stability assessment of gravity wall, which has been attained through the application of probabilistic method in comparison to conventional deterministic approach.

This paper investigates the seismic response of a large diameter pile-supported wharf located at the port of Gioia Tauro, in Southern Italy. To capture the non-linear behavior of both the liquefiable ground and the superstructure, fully coupled 2D nonlinear dynamic analyses were conducted with FLAC2D. The cyclic response of the liquefiable soils was modelled using the PM4Sand, while the nonlinear behavior of the piles was accounted for by means of a lumped plasticity model. Hazard-compatible ground motion records were used as input excitations for three different return periods, and two different geotechnical models were developed to capture variable site conditions. The first model represents the native soil deposit, which is comprised of medium to dense coarse-grained soils, while the second model considers the presence of a significantly looser fill that was found in certain areas of the port. Specific attention was given to the estimation of moment and ductility demands on the piles. The sliding mechanism of the submerged slope showed significant variations with ground motion intensity, which in turn yielded different load-transfer patterns on the piles. For long return periods, the in-phase occurrence of kinematic and inertial effects is shown to be more likely at the pile-deck connections, where the kinematic loads are predominant and aggravated by inertial effects during the early stages of ground shaking. Final remarks are given for future studies regarding the assessment of kinematic and inertial effects in pile-supported wharves.