The earthmoving industry in the UK is described with reference to the major changes in emphasis over the past few decades. The sites that were chosen for study are described and the method of data collection outlined. A determinate model is developed. This is solved using a spreadsheet and the term match factor, indicating the efficiency of an earthmoving operation, is introduced. The disadvantages of the determinate model are discussed with the main conclusion that the variability in the earthmoving plant's working rates means that the production cannot be calculated accurately by determinate methods. A model is then developed based on the discrete-event models used to evaluate queuing systems. This model was initially tested on a computer spreadsheet but a dedicated program, in C, was later written. Discrete-event simulation requires the generation of random numbers and emphasis is placed on the determination of the probability distributions that accurately represent the real distributions of plant cycle times. A three stage validation process was used which involved both the acceptance from 'experts' of the modelled system (which was obtained both in the UK and the United States) and also the ability of the model to determine accurately the production of observed operations. The simulation model could then, once validated, be used as an experimental platform. Experiments on actual operations have indicated which of the input factors to an operation the output is most sensitive to. They have shown that the correct number of trucks and maximisation of the loader working rate is essential of efficient earthmoving.
|Smith, Simon D.
|University of Edinburgh
|Electronic Thesis or Dissertation
Page generated in 0.0019 seconds