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Under excessive yard heaped loads, slopes are deformed, and piles are inclined, which may lead to the catastrophic failure of a pile-supported wharf. In this paper, centrifugal model tests were conducted to examine the effect of a newly proposed “m” shaped soil cement mixing (SCM) wall in the reinforcement of a pile-supported wharf. The “m” wall was constructed in the connecting section between the bent and loading yard. The performances of the bent with and without the “m” wall under yard heaped loads, i.e., the bent displacements, bending moments of the piles and earth pressures ahead of the piles, were compared to illustrate the reinforcement effects. The mechanism of the “m” wall in reinforcing the pile-supported wharf was also discussed. Test results indicate that the bent displacements were lessened and the ultimate bearing yard heaped loads increased with the “m” wall. The “m” wall reduced the bending moments of the piles, particularly in the middle and rear sections of the bent. The earth pressures ahead of piles were generally lower with than without the “m” wall. The “m” wall limited the integral translation of the slope induced by the yard heaped loads; thus, the compression of the surrounding soil to the piles was relieved, effectively protecting the bent from destruction.

Model tests aimed at investigating the wave-induced dynamic response and instability of silty clay seabeds around a semi-circular breakwater were conducted in a large wave flume. The pattern of wave forces was measured and analysed. The seabed responses were presented in terms of pore pressure and vertical stress, which were further characterized in terms of their oscillatory and residual values. The wave-induced settlement and instability of the semi-circular breakwater were studied. Test results reveal that the total horizontal wave force was generally greater than the vertical wave force, and a phase difference existed in the total horizontal and vertical wave force patterns. The trends in the oscillatory pore pressure and vertical stress were very similar: they generally developed rapidly in the seabed on the wave side, tended to be larger in the upper silty clay and smaller in the bottom area and increased with increasing wave height. Furthermore, the oscillatory responses mostly reached stable states but were observed to vibrate with cyclic time in the destroyed silty clay. The residual pore pressure and vertical stress mainly developed in the seabed around the breakwater and could be quite different depending on the location. With the exception of the decrease-increase tendency in some seabed areas, the residual pore pressure generally increased with cyclic time beneath the breakwater. The residual vertical stress generally increased with cyclic time beneath the breakwater, except in some regions beneath the toes of the internal rubble bed. The semi-circular breakwater settled substantially into the silty clay seabed, and the settlement was greater on the wave side. This seabed shear failure is attributed to the strength degradation of the silty clay induced by the development of excess pore pressure and the destruction of the soil fabric.

Floating oil booms are commonly-adopted facility to collect spilled oil on sea surface, or to protect specific areas against oil slick spreading. In this study, 931 runs of laboratory test were carried out under wave-current coupling conditions to investigate hydrodynamic performances of the flexible floating oil boom. The tests first conducted a comparison on motion responses between the flexible floating boom and the rigid one to indicate the necessity of taking the flexibility of boom into consideration. Then a comprehensive analysis was carried out to investigate the effects of the ambient currents, waves and the boom characteristics of material stiffness, diameter of floater, length of skirt, and B/W (Buoyancy/Weight) ratio on the motion responses of the flexible floating booms. Finally, by taking the water blockage effect in front of the boom into consideration in the definition of boom effectiveness, the effective draft and freeboard were compared between the flexible boom and rigid one under fixed current and wave conditions. The effects of currents, waves, skirt lengths and B/W ratios on the effective draft and effective freeboard are assessed.

Containment booms are commonly used in collecting and containing spilled oil on the sea surface and in protecting specific sea areas against oil slick spreading. In the present study, a numerical model is proposed based on the N-S equations in a mesh frame. The proposed model tracks the outline of the floating boom in motion by using the fractional area/volume obstacle representation technique. The boom motion is then simulated by the technique of general moving object. The simulated results of the rigid oil boom motions are validated against the experimental results. Then, the failure mechanism of the boom is investigated through numerical experiments. Based on the numerical results, the effects of boom parameters and dynamic factors on the oil containment performance are also assessed.

As a new breakwater foundation form, a bucket foundation with two skirted side semicircles and a skirted middle rectangle was applied to the breakwater project at Xuyu Port, China. A series of laboratory tests were performed on the bucket foundation to investigate the vertical bearing capacity and the bucket-sand interaction mechanisms during the load bearing process. The main failure mode of the bucket foundation under vertical loading was general shear failure. The vertical loads increased with penetration displacement, ultimately reaching 330~404 kN with a displacement criterion of 0.06De (equivalent diameter of the foundation) at different incremental load steps. The inner soil pressures were clearly greater than the outer soil pressures induced by the skirt constraint effect. Regarding the bearing capacity, the outer skirt friction decreasing from approximately 0.05 to 0 with increasing penetration displacement, contributed only slightly, while the foundation base provided the majority. The cover plate resistance increased rapidly after the penetration displacement exceeded 25 mm, and its sharing ratio ultimately reached approximately 0.82. The tip resistance was estimated via the assistance of the cone resistance, and its sharing ratio decreased with penetration displacement. The inner friction and corresponding friction coefficient first increased and then decreased with penetration displacement, reaching a final sharing ratio of approximately 0.14.

A new kind of hydrophobic and oil sorbent based on jute fiber was successfully prepared by the integration of silica onto a fiber surface via the sol-gel method and subsequent hydrophobic modification with octadecyltrichlorosilane (OTS). Compared with the hydrophilic raw fiber, the modified fiber had a water contact angle (CA) of 136.2°, suggesting that the material has good hydrophobicity. Furthermore, the ability of oil in the oil/water system (taking diesel for example) to absorb was revealed by the kinetics, the isotherm equation, and the thermodynamic parameters. Adsorption behavior was kinetically investigated using pseudo first-order and pseudo second-order models. The data mostly correlated with the pseudo first-order model. The equilibrium adsorption at 298 K was assessed by using the Langmuir and Freundlich isotherm models. The Freundlich model had greater consistency with the experimental data. The obtained thermodynamic parameters demonstrate that the adsorption of diesel is spontaneous, favorable, and exothermic.