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With the continuous growth of urban development, ocean resource exploitation and tourism demands, the construction of artificial islands has become increasingly important. Traditional methods for constructiing artificial islands mainly include non-cofferdam reclamation and cofferdam-based wet reclamation. However, these methods have several problems: the ground treatment lacks systematic reinforcement measures, which can easily lead to significant settlement; the construction process of backfill materials is prone to disturbing the marine environment, affecting water quality and the ecosystem; and there are repetitive excavation procedures in subsequent engineering construction, increasing the workload and costs. To address these issues, a synchronous construction method, namely dry reclamation with cofferdam, is proposed for building artificial-island cities. The specific procedures of this method are as follows: cofferdams are constructed facing each other on the outer sides of the designated area, while offshore cement-soil mixing piles are used to reinforce the ground in the filling area; after the cofferdam is completed, seawater is pumped out and a cushion layer is evenly laid on the original seabed; building pile foundation are then constructed, followed by the installation of prefabricated underground structures such as tunnels, pipe galleries, and basements at the bottom elevation. Simultaneously, soil backfilling is carried out layer by layer. This process is repeated structural construction and soil backfilling until the backfill reaches the specified elevation. The synchronous construction method can reduce the amount of filling material and the cost of re-excavation, which can greatly shorten the construction period and lower overall costs, and reduce environmental pollution during the reclamation process. The research results can provide a new option and reference for construction of large-scale artificial islands.

Carbon emission reduction in the construction industry is crucial for promoting low-carbon transformation of the industry and for realizing the carbon peaking and carbon neutrality goals. This study analyzes the current status of carbon emissions in Chinese construction industry. It identifies that the production of building materials and the operation of buildings are the primary sources of carbon emissions in the overall construction process. Moreover, the growth rate of carbon emissions from the construction industry in China is decelerating, and the spatial characteristics of carbon emissions demonstrate an increase from the south to the north and from the west to the east. We have identified six key challenges that must be addressed to achieve carbon peaking and carbon neutrality in the construction industry of China: policy and standards framework, energy-efficient and carbon-reducing technologies, reduction of carbon emissions from existing buildings, carbon emission data collection and monitoring systems, economic incentives, and increased awareness of carbon reduction. Staged goals for the low-carbon development of the construction industry are also proposed. Furthermore, we suggest improving related policies and standards system, optimizing the use of energy-saving technologies, reducing carbon emissions in existing buildings, developing green finance, improving the ability to monitor carbon emissions, and enhancing the awareness of energy conservation and carbon reduction, so as to provide references for the low-carbon transformation and high-quality development of China’s construction industry.

Underground space and resources are crucial for solving energy, resource, and living space problems faced by mankind. Shafts are throats that extend from the ground into the strata and thus require safe, efficient, green, and intelligent construction. In this paper, we analyze the need and necessity for developing large-diameter drilling technology and equipment, examine the development status in China and abroad, and analyze the challenges faced by China from the perspectives of basic research, applied technology development, high-end equipment manufacturing, and project demonstration. Moreover, we pinpoint the development directions of shaft construction technology and equipment and propose that China should establish the development concept of intelligent drilling, clarify the development path and tasks of intelligent drilling, establish relevant standards and specifications of large-diameter drilling, and promote the construction of intelligent drilling platforms and demonstration projects, thereby providing support for shaft construction in fields such as mining, hydropower, transportation, and urban construction.