# Safety Assessment of Gas Pipelines Crossing River through Hydrodynamic Analysis
## 1 Introduction
Studies have analyzed the risk factors of pipelines crossing rivers in urban environments and presented complex risk assessment systems that consider the interaction between urban infrastructure and the natural environment [10]. Previous studies take into account the various variables necessary to maintain the structural stability of pipelines, emphasizing the essential need for preparedness against natural disasters like floods and scour. Similarly, fatigue analysis and lateral stability evaluation methods for pipelines exposed due to river scour have been proposed, demonstrating through actual case studies that these risks can indeed occur [20]. This research provides clear evidence of how significantly pipeline exposure due to scour can impact long-term operations and offers practical alternatives necessary to maintain the stability of exposed pipelines. Additionally, scour prevention measures utilizing soil bio-engineering have been suggested, introducing sustainable methods to effectively manage scour at pipeline crossing sections [21]. This approach supports an ecological method to ensure the long-term safety of pipelines through plant-based stabilization techniques. Furthermore, important tools for predicting and preparing for future scour risks have been developed by forecasting the scour depth of river-crossing pipelines using Support Vector Machines (SVMs) [22]. Such predictive models can contribute to maintaining pipeline safety and preventing potential accidents. Using numerical analysis techniques to assess the safety of gas pipelines crossing rivers plays a crucial role in maintaining the stability of pipeline structures and predicting risk factors. Related studies quantitatively analyze the physical changes in gas pipelines and deformation due to external pressure, identifying the effects of various environmental factors on pipeline performance. For instance, some researchers focus on the buckling mechanisms of marine pipelines, explaining their physical deformation and suggesting methods to prevent pipeline failure due to buckling [23]. This research provides important data for identifying structural problems in gas pipelines. Other studies have addressed the effect of the pipeline arrangement on scour and flow velocity fields, analyzing in detail how pipeline arrangement impacts the scour process [24]. These studies present methods for evaluating pipeline safety using numerical analysis techniques and offer useful information for predicting the scour risk of gas pipelines crossing rivers. Additionally, analyses of the stress and deformation of buried gas pipelines exposed to buoyancy forces in liquefaction zones provide insights into how gas pipelines respond to various external forces, suggesting factors to consider for the safe design of pipelines [25]. Further research has evaluated the ability of corroded steel pipes to withstand compressive forces using nonlinear analysis after reinforcing them with FRP casing grouting [26]. This work provides important data on enhancing the structural stability of corroded pipelines, contributing to the development of pipeline maintenance plans. Studies have also analyzed how buried composite pipelines respond to stresses caused by fault movement, providing specific considerations when designing pipelines to withstand natural disasters such as earthquakes [27; 28]. These previous studies offer valuable information for assessing the safety of gas pipelines crossing rivers using numerical analysis techniques. Through a quantitative analysis that accounts for the physical characteristics of pipelines, external pressure, and environmental factors, a foundation is established for predicting and addressing the various problems that may arise in pipeline design and maintenance. Analysis results using numerical analysis techniques have shown that the burial depth of gas pipelines buried in rivers significantly influences their stability.