Analysis of microtunnelling construction operations using process simulation

Microtunnelling operations involve a complex interaction of processes that require a variety of supporting equipment and personal experience. Furthermore, different construction processes such as supply chain management for the machine or for material handling must be integrated. Breakdowns of critical processes will directly affect the performance of the construction, with impacts on extended construction time, increased cost as well as reduced productivity of the microtunnelling project. If the construction process is reasonably planned, the construction operations may be controlled and adjusted more efficiently. The use of operational process simulation can be a benefit for planning and operating a microtunnelling project. Thereby, problems at different construction phases can be anticipated and analyzed. Moreover, it has potential to optimize usage of resources, to develop better project plans, to minimize costs or project duration, to improve overall construction project management and to avoid costly mistakes. This thesis presents an approach for analyzing construction operations with micro tunnel boring machines (MTBM) utilizing process simulation. The goal is to develop an appropriate and adaptable simulation module for microtunnelling construction operations. It helps to analyze the processes and to identify the factors, which influence the operation productivity of the construction process essentially. In addition, the influence of different soil conditions and of disturbances on the productivity of microtunnelling operations have to be determined. In view of these objectives, a System Modeling Language (SysML) model describing the microtunnelling process is developed in the first step. The simulation model consists of three types of diagram: block definition diagram (bdd), state machine diagram (stm) and sequence diagram (sd), which are supported in the SysML. The simulation model is used to analyze and understand the entire process involved in microtunnelling construction and identify the model variables for which information needs to be collected. Subsequently, the simulation software AnyLogic is applied to create the MiSAS (Microtunnelling: Statistics, Analysis and Simulation) simulation module based on the SysML formalization. The implementation of the proposed methodologies, utilizes discrete event simulation (DES) and system dynamic (SD) modelling. Three actual microtunnelling projects at the city of Recklinghausen, Germany, are used for the validation of the developed simulation module. After validation, the simulation module is expanded with considerations of different soil compositions and disturbances of operations. The simulation module allows to evaluate the impact of the different ground conditions, disturbances and predict the resulting tunnel advance rate. Further, the impact of varying resources on the MTBM advance rate is studied in a sensitivity analysis.