Study On Construction Simulation And Optimization For The Underground Powerhouse System Of Xiangjiaba Hydropower Station

For the large capacity of generating unit, wide span and high side of grottoes, and concentrated collocation of underground structures, the underground powerhouse system construction of Xiangjiaba hydropower station is a very complicated process. The working procedures are interfered by each other and many influencing factors should be considered during the construction process. With traditional calculating and analyzing methods, it is difficult to get optimal mechanical equipment allocation and reasonable construction scheduling. In this paper, a new methodology of construction simulation for Xiangjiaba underground powerhouse system is presented, which combines object-oriented simulation modeling, cyclic operation simulation, dynamic simulation, network optimization and GIS-based 3D visualization. The main research contents and achievements are summarized as follows:(1) Based on the system analysis for underground powerhouse construction of Xiangjiaba hydropower station, a hierarchic and modular modeling method is presented. The simulation modeling course is expatiated and the approach to determine model parameters to evaluate its sensitivity is discussed.(2) Cooperating closely with the construction organization design work, the author carries out in-depth research on construction simulation and schedule optimization for Xiangjiaba underground powerhouse system. Moreover, methods of mechanical equipment coordination and resource optimization with dependence relationships among activities are discussed. The simulation results are analyzed to get much important information such as feasible construction period, reasonable construction scheduling, critical path, and optimal construction intensity.(3) A simulation-based analysis method with flexible network planning is presented and a breakthrough is made on the limitation of conventional PERT. The project completion probability is discussed, and which fully describes the uncertainty of construction scheduling and provides good basis for time limit analysis.(4) By using the powerful graphic processing techniques of GIS, the complicated construction process can be described vividly with dynamic digital three-dimensional pictures and the 3D dynamic visualization for construction of Xiangjiaba underground powerhouse system is realized, which provides an effective means for grasping the construction process comprehensively and quickly. (5) According to the presented ideas and the construction peculiarity of Xiangjiaba project, the author develops software of construction simulation and optimization for underground powerhouse system of Xiangjiaba hydropower station (ESAS-XJB), which provides a powerful analysis tool for construction system analysis research of underground powerhouse system.