Markus Scheffer

Evaluation of Disturbances in Mechanized Tunneling Using Process Simulation

Production in mechanized tunneling frequently encounters disruptions due to sensitive process interdependencies. Reasons can be technical failures, insufficient capacity dimensioning, organizational deficiencies, or sensitive supply chains. These unproductive times could be reduced by an adequately designed project setup including logistical aspects. Therefore, possible disturbances must be identified and analyzed in detail. Based on this investigation, the machine and logistics setup can be changed to cope with unforeseen events. We present a modeling and simulation approach to analyze production and logistic processes of mechanized tunneling processes in a transparent and understandable way. The system is formalized in the modeling standard SysML. Thereby, we consider relevant system elements and process interdependencies to assess the effect of disturbances and to identify bottlenecks. We distinguish three kinds of disruptions: i technical failure of main elements related to the production processes, ii issues resulting from an insufficient supply chain, and iii cascading disturbances. The implementation in a simulation environment and the processing of relevant input data are presented hereupon. The presented approach is then illustrated by means of an application example based on a completed metro project. Three extending simulation studies quantify the impact of the identified disturbance categories.

Simulation-Based Analysis of Integrated Production and Jobsite Logistics in Mechanized Tunneling

The planning of jobsite layouts and logistics management has a major impact on the performance of tunnel construction projects that use tunnel-boring machines (TBMs). Frequently, projects do not reach the highest possible production performance due to undersized logistics processes or insufficient storage capacities. In this paper, a flexible simulation framework for analyzing interactions between production and logistics processes on tunneling jobsites is presented. A formal ontology for logistic elements on a tunneling jobsite is developed using SysML formalism. Based on this formulation, single systems elements combined in process chains are analyzed and their influence on production processes is evaluated. The formal system description identifies process dependencies and resource constraints of the system elements. These formulations are implemented in configurable simulation components for construction equipment, storage spaces, and production materials. Using these components, a jobsite simulation model can be created. The jobsite layout is represented at a high level of detail, with geometric shapes used for estimating storage capacities and movement durations. This approach uses discrete event and system dynamic simulation and applies probability functions to inputs representing production process times. Dynamic simulation can reveal unknown impacts of logistical processes on the continuous advance processes of the TBM. A simulation model for TBMs is integrated to determine the demand for supply processes. A fast and effective comparison between different jobsite layouts and logistics strategies is possible due to flexible components. By analyzing the workload of construction equipment, robust and efficient setups can be developed. A case study illustrates the usefulness of the simulation framework by comparing the performance of three different jobsite setups for a tunneling project.

Assessing maintenance strategies for cutting tool replacements in mechanized tunneling using process simulation

In mechanized tunneling, detailed planning with an accurate performance prediction of the tunnel boring machine (TBM) is needed for a successful tunnel project. Undersized logistical components, disturbances of the supply chain, as well as negligence of maintenance schedules reduce the TBM performance and frequently lead to avoidable times of standstill. This paper presents a performance forecast model for mechanized tunneling projects focusing on wear and maintenance processes of the cutting tools. The developed simulation model has been implemented in the simulation environment AnyLogic using the multi-method approach, including agent-based modeling as well as discrete-event and system dynamic simulation. The model can be used to evaluate different maintenance strategies for a tunneling project. Thus, an improved maintenance strategy for reducing the time of standstill can be found.

Simulation-Based Analysis of Surface Jobsite Logistics in Mechanized Tunneling

The construction procedure in mechanized tunneling is affected by a complex interaction of logistic processes. Due to restrictive factors (like limited space on construction sites), a just-in-time delivery of material is required for production purposes. Slight differences of the production rate of a Tunnel Boring Machine (TBM) have huge impacts at the logistical chain. Therefore, logistic management is one of the key factors responsible for the success and profitability of tunneling projects. In this paper, a discrete event simulation model is presented that supports tunneling experts in the planning process and can be applied in the construction phase as a tool for decision analysis. Since each TBM is unique, it has a unique demand for logistic solutions. Therefore, the simulation model is implemented in a modular manner such that it can be applied to a vast number of different projects in mechanized tunneling. The properties of the construction site and the TBM are freely configurable. To show the functionality of the model, a fictive demonstration model was conducted. It illustrates the influence of different logistic processes on the production rate of a TBM as well as the complex interactions of single logistic processes in the supply chain of a construction site.

Jobsite logistic simulation in mechanized tunneling

Projects in mechanized tunneling frequently do not reach their targeted production performance. Reasons are often related to an undersized or disturbed supply-chain management of the surface jobsite. Due to the sensitive interaction of production and logistic processes, planning and analyzing the supply-chain is a challenging task. Transparent evaluation of chosen logistic strategies or project setups can be achieved by application of process simulation. This paper presents the continued work of a simulation approach to analyze the complex system of mechanized tunneling. Special focus of this publication lies on the internal logistic as a part of the jobsite supply-chain. The generic implementation allows a flexible configuration of jobsite elements to compare possible setups. A case study demonstrates the approach and highlights the sensitive interaction of production and logistic processes under the influence of disturbances. Additionally, improvements to the original setup of the case studys construction equipment can be derived.

Simulation of maintenance strategies in mechanized tunneling

Mechanized tunneling is one of the most common methods used for underground constructions for infrastructure systems. Since a tunnel boring machine (TBM) represents a non-redundant single machine system, the efficiency of maintenance work highly impacts the overall project performance. The wear and tear of cutting tools is a critical, but mostly unknown process. To plan the maintenance work of cutting tools efficiently, it is necessary to know the current tool conditions and adapt the planned maintenance strategies to the actual status accordingly. In this paper, an existing theoretical empiric surrogate model to describe cutting tool conditions will be used and implemented as a software component within a process simulation tool that manages TBM steering parameters. Further, different maintenance setups for TBM cutting tools are presented and evaluated. To prove the capability of the presented approach, a case study will show the effects that improved maintenance work can have on project performance.

BIM Project Management

Building Information Modeling (BIM) is characterized by a well-structured creation and exchange of information. In the last years, the term has also been referred to as “Better Information Management”. Due to the high amount of involved parties, which by nature hold contradicting views and interests, the organization of information requirements represents a key factor in the context of project management. The major challenge and chance, lies in improved project and information management achieved by applying BIM and thus, producing and using high-quality information. This chapter presents roles and perspectives to be considered in the building life cycle. Information Requirements and related Information Models are introduced to organize the resulting production of information and its exchange during different project stages. The concept is based on the methodology presented in ISO 19650.