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Mega construction projects (MCPs) have long periods, complicated environments, a multiplicity of mechanical equipment and personnel, and a large number of safety risk factors on sites. The different safety risk factors of MCPs have coupling effects among them, which can produce new risks and even lead to an accident. These factors present a major challenge for project managers to take on risk management in MCPs. Although previous research has done much work on risk factor identification and control in MCPs, less attention has been given to the coupling effects among risk factors, which affect the identification effect of key safety risk factors and their coupling paths. To compensate for this gap, this research used the latent Dirichlet allocation (LDA) topic model to identify risk factors in mass accident reports, the N-K model to calculate the coupled style, and then coupled the N-K model and the social network analysis (SNA) model to identify the safety risk factors and determine the coupling paths in MCPs. The results reveal the following: (1) six first-level subsystems are identified, and there are 31 second-level safety risk factors included in MCPs; (2) H1 (low safety awareness), H2 (CAT operation), H6 (improper safety protection measures), P4 (improper safety supervisors), P5 (imperfect management system), S3 (owner's mistakes), and M2 (improper maintenance of equipment) are the key safety risk factors in MCPs; and (3) unfavorable environmental factors can easily lead to the emergence of the multirisk coupling of G-S-P-H-M-E , which should be carried out by special management. This research provides a reference for the identification and control of safety risks in MCPs and contributes to the development of complex system risk management and control research. [ABSTRACT FROM AUTHOR]

Engineering change (EC) risk may negatively impact project schedule, cost, quality, and stakeholder satisfaction. However, existing methods for managing EC risk have certain shortcomings in evidence selection and do not adequately consider the quality and reliability of evidence associated with EC risks. Evidence grading plays a crucial role in ensuring the reliability of decisions related to EC risks and can provide essential scientific and reliability support for decision-making. In order to explore the potential risks associated with architectural engineering changes (ECs) and identify the most significant ones, this study proposed a methodology that combines evidence grading theory and Latent Dirichlet Allocation (LDA) topic analysis means. Initially, the evidence-based grading theory served as the creation of a grading table for evidence sources related to EC risk. Specifically, we categorized the evidence sources into three levels based on their credibility. Subsequently, we selected evidence with higher credibility levels for textual analysis, utilizing the LDA topic model. This involved analyzing regulations, industry standards, and judgment documents related to EC, ultimately identifying the themes associated with EC risks. In addition, by combining EC risk topics with relevant literature, we identified factors influencing EC risks. Subsequently, we designed an expert survey questionnaire to determine the key risks and important risk topics associated with potential risks. The results show that by synthesizing information from both Class A and B evidence, a total of five prominent risk themes were identified, namely contract, technology, funds, personnel, and other hazards. Among them, the technical risk has the highest value, so it implies that the risk is the most important, and the key risks are engineering design defects, errors, and omissions. [ABSTRACT FROM AUTHOR]

Much energy is dissipated when large equipment moves slowly. Generally, equipment scheduling at construction site is supposed to minimize equipment slowdown and deadhead moving. Table methods are always adopted to optimize transfer sequence, but the feasible solution is well disappointing. For the acceptable solution relevant to task points in construction equipment scheduling, transfer table is divided into four regions. After proper augmentation and deflation, the acceptable solution evolves into global coordinating solution of construction scheduling, which contributes to minimizing slowdown and deadhead mileages. This method has been verified in practical engineering and is a significant reference on decision making of construction equipment scheduling.