Quay Wall Research Articles

Investigation on behavior of anchored sheet pile quay wall improved by cement-soil: Centrifuge and numerical modelling

By using the centrifuge test and three-dimensional (3-D) finite element (FE) simulation with an advanced soil constitutive model, this study investigated the suitability and reinforcement effect of cement deep mixing (CDM) for stabilizing the anchored sheet pile quay (ASPQ) in soft clay. Besides, a parametric study was designed to analyse the influence of three factors, including the excavation depth ratio, the slenderness ratio and the strength of the CDM block, on the responses of quay wall and quay-surface settlement. The results showed that the effectiveness of CDM was closely related to its strength, slenderness ratio, and excavation depth ratio. There existed a critical slenderness ratio of the CDM block to minimize the lateral deflection of the quay wall. The influence of CDM block strength on the response of the quay wall was significant only when it had low rigidity. As a result of material improvement, the reduction in maximum wall displacement became more significant as the excavation depth ratio increased. A CDM block-to-excavation-strength shape factor was proposed to characterise the lateral response of quay walls in cement-improved soil.

Finite element analysis on dynamic behavior of sheet pile quay wall dredged and improved seaside subsoil using cement deep mixing

Sheet pile wall structures are commonly applied in coastal projects, particularly for the quay wall. This structural type normally is used in places where the ground has a low bearing capacity and is easily penetrable. Many sheet pile quay walls constructed in the past had low front water depth and did not satisfy the requirements of current standards. This issue could be addressed by improving the ground in front of the wall using cement deep mixing (CDM) and then excavating to increase the water depth in front of the wall. This paper numerically evaluated the dynamic behavior of the sheet pile wall after renovation. The numerical model was performed based on the finite element method (FEM) using the PLAXIS 2D program. The study focused on investigating typical parameters of the quay wall improved using the CDM, such as bending moment and displacement of sheet pile and the development of excess pore water pressure (EPWP) in the backfill. These results were compared to those of the quay wall without the CDM to elucidate the advantages of this method. In addition, the influence of some factors on the quay wall behavior, such as earthquake excitation characteristics, CDM area, and CDM strength, was also evaluated. The results demonstrated that the ground improvement using the CDM significantly decreased the bending moment and displacement of the sheet pile wall. The excitation characteristics did not affect the deformed shape of the sheet pile. With the constant CDM depth, the sheet pile displacement decreased with an increase in the improvement width until it reached a limitation. The increasing CDM strength also decreased the displacement of the wall until it raised a certain value. This demonstrated that this method was technically feasible, and it could be considered to study further by experiment before applying in practice.

Effectiveness of concrete rigid inclusions for coastal reclaimed liquefiable soils

Various ground improvement methods have been utilized to reduce the risk of liquefaction and associated soil deformations. Limited research has been reported in literature pertaining the effectiveness of concrete rigid inclusions in reducing the liquefaction-induced deformations. This paper displays the outcomes of a numerical study that investigates the effectiveness of concrete rigid inclusions in mitigating liquefaction-induced deformation of coastal reclaimed liquefiable soils. For this purpose, series of numerical analyses using 2D finite element software package GeoStudio 2012 were performed for different replacement area ratios and inclusion lengths in reclaimed deposits. The case history of caisson quay wall in Rokko Island from 1995 Kobe earthquake was used as a basis for the analysis and for model verification. The results showed that concrete rigid inclusions technique is efficient in reducing the permanent liquefaction-induced horizontal and vertical deformations of coastal reclaimed backfill and foundation deposits and provides better performance for subjected coastal structures.

Response of rigid drainage pile–superstructure–quay wall system under lateral spreading

Many examples of earthquake damage show that liquefied lateral spreading is the main cause of pile foundation failure. Rigid drainage piles (RDPs), with two drainage grooves and plastic drainage plates, are a new type of liquefaction-resistant pile that can take into account the bearing capacity and drainage function. A series of 1g shaking table tests was carried out to analyse the seismic response of an RDP–superstructure–quay wall system subjected to lateral spreading. Three levels of earthquake intensities – small (peak ground acceleration (PGA) of 0.05g), moderate (PGA = 0.1g) and large (PGA = 0.2g) – were investigated. The improvement in the anti-liquefaction performance using RDPs was analysed. The influences of far-field (FF) and near-field (NF) ground motions were also examined. The experimental results showed that RDPs can effectively reduce the liquefaction degree and the horizontal flow of the sand stratum. In addition, the internal force and displacement of the superstructure built on RDPs were small. The seismic response due to NF ground motion was found to be more significant than that of the FF ground motion, but the effects of FF ground motion cannot be disregarded. The results of the tests could provide useful information for the design of RDP groups in a typical pile–superstructure–quay wall system.

Numerical study on response characteristics of a caisson-type quay wall subjected to bidirectional ground shaking

The aim of this paper is to use numerical simulations to elucidate the effect of liquid–quay wall interaction on the seismic behavior of caisson-type quay wall subjected to real ground motions, assuming irrotational and inviscid flows. Three-dimensional, time-domain, dynamic analysis of a typical caisson-type quay wall is carried out using a coupled Lagrangian-Eulerian scheme, and six real excitation records are applied as ground vibration. The geometric complexity in the bounded caisson–seawater–backfill/foundation system is handled in the finite element method (FEM) using deformable 3D mesh where each structural medium can be discretized independently. The performance of the present coupled numerical analysis approach is validated against available numerical predictions, exhibiting good agreement with benchmark data. The response is appraised in terms of excess pore water pressure generated in the porous media, soil–sea–structure's residual displacements, and induced hydrodynamic pressures during the earthquake excitation. The numerical procedure demonstrates that excitation frequency spectrum in different intensity altitudes plays a crucial role in the behavior of quay walls and special attention must be given to gain a better understanding on the dynamic responses of such coupled systems.

Factors favouring vegetation in quay masonry walls: A pilot field study

Walls overgrown with plants can have a positive impact on urban comfort and contribute to biodiversity in the city. In particular, quay walls, thanks to their close contact with water, have the potential to be ecologically engineered to encourage the growth of herbaceous plants. Different factors can affect growth of vegetation on walls. This research aims at experimentally investigating the effect of several variables, including quay wall design, building materials and environmental conditions, on receptivity of brick masonry quay walls for herbaceous plants. To this scope, ten quay walls (size 2 m × 2 m x 0.43 m), have been built and placed in a canal in the city of Breda (the Netherlands). The survival and growth of vegetation and the moisture content in the wall were monitored during a period of about 2 years. The results show that the presence of a layer of soil substrate with high capillary suction, positioned in between the masonry cladding and the concrete structure of the wall, has the most relevant positive effect on vegetation growth on the masonry. Mortar composition and irregularities of the wall surface influence bio-receptivity too, but to a less extent; orientation had only a limited effect. Moreover, the strategy of using a mechanically strong bedding mortar in combination with a weaker but more bio-receptive pointing mortar has proven successful at favouring growth of herbaceous plants, while providing sufficient strength to the masonry.

A Simplified Deformation Estimation Method for Anchor Piles of Sheet Pile Quay Walls under Kinematic Forces during Earthquakes

In the seismic design of quay walls, it is necessary to evaluate the deformation of the walls during earthquakes as well as the safety of structural members. However, conventional seismic design methods for sheet pile quay walls cannot accurately determine the degree of deformation. One reason for this is that conventional methods do not consider kinematic forces acting on an anchor pile due to the deformation of the ground. This study proposes a simplified estimation method for anchor pile deformation under the influence of kinematic forces. The results of two-dimensional finite element analysis reveal that anchor pile deformation involves rotational and translational components caused by the kinematic forces, which the conventional methods do not consider. The deformation of the anchor pile caused by kinematic forces was 30%–40% of the total deformation at the pile head. It was clarified that unlike horizontally stratified ground, shear stress is generated in the ground before an earthquake resulting in the kinematic force acting on the anchor pile during the earthquake. Furthermore, a simplified method for estimating the deformation of the anchor pile under kinematic forces that uses one-dimensional seismic response analysis considering the predicted shear stress based on a theoretical equation is proposed. It was demonstrated that the proposed method accurately reproduces the anchor pile deformation.

Evaluating Finn-Byrne Model in Liquefaction Analysis of Quay Wall and Cantilevered Retaining Wall Models

Two centrifuge tests on a quay wall and a cantilevered retaining wall with saturated granular backfills were simulated using Finn-Byrne model. Capabilities of Finn-Byrne model in liquefaction analysis of the quay wall and the cantilevered retaining wall were evaluated. The quay wall model subjected to a horizontal acceleration time history and the cantilevered retaining wall model subjected to a horizontal and a vertical time history. The constitutive model is a linear elastic – perfectly plastic model. Hooke’s elasticity and Mohr-coulomb criterion for the yield surface were assumed for the backfill material behavior. The excess porewater pressure generation, acceleration, wall lateral displacement, lateral earth pressures, deformation pattern, and backfill settlements were monitored and compared with centrifuge tests’ results. The results showed that the adopted model is suitable for stability and displacement analyses of the quay walls and cantilevered retaining walls. However, a care should be taken when assessing the backfill settlements and dynamic earth pressure behind the wall stem. The rest of the results showed a good agreement with the centrifuge tests’ results.

Response of soil–pile–superstructure–quay wall system to lateral displacement under horizontal and vertical earthquake excitations

The excess pore water pressure generated under the combined vertical and horizontal earthquake excitations is generally greater than that under the unidirectional excitation, which may further affect the dynamic response of soil-pile-superstructure-quay wall (SPSQ) system. This study conducted a coupled effective-stress analysis for the response of SPSQ system to liquefaction-induced lateral displacement under horizontal and vertical earthquake excitations. To accurately describe the lateral displacement behind the quay wall, the liquefaction behavior of soils was described by a modified generalized plasticity model with parameters properly determined from laboratory tests. The numerical model of the SPSQ system was validated against the previously reported centrifuge model tests. The results show that the earthquake excitation with abundant low-frequency component causes greater residual lateral displacements of pile cap (ux,RC) and quay wall (ux,RQ) than that with abundant high-frequency component. The ux,RC and ux,RQ tend to increase as the peak vertical acceleration increases for both vertical and inclined piles. Increasing the fixity of the quay wall significantly reduces the influence of vertical ground motion on the ux,RC and ux,RQ. The polarity reversal of the vertical ground motion also has a significant effect on the ux,RC and ux,RQ and should be considered in the analyses. In addition, the lateral displacement of liquefied ground causes an amount of rotation of the cap of the inclined pile, probably leading to the potential shear failure at the head of piles. Special consideration should be given to the earthquake-induced shear force at deeper location because the shear force could be significantly greater than that at the head of both inclined and vertical piles in certain cases.

NUMERICAL ANALYSIS ON BEHAVIOR OF SHEET PILE QUAY WALL UNDER EARTHQUAKE LOADING USING TIME HISTORY METHOD

The sheet pile wall is used popular for coastal projects, and it is normally applied suitable for the ground had average or weak bearing capacity. Currently, when analysis and design this structure type under earthquake loading, almost documents and standards recomment to use response spectrum method, without much mention of the time-history method. This paper presented the method to evaluate the behavior of sheet pile quay wall using time-history method including liquefaction of soil by PLAXIS 2D program. The analysis was conducted based on the Vietnam standard and some foreign standards. The results focused on analysis and evaluate displacement and deformation of quay wall, the increase of excess pore pressure in the backfill with the time and liquefaction potention of the soil.

Ship Berthing and Unberthing Monitoring System in the Ferry Terminal

This paper presents a monitoring system designed to increase the safety of the quay structure in ferry terminals, in which, during berthing and unberthing maneuvers, propeller and thruster-generated jets may damage the seabed protection, threatening the stability of the berth structure. Direct measurement of flow velocity on the seabed is not possible due to the possibility of its damage, therefore dynamic pressure measurement of the quay wall was used within the system. The relationship between the pressure on the quay wall and flow velocity on the seabed was determined using real-scale CFD simulation of the flow field generated during berthing and unberthing maneuvers. The paper focuses on the computations of the pressure distribution generated by bow thrusters. These computations made it possible to determine the velocity field in the time domain. Their results, verified using real-scale measurements, are in line with generally accepted empirical methods.

Seismic performance and vulnerability of gravity quay wall in sites susceptible to liquefaction

Seismic performance and vulnerability of gravity quay wall in sites susceptible to liquefaction

Berth planning and real-time disruption recovery: a simulation study for a tidal port

With the increasing volume of container freight transport, future port planning is crucial. Simulation models provide a means to gain insight in the effects of terminal expansions. Detailed simulations incorporate berth allocation: assigning vessels a time and location at the quay wall, where the vessel is loaded and unloaded. This article develops decision models for both offline preliminary berth planning and for online recovery of this plan during simulation. First, we develop an optimisation-based approach that incorporates realistic aspects—cyclic vessel arrivals, tidal windows, and minimisation of vessel draught during low water periods—in order to develop a cyclic baseline berth allocation plan. The approach can proactively incorporate slack for increased robustness. Exploiting a constraint-based solver, we can obtain optimal or satisficing solutions for a year’s operation of a large port. The resulting preliminary berth plan is used as a basis for the arrival times. However, disruptions can occur, such as vessel arrival and loading times varying from the planned. Hence, second, we develop a real-time disruption management decision model. This multi-level heuristic approach reacts to disruptions while minimising perturbation of the original berth plan. Computational experiments with a high-resolution simulator show our recovery approach finds good solutions until a tipping point of disturbance. Results also show that when the expected occupation of a terminal is higher, strengthening robustness of the preliminary plan has increased importance. The approach described in the article is implemented for a major European inland tidal port, forming the basis of a simulation-based decision support tool for operational planning and exploring port expansion options.

Geotechnical reconnaissance findings of the October 30 2020, Mw7.0 Samos Island (Aegean Sea) earthquake

On October 30, 2020 14:51 (UTC), a moment magnitude (Mw) of 7.0 (USGS, EMSC) earthquake occurred in the Aegean Sea north of the island of Samos, Greece. Turkish and Hellenic geotechnical reconnaissance teams were deployed immediately after the event and their findings are documented herein. The predominantly observed failure mechanism was that of earthquake-induced liquefaction and its associated impacts. Such failures are presented and discussed together with a preliminary assessment of the performance of building foundations, slopes and deep excavations, retaining structures and quay walls. On the Anatolian side (Turkey), and with the exception of the Izmir-Bayrakli region where significant site effects were observed, no major geotechnical effects were observed in the form of foundation failures, surface manifestation of liquefaction and lateral soil spreading, rock falls/landslides, failures of deep excavations, retaining structures, quay walls, and subway tunnels. In Samos (Greece), evidence of liquefaction, lateral spreading and damage to quay walls in ports were observed on the northern side of the island. Despite the proximity to the fault (about 10 km), the amplitude and the duration of shaking, the associated liquefaction phenomena were not pervasive. It is further unclear whether the damage to quay walls was due to liquefaction of the underlying soil, or merely due to the inertia of those structures, in conjunction with the presence of soft (yet not necessarily liquefied) foundation soil. A number of rockfalls/landslides were observed but the relevant phenomena were not particularly severe. Similar to the Anatolian side, no failures of engineered retaining structures and major infrastructure such as dams, bridges, viaducts, tunnels were observed in the island of Samos which can be mostly attributed to the lack of such infrastructure.

Soil-pile-quay wall interaction in liquefaction-induced lateral spreading ground

Earthquake-induced soil liquefaction and lateral spreading often causes damage to pile foundations of quays and offshore structures. In this study, the soil-pile-quay wall interaction in liquefaction-induced lateral spreading ground was analyzed from three perspectives—experimental investigation, numerical simulation, and parametric analysis. A large-scale (1 g acceleration) shake-table test was conducted on a 2 × 2 pile group behind a quay wall, and described in terms of sensor arrangement, model configuration, and test results. The test resulted in phenomena such as the quay wall overturning to the water side, and ground settlement. A 2D (two-dimensional) nonlinear FE (finite element) model of a coupled dynamic soil-water system, which considered soil-pile-quay wall interactions, was validated using the experimental data. Based on the validated model, a parametric study was conducted to illuminate the effects of the pile head fixing conditions, pile stiffness, superstructure mass, permeability coefficient, and acceleration. The results indicated that these parameters had a significant influence on the soil-pile-quay wall interaction in the liquefaction-induced lateral spreading ground. Investigating the effects of each of the five parameters on the dynamic performance of pile foundations in this study has guiding implications for tests and numerical simulations.

Experimental and Numerical Investigations on the Moment Capacity and Stability of Z‐shaped Steel Piles

AbstractHarbour structures like quay walls or construction pit walls in civil engineering are often built up with steel sheet piles. Aside of U‐steel sheet piles also Z‐shaped piles with interlocks are widely used in such structures. The pressure on costs and efficiency and the competition in this field lead to the necessity of increased efficiency in design. To benefit from the potentials in the bending moment capacity of semi‐compact Z‐shaped steel sheet piles forming the infills of combined walls, four‐point‐bending tests were carried out by the Institute of Structural Design at the Materials Testing Institute in Stuttgart in 2019. A FE‐model was validated by back‐calculating the tests, followed by an extensive parametric study (GMNIA) with different Z‐piles. Among others the different geometries, which lead to different b/t‐ratios and the steel grade were varied leading to a different compression flange slenderness. In addition, the lock state was varied to investigate the impact on the bending moment capacity as: Free lock rotation, crimped interlocks with different crimping densities and fully welded over the entire length. Three resistance models were investigated and evaluated for further development of Eurocode 3 Part 5. The FE model was simplified and further developed for stability analyses. This was followed by a parametric study aimed to investigate the stability of Z‐shaped steel sheet piles under axial loads.

Investigating the effect of terminals’ service attributes on attracting shipping lines: a stated choice approach

Container terminals in the Mediterranean region have a high competition level between them to achieve a greater share of the regional seaborne trade volume. The national container companies in Egypt face low performance and productivity issues because liners prefer other ports/terminals in the East Mediterranean. One reason for this problem is due to policy makers’ belief that spending much money on terminal infra- and super-structure is the best practice for attracting more shippers. However, terminal capital investments and yearly maintenance costs are substantial and may not be useful if other factors control port/terminal choice from a shipping company’s point of view. Recently, the Egyptian Maritime Transport Sector went through a number of new projects through the construction of quay walls, yards, and terminals in various Egyptian ports such as Alexandria, Abu Kir, and El-Sokhna in attempt to improve the available freight capacity (i.e. supply)Nevertheless, and as long as shippers insist on choosing a specific port/terminal, such new improvements may not reap their intended benefits. This research investigates the important factors that control shipping liners decisions when selecting a container terminal by using a custom-made instrument design. Two data collection methods are used; namely, Revealed Preference (RP) and Stated Preference (SP) or Stated Choice (SC). Then, discrete choice models of terminal switching behavior will be used to help policy makers prescribe efficient strategies to alter shipping lines decisions and ensure that each port/container terminal has a fair market share. However, this paper reports only on the first part, while the latter is still work in progress. The preliminary data analysis showed that port charges and port infrastructure are the most critical factors shipping lines look for when choosing a container terminal. As such, policy makers need to focus on these factors in attempt to promote their terminals and make them more attractive to shipping lines.

Numerical Back-analysis of Caisson Quay Walls in the Yeong-il Bay Port during the 2017 Pohang Earthquake

The performance of nonlinear response history analysis was analyzed based on the historic case of the 2017 Pohang earthquake in Korea. The Yeong-il bay container terminal stopped operations for a period after the Pohang earthquake and intensive site and hazard investigations were conducted. Nonlinear response history analyses using various soil constitutive models, including sophisticated liquefaction models, were performed on the caisson quay wall under two-dimensional plane strain condition. The results of analysis were compared to the hazard investigation results. The analysis results exhibit reasonable agreement with the field measurement data for the earthquake-induced permanent displacement of the quay wall and quay crane rails.

Hydrodynamic analysis of resonant waves within the gap between a vessel and a vertical quay wall

Concerning the side-by-side offloading operations at gravity-based terminals, the wave interaction with a vessel alongside a long vertical wall in both normal and oblique seas was investigated. The imaging principle was applied to convert the original to an equivalent wave-diffraction problem by two symmetrical vessels in open seas exposed to bi-directional incident waves. The boundary integral equation method, in conjunction with a higher-order boundary element method (HOBEM), was used to solve the equivalent problem. Besides the linear free-surface elevation and wave loads, the second-order mean wave drift loads on the vessel was calculated based on either the direct pressure integration or using a semi-cylindrical control surface. Moreover, the solution was also developed for the oblique wave interaction with a two-dimensional barge-wall system using the eigenfunction expansion matching method. Systemic numerical studies were then conducted for the cases of a rectangular barge and a Wigley hull in close proximity to a long wall, respectively. Under oblique incidence, both the odd and even modes of fluid motion within the gap can be induced. In the case of a rectangular barge, the linear wave force can be obviously amplified at the location of the (1, 0) resonant mode, while the linear wave moment at the (2, 0) mode. In addition, the negative mean force along the transverse direction, which tends to push the barge away from the wall, can be apparently enhanced at both the odd and even resonant modes. Besides, in oblique seas, the (1, 0) resonant mode can give rise to the significant amplification of the positive mean yaw moment around the centre of the cross-sectional area of the barge, which tends to pull the stern of the barge (that faces incident waves) closer to the wall, while pushing the bow away from the wall. Such amplification gets less noticeable for higher modes. Numerical results also indicate that the hull geometry imposes a significant impact on the resonant waves in the gap. In the case of a Wigley hull, the amplification of the free-surface response is much less apparent when compared with a rectangular barge.

Relationship between eroded volume and main scour hole dimensions near quay walls caused by internal counter-rotating twin-propellers

The present study aims at computing and analysing the eroded sediment volumes induced by twin-propeller jets near a vertical quay wall from the main geometric characteristics of the scour hole. Two different scouring mechanisms govern the scouring process: i) the down-flow due to the interaction between the propellers jet and the wall, and ii) the direct impact of the propellers jet flow on the seabed. For this reason, the whole study area is divided into two subzones: 1) 'near the wall' field; 2) 'far from the wall' field. Both forward and backward rotation of the propellers during manoeuvring are analysed. The results show that, for the two manoeuvring states, the relationship between the eroded volume and the geometric characteristics of the scour hole in the near-wall subzone does not change, meaning that the backward rotation does not affect the morphology of the scour hole near the wall. Moreover, the eroded volume can be determined as a function of the maximum depth near the wall and, with higher accuracy, as a product of the three main geometric characteristics of the scour hole at any time-stage during the scour hole development.