Simulation applicationsfor efficiency in tunnel constructions

Abstract

In large and complex construction projects that consume a variety of resources, the efficient use of resources is the hinge of planning and control. However, in many countries and in Turkey, planning, control and efficiency have been attempted through previous experience and very simple mathematical modeling. Integration of these attempts with the project schedule is rare and many large construction projects have been completed with overruns. Overruns can be the result of various reasons such as communication problems, uncertainties, wrong decisions, low productivity rates, inadequate planning and lack of technology. This thesis is based on real field observations and practices that aim to simulate repetitive construction operations at different five construction sites and evaluate the results, focusing on the relationship between lean construction and simulation. The EZStrobe simulation tool and AnyLogic software, which are capable of modeling moderately complex processes, were used instead of advanced simulation tools. Five different cases were studied in this paper. Four of them were previously completed without the use of simulation methodology. These cases are different projects in İstanbul and cases focused on a pipe jacking project, a dry batch and a delivery placement operation, two of them are related to tunneling projects with New Australian Tunneling Method (NATM). The aim of studying these four cases is to answer the question "What could happen if simulation methodology is used before construction starts? " The fifth case is related to the lining works of the New Australian Tunneling Method (NATM) tunnelling project. In this case, the simulation methodology was applied to see the result that the crew members and equipment are sufficient to complete the lining works within the approved schedule. The simulation methodology was used prior to the start of lining works in associated areas. Data was collected from authorised people on site. This simulation was first modelled using the EzStrobe simulation tool. A sensitivity analysis was then carried out to obtain the optimum result. Then AnyLogic software is used for modelling to compare the results. After that, Monte Carlo analysis was applied to ensure more reliable result and obtained timing values integrated both simulation software EzStrobe and AnyLogic. On the other hand, simulation models are created as flexible to be able to easily changeable. The study shows that; real-time projects can be simulated with different parameters at the beginning of the project to evaluate the productivity of resources; in projects that have started and/or are in progress and/or will start, by using the simulation system, resources can be used correctly and efficiently to minimize waste, or the most appropriate decisions can be made about their use. In conclusion, construction operations can be implemented with less resources, low cost and cycle time, and high productivity with simulation models.