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Špačková, O (2012) Risk management of tunnel construction projects, Unpublished PhD Thesis, , Czech Technical University.

  • Type: Thesis
  • Keywords: construction delay; failure; uncertainty; construction cost; construction project; tunnel; excavation; infrastructure project; organizational factors; risk management; Czech Republic; probability; statistical analysis; case study
  • ISBN/ISSN:
  • URL: https://www.proquest.com/docview/2674875671
  • Abstract:

    Estimates of uncertainties and risks of the construction process are essential information for decision-making in infrastructure projects. The construction process is affected by different types of uncertainties. We can distinguish between the common variability of the construction process and the uncertainty on occurrence of extraordinary events, also denoted as failures of the construction process. In tunnel construction, a significant part of the uncertainty results from the unknown geotechnical conditions. The construction performance is further influenced by human and organizational factors, whose effect is not known in advance. All these uncertainties should be taken into account when modelling the uncertainty and risk of the tunnel construction.For reliable predictions, it is essential to realistically estimate the parameters of the probabilistic model. At present, such estimates mostly rely on expert judgement. However, these can be strongly biased and unreliable. Therefore, the expert estimates should be supported by analysis of data from previous projects.This thesis attempts to address these issues. First, it introduces a simple probabilistic model for the estimation of the delay due to occurrence of construction failures. The model is applied to a case study, which demonstrates, how the probabilistic estimate of construction delay can be used for assessing the risk and for making decisions.Second, advanced model including both the common variability and construction failures using Dynamic Bayesian Networks (DBNs) is presented. This model takes over some modelling procedures from existing models but it extends the scope of the modelled uncertainties. The model is applied to two case studies for the estimation of tunnel construction time. It is demonstrated, how observations from the tunnel construction process can be included to continuously update the prediction of excavation time.Third, an efficient algorithm for the evaluation of the proposed DBN is developed. A modification to the existing Frontier algorithm is suggested, denoted as modified Frontier algorithm. This new algorithm is efficient for evaluating DBNs with cumulative variables.Fourth, performance data from tunnels constructed in the past are analysed. The data motivates the development of a novel combined probability distribution to describe the excavation performance. In addition, the probability of construction failure and the delay caused by such failures is estimated using databases available in the literature. Additionally, a brief database of tunnel projects and tunnel construction failures from the Czech Republic is compiled. The database includes basic information on all tunnels, which have been constructed in the Czech Republic since 1989. The database of failures, which occurred in the analysed tunnels, contains 17 events, mostly cave-in collapses.The models presented in this thesis are applied to the estimation of tunnel construction time. The construction costs can be assessed analogously by replacing the time variables with cost variables. The costs can also be modelled as a function of the construction time.The statistical analysis of data presented in the thesis provides a valuable input for probabilistic prediction of construction time in infrastructure projects. The results of the case studies seem to realistically reflect the uncertainty of the construction time estimates.

Ahmed, S S (2018) Innovation of building processes in Syria by using BIM, Unpublished PhD Thesis, , Czech Technical University.

Petlíková, K (2021) Application of biological algorithms in standardization of construction work, Unpublished PhD Thesis, , Czech Technical University.

Vyčítal, M (2019) On BIM based automatized nD modelling for construction management, Unpublished PhD Thesis, , Czech Technical University.