current research

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Current Research



Development of an innovative separation method of used bentonite suspensions for economi-cally beneficial, resource-efficient and environmentally compatible disposal - Phase II

Aim of the research project is to improve or replace nowadays separation processes by adapting a new electrochemical separation process, the ‘electrocoagulation’, where no additional agents are necessary and incorporating it into a new developed processing system.
The findings of the Phase I are the start point for the development of an industrial prototype in Phase II.

Contact persons:
Dr.-Ing. Britta Schößer
Ivan Popovic, M.Sc.

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Method for costing of road tunnels

The cost estimation of tunnel construction is subject to numerous uncertainties that can result in deviations between the predicted and real costs. There is no up-to-date model to estimate the costs of a tunnel structure. Within this Research Projekt methods for more precise cost estimate or cost calculation are developed on the basis of an analysis of the construction costs of recent road tunnel projects.



Contact persons:
Dr.-Ing. Götz Vollmann
Peter Hoffmann, M.Eng.
Dipl.-Ökonom Hans Adden

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U-Threat

In large cities and metropolitan areas, metro networks are of particular importance because they are unaffected by traffic congestion on the roads. This independence and the short journey times make the underground even more popular. In Berlin, for example, the number of passengers increased from 2008 to 2015 by almost 20 % to more than half a billion passengers per year.
However, diverse threats and incidents can lead to great impairments of the underground transport. A few possible scenarios are bomb threats, flooding, fires and gun rampages. For this reason it is necessary to further improve the resilience – resistance against damaging effects – of underground public transport systems.
In the U-THREAT project, concepts and technical solutions are being produced, firstly to run degraded mobility mode quickly after an incident, and then be able to return to normal operation. The basis is an evaluation scheme to determine the vulnerability of sections of a metro network and individual stations. Then measures will be prepared in order to improve the resilience of all the significant areas.

Contact persons:
Dr.-Ing. Götz Vollmann
Peter Hoffmann, M.Eng.

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Collaborative Research Center 837: Interaction Modeling in Mechanized Tunneling



Subproject A4: Modelling of the conditioned support medium in EPB tunnelling

The aim of the subproject in the second funding period was the experimental rheological and hydro-mechanical characterization of foam and particle/soil foam mixtures and the continuum-based modelling based on them as a function of the composition of the fluid mixture. In the microscale, the slump test places high demands on numerical flow simulation. In principle, the explicit (weakly compressible) Smoothed Particle Hydrodynamics (SPH) formulation used allows a simulation of major problems and can also be used for further rheological investigations, e. g. of outflow from a container or silo. To analyze the effects of residual water content laboratory tests were carry out in the macroscale. Based on the results of the foam penetration tests, it is now possible to determine water contents for the conception of soil conditioning for certain situations during tunnelling with EPB shield machines. Furthermore the yield strength and the shear stresses by the shear rate of various soil-foam-mixtures were determined by rheological experiments with the Ball Measuring System.

Contact persons:
Sascha Freimann, M.Sc.
Marius Schröer, M.Sc.

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Subproject A6: Locally Transient face Support within Hydro-shields

In the 1st project phase, the time intervals of cyclic soil excavation and of slurry penetration pro-cesses at the slurry supported tunnel face were identified. The derived time scales and cutting depths of the tools served as input parameters for experimental investigations. In column tests, the effect of the complete/partly soil excavation and several stationary effects during penetration process in saturated soil were investigated. The results show the actual transferable support pres-sure at a local point of the tunnel face. For determination of the global face stability, the experi-mental results were transferred in initial numerical simulations.


Contact persons:
Dr.-Ing. Britta Schößer

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Subproject C3: Simulation of Production and Logistic Processes in Mechanized Tunneling: Simulation-Based Maintenance and Availability Analysis

The availability of tunnel boring machines and the overall productivity of mechanized tunneling projects mainly depends on the design and performance of the support and maintenance processes. The aim of this subproject is the operational analysis and management of the advancement processes including all support processes and the scheduling of maintenance work by using process simulation. A simulation model has been developed, which is easily adaptable to different project layouts and boundary condition. Uncertain input parameter are considered using distribution functions fitted on data from finished tunneling projects to enable Monte Carlo Simulations. This model has been used for the identification of bottlenecks in the supply chain and to evaluate the influence of disturbances on the productivity. Furthermore, an empirical wear prediction model for cutting tools in soft ground was adapted and utilized to analyze and improve maintenance strategies.

Contact persons:
Annika Jodehl, M.Sc.
Alena Conrads, M.Sc.

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Subproject D1: Assessment of interaction models in mechanized tunneling

The aim of this subproject is to develop concepts for generating and evaluating different layouts of the tunnel lining based on the variety of evaluation criteria. The selection of the best possible line will be implemented digitally and supported visually. A possible solution space is shown in a virtual environment. After the definition of a line, an evaluation is initiated and the evaluation results are returned and visualized in real time. In the end, it shall be possible to compare different lines with their different evaluation results.




Contact persons:
Annika Jodehl, M.Sc.
Alena Conrads, M.Sc.

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