Construction Schedule Risk Analysis Of High Roller Compacted Concrete Dam Based On Improved CSRAM

There are some problems existing in the construction of high RCC(rolling compacted concrete) dam. Not only the construction period is long and application technology is complicated, but also multiple risk factors exist in every construction links such as concrete producing, transporting and dam works. The factors include weather condition, aggregate supply, concrete production, formwork assembling and dismantling, efficiency of transport machinery and dam surface machinery, road condition, proficiency of workers, construction complexity and organization and coordination. Because of these existed risk factors, the dam construction usually cannot be finished as the planed schedule. The schedule delay not only raises the cost, but also cause some quality problems. Therefore, it is important to establish a comprehensive, accurate and objective schedule risk analysis model. The accurate analysis results can provide theoretical basis of dam construction schedule risk for the designers to analysis and judge accurately.Most of traditional schedule risk analysis methods only pay attention to simulation of construction period and calculation of completion probability, and seldom make uncertainty analysis of risk factors at the same time. In addition, present models don't consider law of risk factors' variation with construction period, which affects the accuracy of schedule risk analysis. Firstly, use WBS-RBS method to distinguish the risk factors which influence the RCC dam construction schedule, and estimate the degree of risk event. Secondly, a mathematical model called improved CSRAM(Correlated Schedule Risk Analysis Model) is proposed in this paper, which is based on traditional CSRAM model. This model not only takes the construction feature of high RCC dam into account by divide the dam construction project into some divided works and unit works, but also considers the law of risk factors' stochastic variations with construction schedule and their comprehensive effect on construction schedule. Using Monte Carlo method to solve this model, develops a RCC dam construction schedule simulation and risk analysis system, and completion probability of high RCC dam's plan time is obtained and uncertainty analysis of risk factors is able to be achieved with insuring the comprehensiveness, accuracy and objectivity of results. The results of engineering case show that, when compared with traditional CSRAM, completion probability obtained by improved CSRAM is higher and distribution of simulation period is more convergent. The analysis results of improved CSRAM are more accurate and closer to the actual engineering condition. In addition, among the ten risk factors selected by this paper, efficiency of dam surface machinery and proficiency of workers have the maximum uncertainty.