With the continuous improvement of construction management standards, thorough investigation into various management objectives becomes crucial. To address the current gaps in project management concerning time, cost, safety, and carbon emissions interrelationships, this study adopts the multi-objective optimization (MOP) theory and makes the following contributions: (1) proposes an innovative carbon emission model, which enhances the cost model by incorporating carbon cost factors, and establishes a MOP model covering time–cost–safety–carbon emissions; (2) validates the effectiveness of the proposed model and the feasibility of algorithms through empirical research and algorithm comparison analysis—the research demonstrates that NSGA-III exhibits significant advantages in solving MOP problems of this scale; (3) applies the entropy-weighted VIKOR method to objectively analyze the solution set obtained by NSGA-III for optimal solution selection. This study provides practical management tools for project managers and offers significant insights for researchers in construction management regarding multi-objective problem-solving and algorithm selection.

To conduct a more in-depth study on carbon emissions and influencing factors during the materialization stage of prefabricated buildings, this paper focused on a residential prefabricated building in Beijing. The LCA method, combined with BIM technology, was utilized to establish a process-based “LCA-BIM” carbon emission statistical platform and to propose a carbon emission calculation method. The carbon emissions during the materialization stage were calculated. The results revealed that the production of building materials contributed the highest proportion of carbon emissions, accounting for 85.73% of the total emissions during the materialization stage. Specifically, reinforcing steel and concrete dominated the overall carbon emissions from building materials, accounting for 97.44% of the total. Through a quantitative analysis in the process of carbon emissions calculation, the main factors influencing the carbon emissions during the production stage of building materials were identified. This study adopts a combined approach of empirical analysis and a literature review, establishing six basic hypotheses for four aspects: material selection, energy consumption, material storage, and carbon emissions in the production stage of building materials. A structural equation model was used to theoretically validate the influencing factors in the production stage of prefabricated building materials. SPSS27.0 and AMOS28 software were employed for data analysis. From the perspective of the overall impact, material selection had the strongest overall impact on the production stage of building materials, followed by energy consumption, while material storage had the smallest overall impact. From the perspective of direct impacts, energy consumption had the strongest direct impact on the carbon emissions in the production stage of the building materials. The findings of this study can provide a theoretical reference for national institutions and businesses for carbon emission evaluation and decision-making.

In foundation pit excavation, granite residual soil is frequently used as a foundation-bearing layer, necessitating the consideration of its unique engineering characteristics in stability studies. Numerical analysis is a crucial method for evaluating the stability of excavation pits, with the Modified Mohr–Coulomb (MMC) model showing good applicability. However, research on the MMC model in granite residual soil regions remains limited. This study investigates the impact of key stiffness parameters (\({E}_{ur}^{ref}\), \({E}_{oed}^{ref}\), and \({E}_{50}^{ref}\)) of the MMC model on the stability of excavation pit retaining structures, using case studies from the Zhuhai area. The research addresses the selection of stiffness parameters for different soil layers and proposes a proportional relationship between model stiffness parameters and field test mechanical parameters. Using the horizontal displacement of the underground diaphragm wall as an indicator, single-factor sensitivity analysis and orthogonal experimental methods were employed to determine the sensitivity and proportional relationships of stiffness parameters in the Zhuhai region. The findings indicate that \({E}_{ur}^{ref}\) has the most significant impact on model uncertainty, while \({E}_{50}^{ref}\) has the least effect on horizontal displacement. The ratios of \({E}_{ur}^{ref}\)/\({E}_{50}^{ref}\), \({E}_{oed}^{ref}\)/\({E}_{50}^{ref}\), and \({E}_{50}^{ref}\) to the deformation modulus (\({E}_{0}\)) provide essential references for numerical simulation of excavation pits in the Zhuhai area.

Against the backdrop of the ongoing implementation of the “dual-carbon” strategy and green building policies, this study concentrates on the production stage of precast concrete (PC) components. A composite analytical framework that integrates the structural equation model (SEM) with the system dynamics model (SD) is developed, through which a systematic and dynamically responsive model for the joint optimization of carbon emissions and costs is proposed. The results demonstrate that (1) when investment in green policies is maintained within the range of 10–20%, a 4.2% reduction in carbon emissions can be achieved by 2030, while costs remain optimized; (2) under the scenario of moderate green policy investment (10–20%) combined with a carbon tax of CNY 100/ton, carbon emissions can be reduced by 7.52%, with costs also reaching an optimal level; and (3) among the multi-path emission reduction strategies, the technology optimization pathway and energy structure optimization pathway achieve reductions of 9.68% and 8.97%, respectively. These findings provide theoretical support for the coordinated control of carbon emissions and costs during the production stage of PC components, while also offering empirical evidence and practical guidance for governments in formulating green building policies and for enterprises in advancing low-carbon transitions.