Prioritization of HSE Management Risks in the Management of Construction Projects (Non-Mechanized Tunnel) by Monte Carlo Modeling Method

Given the extensive scope of construction operations, it's evident that construction activities rank among the leading causes of accidents in many countries. This underscores the critical need for in-depth research on health, safety, and environmental (HSE) issues within the construction industry. In this context, identifying and prioritising key indicators influencing non-mechanised tunnel construction accidents, particularly within high-risk construction projects, is a pivotal strategy to mitigate accidents and reduce the associated human and financial toll, thereby enhancing overall HSE conditions within the project. One noteworthy example of this imperative is the Tehran Shomal Freeway, a national mega project in Iran integral to the North–South Corridor initiative. Its initial phase comprises 39 tunnels spanning a total length of 31.5 kms, and it has encountered a multitude of HSE challenges, including tunnel collapses, landslides, and occupational accidents leading to fatalities. To gain insights into this complex scenario, a comprehensive approach was adopted. Initially, HSE experts' opinions on tunnel construction within the Tehran Shomal Freeway project were gathered through a structured questionnaire, employing the Delphi method to categorise these insights into 11 primary indicators and 74 sub-indices. Subsequently, a Monte Carlo modelling technique was applied, generating 2000 random data sets under the Skew Normal distribution. These data were then evaluated against three predefined success criteria and synthesised using the Copeland method to prioritise the leading indicators. Among the findings, it became apparent that “management” and “design and implementation” risks exerted the most substantial influence, while “Human Resources” risks had a relatively lower impact on HSE management within non-mechanised tunnel construction projects.