ESPN-Based Analysis on Schedule Risk in Rockfill Dam Construction

摘要

To sciencifically arange the schedule and keep the schedule risks under proper control is among those most important tasks which ensure a rapid and economic construction of the rockfill dam.In consideration of the shortcomoings of the network planning based schedule risk analysis for a complex system,such as the rockfill dam construction system with multiple phases,multiple asynchronous and/or concurrent tasks,this paper presents an ESPN(extended stochastic Petri net)-based schedule risk analysis for the rockfill dam construction.With the ESPN-based method,it is possible to simulate the structure of the construction system and the construction processes more realistically,to consider the stochastic characteristics of process times and construction conditions,and to consider the combination of risk factors and their acting time more accurately. Through the simulation of the whole construction process,not only the distribution of the time for completion of the project,but also the distribution of time for completion of key tasks can be obtained.Based on which the risks in scheduling the whole project and the risks in scheduling the key tasks can be estimated,and the bottleneck in the schedule can be found.In addition,different construction schemes can be compared. This paper also presents the method of building the ESPN model using structured and object-oriented programming and a reference model for simulating the construction process with multi-phases and concurrent tasks.