Modelling and simulation of the block pouring construction system considering spatial-temporal conflict of construction machinery in arch dams.

The spatial-temporal conflicts in the construction process may cause a series of construction quality, safety and schedule problems. The outbreak of mechanical spatial-temporal conflict in the construction process of the arch dam pouring block is random and uncertain. Scientific simulation and preview of the pouring construction process and analysis of the level, time, and influence degree of the outbreak of spatial-temporal conflict are significant means to optimize the construction organization and management. According to the degree of spatial-temporal conflict and its effect on security and efficiency, the subsidiary space scope of construction machinery is divided into three levels from inside to outside. The quantification algorithm of spatial-temporal conflict is proposed based on the three-layered space and time-space microelement model. The discrete system theory is employed to develop a simulation framework that systematically incorporates four core components: simulation objectives, construction machinery operational cycles, resource allocation mechanisms, and modeling assumptions. Combined with the typical pouring block in Baihetan arch dam, the construction process is simulated and the visualization system is developed, which achieves the information integration such as the quantification of the spatial-temporal conflict, the analysis of the influence effects, and the visualization of conflict information. The system simulation results show that the spatial-temporal conflict problem always exists in the pouring construction process, the problems of security risk and efficiency loss are inevitable. And the reasonable unloading point planning and mechanical trajectory setting can effectively reduce the risk of spatial-temporal conflict. Those studies provide a reference for the rational organization and scientific decision-making of pouring construction activities, and new ideas and methods for the safe and efficient construction, as well as the scientific and refined management, of arch dams.