Study On Construction Schedule Simulation And Multiple Attribute Decision Making For Concrete Gravity Dam

The construction process and construction quality of the concrete gravity dam always exert great impact on the duration and safety of the whole project.However,the complicated geological contexts and limited space resources of the gravity dam sites can go against the construction layout and transportation.Therefore,it is currently faced important issues that how to comprehensively consider various factors influencing the construction of gravity dam,and how to optimize and compare several different construction schemes to choose the best one.Meanwhile,there are higher requirements of the real-time prediction accuracy of the future construction schedule.This paper studies and develops the multi-attribute decision-making and dynamic VIKOR extension methods based on the concrete gravity dam construction simulation model,and the research results are illustrated as follows:1.Considering the problem that the sample data is deficient in quantity for the real-time updating of concrete gravity dam construction simulation parameter,a construction parameter updating method coupling the improved random weighting method and the Bayesian method is proposed,and the parameter Bayesian real-time updating under the condition of small sample is realized.The construction of concrete gravity dam is a complicated random dynamic process which is difficult to describe by simple analytical mathematical models.With the rapid progress of computer and simulation technology,it is possible to dynamic simulate the construction of concrete gravity dam on computers In the simulation process,the selection of construction parameters has great influence on the rationality and scientificity of the simulation results.Most existing research models choose the construction parameters based on construction experiences or the reference of similar projects.The possible large gap between different projects may lead to the distortion of the simulation results.It is one of the hotspots to research the parameter updating of the simulation model according to the real-time construction information under the priori distribution.The parameter updating of construction simulation models requires a large amount of construction data.However,it is unrealistic to record all the data of the concrete gravity dam construction under the existing technical conditions and cost constraints.Therefore,how to obtain more accurate posterior distributions based on limited site sample information becomes a practical problem.In order to solve this problem,this paper proposes a construction parameter updating method coupling the improved random weighting method and the Bayesian method,and realizes the distribution estimation of simulation parameters in the case of small samples.Firstly,the small samples of construction data obtained in construction sites are extended to large samples based on the improved random weighting method,and parameter estimation is calculated to approximate the real distribution.Then the parameter distribution is updated in real-time by the Bayesian method.Finally,based on the aforementioned model,the construction simulation parameter updating and the construction schedule prediction are realized in real-time under the condition of small sample.2.Considering the problem that the current multi-attribute decision-making methods of concrete gravity dam construction generally lack the consideration of the variation of evaluation indexes and their weights in dynamic conditions,the dynamic VIKOR extension method for multi-attribute decision-making is proposed,which is applicable to the concrete gravity dam construction characteristics of long duration and complicated process.It is a necessary work in the design stage to compare different dam pouring schemes according to the whole-process construction simulation results of concrete gravity dams,which affects whether the whole project can be accomplished in the target quality and time and even determines the engineering safety to some extent.However,existing multi-attribute decision-making methods mostly focus on the whole construction process,and seldom consider the modification of model indexes and their weights in the dam construction process.So it is necessary to analyze the indexes of different schemes in different dam construction stages to realize a more refined and reliable scheme evaluation and optimization.The dynamic VIKOR extension method is introduced in this paper,and the construction process is divided into several stages according to the construction organization design and the construction simulation results.Then,different weights are assigned to the indexes in different stages with the consideration of real construction factors,and the performance of each scheme in every stage is quantified and analyzed to carry out comprehensive evaluation.Finally,a case study of a specific project is demonstrated and the optimal solution reached by the dynamic VIKOR extension method is proved to better reflect the implementation performance of the construction schemes,which can provide more reliable information for the decision makers and build scientific basis for multi-attribute decision-making of concrete gravity dam construction.