Construction Of Artificial Islands Research Articles

Review of artificial island construction technology and innovative approaches to synchronous construction

Review of artificial island construction technology and innovative approaches to synchronous construction

A Robust Multi-Objective Evolutionary Framework for Artificial Island Construction Scheduling Under Dynamic Constraints

Artificial island construction is a multifaceted engineering endeavor that demands precise scheduling to optimize resource allocation, control costs, ensure safety, and minimize environmental impact within dynamic marine environments. This study introduces a comprehensive multi-objective optimization model that integrates critical factors such as resource limitations, task dependencies, environmental variability, safety risks, and regulatory compliance. To effectively address the complexities of this model, we develop and employ the Multi-Objective Adaptive Cooperative Evolutionary Marine Genetic Algorithm (MACEMGA). MACEMGA combines cooperative coevolution, adaptive dynamic weighting, dynamic penalty functions, and advanced genetic operators to navigate the solution space efficiently and identify Pareto optimal schedules. Through extensive computational experiments using data from the Dalian Bay Cross-Sea Traffic Engineering project, MACEMGA is benchmarked against algorithms such as NSGA-II, SPEA2, and MOEA/D. The results demonstrate that MACEMGA achieves a reduction in construction time from 32.8 to 23.5 months and cost savings from CNY 4105.3 million to CNY 3650.0 million while maintaining high-quality outcomes and compliance with environmental standards. Additionally, MACEMGA shows improvements in hypervolume by up to 15% over existing methods and a Convergence Rate that is 8% faster than MOEA/D.

Numerical simulation on the influence of artificial island on reef hydrodynamics

The construction of artificial island can greatly change the reef hydrodynamics, leading to increased water level and wave height as well as changes in flow field distribution. These alterations can affect sediment transport on the reef, and increase the risk of overtopping and structure instability. A numerical model based on the Reynolds Averaged Navier-Stokes (RANS) equations and k-ε turbulence closure model was developed to investigate the influence of artificial island on reef hydrodynamics. The numerical model was validated against the experimental results of wave height, mean water level, and wave breaking morphology. Detailed flow field, wave height, and wave set-up in front of artificial island were further analyzed based on the validated model. After building the reef-top structure, the wave breaking and offshore currents at reef edge were amplified. The flow stratification and increase of the wave set-up were also found on the reef flat. Furthermore, we found the relationship between maximum flow velocities on the reef flat and incoming wave conditions could be characterized by two non-dimensional parameters: |u¯|max/g(η¯+hr), (η¯+hr)/Hi.

Bearing capacity of large-diameter pile foundation under combined VHM loadings in soft clay

ABSTRACT The large-diameter pile foundation is with an intermediate depth, widely used in engineering fields such as ports, breakwaters and rapid construction of artificial islands as a supporting structure to resist lateral loads. However, there is limited research on the bearing performance of such large-diameter, intermediate-depth pile foundations. In this paper, the finite element method is used to investigate the bearing capacity of the large-diameter pile foundation with different embedment ratios in homogeneous soil and normally consolidated soil and the prediction formulas for uniaxial and combined bearing capacity are developed. This study also sets up three different skirt wall–soil interface properties to discuss their influence on the bearing performance of the large-diameter pile foundation. The research is systematic, and relevant analysis can provide practical suggestions for engineering design.

Mechanical behavior of EICP-treated calcareous sands under high confining pressures

Calcareous sands are widely distributed on the coral reefs, continental shelf, and seashores between 30° north and south latitude and are commonly utilized as filling materials for the construction of artificial islands and infrastructure foundations. In this study, calcareous sands were cemented by enzymatically induced carbonate precipitations (EICP) technique. Drained triaxial tests were conducted on the EICP-treated calcareous sands. Results showed that the specimens with different cementation levels exhibited different responses in mechanical behavior. The differences in the sand fabric after consolidation under a relatively high confining pressure resulted in the untreated specimen exhibiting a higher peak strength compared to the lightly cemented specimen. High confining pressures exhibited a strongly inhibiting effect on dilatancy, which could be counteracted by increasing the cementation level. The EICP-treated specimen could have one or two yield points (smaller-strain and larger-strain yields). For lightly cemented specimens, the smaller-strain yield stress decreased under high confining pressures due to the partial carbonate bonding degradation during consolidation. The stress line of untreated particle breakage (UPB) was a critical boundary to distinguish failure mode in the p’ -q space. For the EICP-treated specimens, the yield stress located above or below the UPB stress line indicates the simultaneous or sequential breakage of the carbonate bonding and sand particles, respectively. Accordingly, the EICP-treated specimen exhibited brittle or ductile properties. Failure mode transformation could be triggered by increasing cementation level or confining pressure.

Geomorphological processes following the construction of an offshore artificial island in the radial sand ridges of the South Yellow Sea

Offshore artificial islands represent a novel way to develop and utilize marine space resources. Previous research has focused on predicting erosion and deposition distributions following the islands construction, utilizing laboratory experiments and numerical simulations. However, the absence of long-term continuous monitoring has hindered systematic studies on the geomorphological processes of these islands. A 20-years of underwater terrain monitoring scheme was conducted before and after construction of the Rudong Artificial Island in Jiangsu Province, China. The results were combined with on-site observations of tidal currents, suspended sediment concentrations, and surficial sediment to investigate the evolution of the water channel–sand ridge system and the development process of local scour around the artificial island. The results indicated that after the construction of the artificial island, its surrounding water channels showed an overall evolution trend of the north channel shifting towards the north, the middle channel widening and moving south, and the south channel extending westward and southward. Scour has been observed at the four corners of the artificial island, with the peak depths of 7.3 m, 5.6 m, 13.7 m, and 12.2 m at the southwest, northwest, northeast, and southeast corners respectively. The scour in the southwest and northwest corners reached an equilibrium within five years. However, in the southeast corner, continuous erosion of the shoal on the southeast side of the artificial island enhanced the local hydrodynamic force, leading to further scour development. The large-scale scour in the northeast corner was mainly caused by changes in the local flow field following the construction of water intake pipelines and their protection projects. These geomorphological changes are the joint results of the natural evolution of the radial sand ridges and local erosion and deposition from engineering construction. Currently, the sandbanks surrounding the island are still undergoing dynamic evolution following engineering construction, and local scour around the island has not yet reached equilibrium.

Artificial islands in modern development: Construction, applications, and environmental challenges

Artificial islands are extensively utilized in urban development, ports, and tourism projects worldwide, but they also present numerous ecological and environmental challenges. This study provides a comprehensive review of the principal applications of modern artificial islands as well as their development trends. All artificial islands dating back to the eighteenth century have been compiled, encompassing their locations, construction, and purposes. The main content of this review is in three different directions: (1) artificial islands are categorized into six groups: application-based groups and arranged chronologically, providing insights into the growth patterns of each category; (2) three common island-building types: cofferdam island, reef island and floating island, and the related techniques are summarized and (3) the challenges faced by the construction of artificial islands are presented along with the suggestions and expectations. This review is intended to provide some inspiration for future research on artificial islands.

The Legal Framework for Artificial Energy Islands in the Northern Seas

Abstract Belgium, Denmark and the Netherlands have announced their interest in constructing artificial ‘energy islands’ to enable the integration of large-scale offshore wind energy into the energy system. This raises several legal questions, such as how do these developments fit in the balance of interests required by the United Nations Convention on the Law of the Sea, what European Union law is applicable to artificial islands and how Belgium, Denmark and the Netherlands approach the construction of artificial islands. This article provides a comprehensive overview of the applicable legal framework and shows the variety of approaches and strategic choices States may have when developing energy islands.

The artificial islands of Vietnam in the South China Sea

The militarisation of the South China Sea has specific implications for the regional security situation. The construction of artificial islands and platforms by the states of the region leads, on the one hand, to the assertion of their possessions and the enhancement of their security and, on the other hand, contributes to rising tensions in the region. The construction of such facilities by Vietnam goes unchallenged, there is no criticism and even some support – not so with China. Most countries see Vietnam as the country most able to stand up to its large neighbour. Vietnam otherwise operates more slowly and on a smaller scale, so it is commonly seen as defensive as it builds on islands that have belonged to Hanoi for decades and are close to the mainland coast.

Fantastical infrastructure imagining: The Meg and The Wandering Earth as global science fiction cinema in the age of China’s rise

ABSTRACT This study is prompted by two of the most famous Hollywood blockbusters set above and below the ocean—The Abyss (1989) and Waterworld (1995). These films tell us something about catastrophic environmental degradation as much as they point us to the cultural power that is embedded in deep-sea structures and vehicles: the underwater drilling platform, built-up steampunk atolls and submersibles. The continuation of this fantastical infrastructure imagining occurs out at sea in The Meg (2018) and underground in The Wandering Earth (2019). As new Chinese science fiction films, each provide representations of other high-tech complexes—from an underwater research facility to massive Earth engines—each vying to show the struggles over technological ingenuity being usurped for military purposes. Thus, premonitions of China’s rise out at sea and off-world are argued to relate to its recent construction of artificial islands in the South China Sea. This is formulated by me to be a part of a “baseworld phenomenon.” An additional two tropes coalescence with The Meg and The Wandering Earth: mainly, that these films are part of an ever-expanding corpus of global SF cinema. Throughout the essay, the concept of “cultural pillarization”, where worlds created for Chinese audiences are partitioned and multiculturalism is compromised, is also analyzed.

Impacts of sea-access roads on wetland landscape dynamics in the Yellow River Delta front

The coevolution between oilfield development and deltaic wetlands is critical for ensuring environmental sustainability in mega-deltas. In the Yellow River Delta (YRD), the construction of offshore artificial islands and their sea-access roads (SARs) in delta fronts, providing accommodation for oilfields development of oilfields influences the evolution of adjacent wetland landscapes. This study utilized the threshold segmentation method based on MNDWI and the object-oriented random forest algorithm to extract the shoreline and classify typical wetland vegetation in the study area. It also analysed the impact of SAR on the landscape dynamics of coastal wetlands from 2004 to 2020. The results show that the SAR significantly affected the local sediment transport and erosion and accretion patterns in its adjacent coast, which has gone through accretion-domination, erosion, and continuous accretion stages, with significant accretion and erosion on the north and south sides of the SAR, respectively. From 2004 to 2020, 13.74 km2 of new-born wetland was formed, and the vegetation dynamics in the study area transformed from primary succession to human-disturbed succession. Spartina alterniflora (S. alterniflora) grew rapidly from 4.15 km2 to 18.04 km2 during 2010–2016, showed an imbalanced distribution on both sides of the SAR. This research can provide references for the sustainable coevolution of offshore oilfields and coastal environments.

Main trends and results of 300-years anthropogenic impact on the geological environment and ecosystem of the Eastern Gulf of Finland

The seafloor of the eastern Gulf of Finland (the Baltic Sea), especially its easternmost part – Neva Bay – has experienced anthropogenic impacts since the beginning of the XVIII century. The aim of this paper is: i) to analyze results of different stages of anthropogenic impact on the geological environment and ecosystem, ii) to assess the influence of dredging, dumping, and aggregates (sand, gravel) and ferromanganese concretions extraction on bottom relief and sedimentation processes, and iii) to establish the major spatial and temporal trends of heavy metal accumulation in the soft bottom sediments. Since the establishment of St. Petersburg, and into the 1960s, there was a physical impact on the seabed through the construction of artificial islands, dredging, and dumping. From 1960s to the 1990s, these types of activity became even more intense, as nearshore submarine terraces were used for sand and gravel extraction, and sediment pollution (e.g., heavy metals) has become one of the main environmental problems of the region. Based on extensive geochemical data collected for the first time in the study area, we examined a vertical distribution of heavy metals in cores obtained from different sedimentary basins. Results demonstrate a trend of increasing concentration values from the 1940s to the 1990s. Background concentrations of heavy metals are based on the geochemistry of catchment areas, decreasing in concentrations from the northwest to the southeast, while the maximum concentrations of hazardous substances deposited from the 1970s to the 1990s were observed in the easternmost part of the gulf. Since the 1990s the heavy metal input to the Gulf of Finland has significantly decreased, so the concentration of these hazardous substances in the surface sediments dropped as well, demonstrating a spatial distribution corresponding more to background (natural, pre-industrial) values. On the other hand, big hydrotechnical projects, realized during the last 20 years – artificial territories and new harbors construction, accompanying with dredging and dumping, ferromanganese concretion extraction, etc. – led to resuspension and secondary pollution of water. The other problem is the expansion of anoxic areas, caused both by climate change and human-stimulated eutrophication. Near-bottom anoxic conditions stimulate heavy metal migration from bottom sediments into the water column. All these processes impacted benthic communities as our review of previously published studies reveals. Geological and geophysical research revealed that within some areas anthropogenic impact caused a complete change of the sedimentation processes such as direction and rates of transport, which led to the total transformation of bottom relief, surface sediment distribution, and the benthic communities.

Long-term environmental impact of an artificial island of solidified dredged marine silt

Marine dredging silt that has been solidified is commonly used as a filler material for inland reclamation and artificial island construction. However, determining the long-term environmental safety of artificial islands made of solidified silt is a challenge. A bridge–tunnel conversion artificial island made of solidified silt was the research location of this study. Laboratory tests were conducted to study the effect of cement content on the pollutant pore-water concentration and hydraulic conductivity of solidified silt. The results showed that after solidification treatment, the heavy-metal concentration in the pore water of dredged silt reduced by 60–85%, whereas the concentration of hydroxide (OH−) ions increased 106–1070 times, and the hydraulic conductivity decreased by approximately three orders of magnitude. On the basis of the test results, the finite-element method was used for simulating the long-term transport of heavy metal nickel (II) (Ni2+) and hydroxide in artificial islands. When the cement content increased from 60 to 100 kg/m3, the nickel (II) concentration in the dam around the solidified silt decreased by approximately 68%, whereas the hydroxide concentration increased approximately tenfold. However, none of them exceeded the seawater water quality standard. This indicates that the long-term environmental safety of the artificial island could be ensured.

Recurrence of the green tide in the Bohai Sea, China: A green tide caused by coastal reclamation projects

Since 2015, a novel green tide began to bloom along the Qinhuangdao coastal area in the Bohai Sea, China. A year-round field survey was conducted in 2016 to reveal the development process of the green tides. The hydrodynamic comparison between 2004 and 2016 was carried out through model simulation. The results of field investigations indicated that the green tides lasted about five months from the early April to late September. The macroalgae in the green tides were mainly suspended to shallow waters, and the biomass peaked in July and August, after which they declined rapidly in September. The species composition of the macroalgae changed obviously during the blooming period. The model analysis showed that the construction of artificial islands affected the hydrodynamic force and weakened the water velocity. Therefore, based on the development process of the tides, we speculated that (1) the coastal eutrophication might be the major cause of the Qinhuangdao green tides, and (2) Slow flow was conducive to the growth of macroalgae, promote the formation of the green tide. (3) Seawater temperature might be one of the main factors controlling the succession of green tide species in Qinhuangdao.

Bearing capacity and deformation behavior of rigid strip footings on coral sand slopes

Porous coral sands formed by the remains of marine organisms are important foundation-filling materials for artificial island construction and other marine geotechnical projects. A typical situation is that the significantly reduced bearing capacity of a rigid footing adjacent to coral sand slopes threatens the safety and stability of the upper structures. In this study, a series of model-scale tests were conducted to investigate the bearing capacity and deformation behavior of a rigid strip footing resting on the top of coral sand slopes with consideration of the effects of edge distance, slope height, slope angle, number of geogrid layers, burial depth and spacing of the geogrid layer. The measured deformation field based on particle image velocimetry (PIV) technology indicates that the unreinforced coral sand slope is dominated by unilateral sliding patterns, and its bearing area is significantly smaller than that of the geogrid reinforced coral sand slope (GRCSS). The bearing capacity in unreinforced coral sand slopes increases with the increasing edge distance, and the decreasing slope height and angle. Although the geogrid reinforcement significantly improves the bearing capacity, it is also affected by the number of layers, burial depth and spacing between reinforcement layers. Besides, the reduction coefficient of bearing capacity (RCBC), the bearing capacity factor (Nγq) and the normalized bearing capacity (Nγq/NγqR) were further calculated and discussed based on the test results and classical bearing capacity theory.

Experimental Study on the Permeability of Microbial-Solidified Calcareous Sand Based on MICP

In the construction of artificial islands in distant seas, calcareous sand has been widely used as a foundation filler due to its excellent mechanical properties and extensive availability in the marine environment. How to store more fresh water on the artificial islands by reducing its permeability is currently a great challenge. Microbial-induced carbonate precipitation (MICP) has always been considered as a great potential method to improve the cemented properties of calcareous sand, but the effect of grain gradation on the permeability of MICP-improved calcareous sand remains unclear. In this research, a self-made device was developed to conduct MICP grouting and permeability tests, where the permeability coefficient (k) under different grain gradations (curvature coefficient (Cc) and uniformity coefficient (Cu)) was measured. A CT scan was conducted to investigate the variation in the porosity (n) of sand samples before and after MICP treatment. The weighting method was adopted to measure the content of induced calcium carbonate (M). A scanning electron microscopy (SEM) technique was used to further study the micromechanism of the MICP treatment. Finally, the correlations between the k of MICP-treated sand and Cu, as well as Cc, were semiquantitively analyzed. The results show that the magnitude of M, k and n changes are closely related to Cc and Cu. The reduction amount of k and n increased with the rise in Cc and Cu, and the increased amount of M increased with the rise in Cc and Cu. The SEM results show that the particle surface became rough due to the coating effect of CaCO3 crystals, and the pore spaces were reduced because of the partially filling effect of the crystals, which was responsible for the decrease in permeability and porosity. Furthermore, k fitted well with Cu and Cc, respectively, and the fitting curve reveals that larger Cu (Cu ≥ 6.0) and smaller Cc (2.0 > Cc > 0.5) were more suitable for MICP treatments and lead to a large reduction in permeability. The above results indicate that the grain gradation of calcareous sand had a significant influence on its permeability improved by MICP.

CHINA: THE STORY OF A MISSED OPPORTUNITY. HOW CHINA MANAGED TO DISREGARD THE SOUTH CHINA SEA RULING

On July 12, 2016 an international tribunal (registered with The Hague Permanent Court of Arbitration) ruled against China`s territorial claims in the South China Sea, arguing that the Chinese historic rights within the Nine Dash-Line map have no valid effect under the United Nations Convention on the Law of the Sea (UNCLOS). The tribunal’s decision came at a time when tensions in the South China Sea had reached a very high level amid increasing maritime incidents caused by China and the Chinese government’s construction of artificial islands in the open sea. What was supposed to be a major victory against China for the US-backed states (Vietnam, Philippines), turned out to be only a symbolic success for the Philippines. China not only rejected the sentence, but continued to conduct provocative naval exercises, harass other foreign ships and build artificial islands for military purposes. Using historical research and comparative analysis, this paper illustrates how China’s rejection of the ruling was facilitated by a number of legal, economic and political factors that have diminished international reactions and pressures on the Chinese government: the non-ratification of UNCLOS by the US, the lack of coercive mechanisms to enforce international rulings, the economic interdependence between China and other regional states and the precedents set by other major powers. Keywords: South China Sea, Permanent Court of Arbitration, UNCLOS, maritime claims, historic rights.

THE LEGALITY OF DENMARK’S ARTIFICIAL ISLAND (LYNETTEHOLM) IN INTERNATIONAL LAW OF THE SEA

The Danish parliament approved the construction of an artificial island called Lynetteholm, which aims to house 35,000 residents and protect the Port of Copenhagen from rising sea levels. Construction of Lynetteholm will take approximately 50 years, and the island will be 2.6 km2 in size. Since the regulation regarding Artificial Island can only be found in the United Nations Convention on Law of the Sea 1982 (UNCLOS 1982) which is not complete regulatory support along with no other regulations that can provide specifications regarding the implementation rules for the construction of an artificial island, both provisions and prohibitions in the process of making Artificial Island. This long-term development could cause a damage towards the marine life and cause air pollution in the construction area due to heavy trucks, change in the ocean currents in the Danish and Swedish oceans due to the size of the island, and cause potential changes to the territorial sea boundaries of Denmark’s EEZ. As long as the legal regulations regarding Artificial Island have not been made specifically and in detail, large-scale and long-term construction of artificial islands that cause legal problems will continue to occur in the future. Therefore, the making of special rules regarding Artificial Island has become a real urgency at this time. Denmark has an obligation to conduct a re-assess regarding problems that may arise as well as those that are contrary to UNCLOS.

Calming the Waters of the South China Sea: Solving Territorial Disputes over Artificial Islands

The South China Sea region has been a site of conflict for decades, with numerous states holding competing territorial claims due to its abundance of resources and strategic importance. Recently, China’s construction of artificial islands in the South China Sea has escalated tensions in the region and has strained efforts to bring peace. This paper observes the role of intergovernmental organizations such as the United Nations (UN) and the Association of South East Asian Nations (ASEAN) in resolving the conflict in the South China Sea. First, this paper studies the ASEAN-China code of conduct, the dispute management approach currently being negotiated between ASEAN and China. This code of conduct will govern the conduct of the countries involved in the South China Sea disputes. Furthermore, this paper proposes key provisions that should be incorporated into this code of conduct to make it more effective. Second, this paper reviews the conflicting views of ASEAN member states that impede the creation and adoption of the code of conduct. To conclude, this paper recommends an alternative solution through the United Nations Convention on the Law of the Sea (UNCLOS), proposing that the conciliation procedure provided in UNCLOS be adopted to resolve the long standing South China Sea disputes.

Can artificial ecological islands alter the biodiversity of macroinvertebrate? A case study in Fujin National Wetland Park, the Sanjiang Plain, China.

Many policies and studies globally have highlighted the pivotal role of wetland ecosystems regarding wetland biota and their ecological status. With the strengthening of wetland ecosystem management legislation and policy, wetland restoration should also consider increasing habitat diversity to improve biota. We explore whether the construction of artificial ecological islands can increase the diversity of and macroinvertebrates before assessing the effects of actively constructing islands via human intervention on wetland protection.We discuss changes in macroinvertebrate diversity (i) with and without islands, (ii) at different water‐level gradients surrounding the islands, (ⅲ) on different island substrates, and (ⅳ) at different time scales. We used ANOVA, ANOSIM, and cluster analysis to test the differences.The macroinvertebrate communities had spatially heterogeneous distributions which changes over time due to both natural and anthropogenic stresses. The establishment of islands significantly increased the community composition and biodiversity of the macroinvertebrate. Water depth and substrate affect community composition of macrozoobenthos. The abundance and diversity of macroinvertebrates can influence the biodiversity of their predators (fish and waterbirds). Potentially, the construction of islands could provide some cobenefits for the conservation of wetland fauna. Synthesis and applications. Establishing artificial ecological islands in broad open‐water areas and increasing water‐level gradient and substrate diversity can increase microhabitat availability and habitat heterogeneity. These changes can adapt to different ecological niches of aquatic organisms, increase biodiversity, and have a positive effect on the ecological restoration of inland freshwater marshes and wetlands.