An Approach to Stability Analysis of Embedded Large-Diameter Cylinder Quay

The large-diameter cylinder structure, which is made of large successive bottomless cylinders placed on foundation bed or partly driven into soil, is a recently developed retaining structure in China. It can be used in port, coastal and offshore works. The method for stability analysis of the large-diameter cylinder structure, especially for stability analysis of the embedded large-diameter cylinder structure, is an important issue. In this paper, an idea is presented that is, embedded large-diameter cylinder quays can be divided into two types, i.e. the gravity wall type and the cylinder pile wall type. A method for stability analysis of the large-diameter cylinder quay of the cylinder pile wall type is developed and a method for stability analysis of the large-diameter cylinder quay of the gravity wall type is also proposed. The effect of significant parameters on the stability of the large-diameter cylinder quay of the cylinder pile wall type is investigated through numerical calculation.

Hydrodynamic Coefficients and Wave Excitation Forces for A Ship near A Quay

In this paper, the effects of a quay or a solid jetty on hydrodynamic coefficients and vertical wave excitation forces on a ship with or without forward speed are discussed. A modified simple Green function technique is used to calculate the 2D coefficients while the strip theory is used to calculate the 3D coefficients. Wave excitation forces are also calculated with the strip theory. Numerical results are provided for hydrodynamic coefficients and vertical wave excitation forces on a 200 000 DWT tanker ship. It is found that the quay has a considerable effect on the hydrodynamic coefficients and wave excitation forces for a ship.

Integration of Berth Allocation and Quay Crane Assignment in Tidal Container Ports

Tide is a significant factor which interferes with the berthing and departing operations of vessels in tidal ports. It is a preferable way to incorporate this factor into the simultaneous berth allocation and quay crane( QC) assignment problem( BACAP) in order to facilitate the realistic decision-making process at container terminal. For this purpose,an integrated optimization model is built with tidal time windows as forbidden intervals for berthing or departing. A hind-and-fore adjustment heuristic is proposed and applied under an iterative optimization framework. Numerical experiment shows the satisfying performance of the proposed algorithm.

Prediction Method of Seismic Residual Deformation of Caisson Quay Wall in Liquefied Foundation

The multi-spring shear mechanism plastic model in this paper is defined in strain space to simulate pore pressure generation and development in sands under cyclic loading and undrained conditions, and the rotation of principal stresses can also be simulated by the model with cyclic behavior of anisotropic consolidated sands. Seismic residual deformations of typical caisson quay walls under different engineering situations are analyzed in detail by the plastic model, and then an index of liquefaction extent is applied to describe the regularity of seismic residual deformation of caisson quay wall top under different engineering situations. Some correlated prediction formulas are derived from the results of regression analysis between seismic residual deformation of quay wall top and extent of liquefaction in the relative safety backfill sand site. Finally, the rationality and the reliability of the prediction methods are validated by test results of a 120 g-centrifuge shaking table, and the comparisons show that some reliable seismic residual deformation of caisson quay can be predicted by appropriate prediction formulas and appropriate index of liquefaction extent.

Dynamic Responses of Block Type Quay Walls Under Cyclic Loading

The purpose of this research is to study the dynamic responses of gravity quay walls with block type consisting of“three blocks”experimentally.For this purpose,1g shaking table tests were conducted under different cyclic loadings for two different saturated granular backfill materials(Soil 1 and Soil 2).In this study,D_(n50) of Soil 1 and Soil 2 are selected as 2.2 cm and 1.0 cm,respectively.During the experiments,accelerations,soil pressures and displacements were measured for each block.Test results pointed out that Soil 2 caused more damage on structures.The measurements for displacement and tilting of each block were discussed in view of“acceptable level of damage in performance-based design”given in PIANC(2001).The result of the study showed that the definitions of damaged levels given in PIANC(2001)were reliable for using in performance-based methods for seismic design of block type quay walls.

Research on the Prediction of Quay Crane Resource Hour based on Ensemble Learning

In Container terminals,a quay crane’s resource hour is affected by various complex nonlinear factors,and it is not easy to make a forecast quickly and accurately.Most ports adopt the empirical estimation method at present,and most of the studies assumed that accurate quay crane’s resource hour could be obtained in advance.Through the ensemble learning(EL)method,the influence factors and correlation of quay crane’s resources hour were analyzed based on a large amount of historical data.A multi-factor ensemble learning estimation model based quay crane’s resource hour was established.Through a numerical example,it is finally found that Adaboost algorithm has the best effect of prediction,with an error of 1.5%.Through the example analysis,it comes to a conclusion:the error is 131.86%estimated by the experience method.It will lead that subsequent shipping cannot be serviced as scheduled,increasing the equipment wait time and preparation time,and generating additional cost and energy consumption.In contrast,the error based Adaboost learning estimation method is 12.72%.So Adaboost has better performance.

Development of Maritime Mix-Type Structures

Mixed-type structures combining the advantages of pile constructions(low material consumption and possibility to erect on weak soils)and gravity walls(high bearing capacity and stability,good reliability and durability)are considered and improved.The sphere of application,main peculiarities,and practical technological aspects of these structures’implementation are analyzed.

Experimental Study of Perforated Caisson Breakwater

This paper describes the design of a perforated caisson breakwater and presents the results of model test. Tests with regular and irregular waves have demonstrated that the perforated caisson breakwater has the advantages of low reflection coefficient, good wave-absorbing performance, relatively small wave height in front of the breakwater, and small amount of overtopping. Analyses have been made of the coefficient of reflection, wave height in front of the breakwater, and wave overtopping. Relevant figures and tables are presented for reference.

基于模拟减少集装箱船待港时间的实用方法(英文)

The main challenge for container ports is the planning required for berthing container ships while docked in port.Growth of containerization is creating problems for ports and container terminals as they reach their capacity limits of various resources which increasingly leads to traffic and port congestion.Good planning and management of container terminal operations reduces waiting time for liner ships.Reducing the waiting time improves the terminal’s productivity and decreases the port difficulties.Two important keys to reducing waiting time with berth allocation are determining suitable access channel depths and increasing the number of berths which in this paper are studied and analyzed as practical solutions.Simulation based analysis is the only way to understand how various resources interact with each other and how they are affected in the berthing time of ships.We used the Enterprise Dynamics software to produce simulation models due to the complexity and nature of the problems.We further present case study for berth allocation simulation of the biggest container terminal in Iran and the optimum access channel depth and the number of berths are obtained from simulation results.The results show a significant reduction in the waiting time for container ships and can be useful for major functions in operations and development of container ship terminals.

AN ANT COLONY ALGORITHM FOR YARD TRUCK SCHEDULING AND YARD LOCATION ASSIGNMENT PROBLEMS WITH PRECEDENCE CONSTRAINTS

This paper examines the yard truck scheduling,the yard location assignment for discharging containers,and the quay crane scheduling in container terminals.Taking into account the practical situation,we paid special attention to the loading and discharging precedence relationships between containers in the quay crane operations.A Mixed Integer Program（MIP） model is constructed,and a two-stage heuristic algorithm is proposed.In the first stage an Ant Colony Optimization（ACO） algorithm is employed to generate the yard location assignment for discharging containers.In the second stage,the integration of the yard truck scheduling and the quay crane scheduling is a flexible job shop problem,and an efficient greedy algorithm and a local search algorithm are proposed. Extensive numerical experiments are conducted to test the performance of the proposed algorithms.