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List of products by author: M. Thewes
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Potential of the newly developed High Density Support Medium (HDSM) for the application of Variable Density (VD)-TBM...
Abstract: On their first application for the Klang Valley MRT-Project in Kuala Lumpur, the Variable Density (VD)-TBMs had to bore through very karstic limestone in mixed face conditions with hard rock and soft ground. This type of TBM technology was also applied for other tunnelling projects with highly heterogeneous, very coarse and permeable ground in some instances under a high ground water level....
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Practical Application of a Cement-free Shotcrete for Tunnel Refurbishment
Abstract: Existing road and railway tunnels in Central Europe increasingly show signs of aging and deterioration, which is particularly evident in the tunnels’ inner lining. Due to dramatic tunnel fires, and novel research findings, German authorities have reviewed and revised several guidelines for the design of tunnel structures in recent years. In the national research project KOINOR, a cement-free...
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Practical Relevance of Rheology of Foam-conditioned Sands in EPB Tunneling
Abstract: At the previous WTC 2016, the rheological characterization of soil-foam mixtures was presented by means of the slump test. Measurements from numerous slump tests were considered in analytical models enabling a derivation of rheological parameters. In this publication, the rheological analysis of soil-foam mixtures is extended to rheometer testing. By conducting experiments on different scales,...
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Prediction of the dispersion of soil in slurry shield tunneling
Abstract: Shield machines with a slurry supported face are typically used in non-cohesive soils. Still, these machines quite often also encounter cohesive soils or soils with a high content of fines. In fine-grained soil it cannot be avoided that a certain amount of the fine particles disperses into the slurry. On the one hand this effect is welcome because to a certain extent it enhances the rheological...
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Proposed Methodology for Clogging Evaluation in EPB Machines
Abstract: Clogging occurrence has long been an issue for EPB drives, through not only pure clay soils, but also in mixed soils with sufficient clay content for clogging to happen. It occurs when clay particles adhere to metal surfaces of excavation tools because of the attractive forces of the clay particles and the presence of water between the clay-metal surface. The occurrence of clogging in Earth...
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Recommendations for Efficient Face Support in Slurry Shield Tunnelling
Abstract: In slurry shield tunnelling, a reliable face support is presumed if a support pressure is transferred and the slurry excess pressure provides efficient support pressure on the soil skeleton. To ensure face stability, the support pressure transfer needs to be provided within the theoretical sliding wedge after Horn (1961) at the tunnel face. Therefore, the penetration depth of the bentonite...
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Separation of used bentonite suspensions in slurry shield tunneling: improvement of depositing costs by introduction...
Abstract: High costs and ecological impacts of separation and disposal of used bentonite suspen-sions are driving forces of the operating efficiency of slurry shield tunneling. This paper introduces a new method for improvement of the conventional separation processes by means of electrocoagulation. This method is based on the physical principles of electrolysis and consists of applying electrical...
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Simulation-based TBM performance prediction
Abstract: Fast growing urban areas put high requirements on the existing infrastructure systems. Due to limited surface space in this high populated areas the demand for underground projects increased continiousily in the last few decades. Frequently, finished projects do not reach the highest possi-ble production performance. Reasons for this are complex and can often not be identified clearly. The...
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Soil Conditioning with Artificial Soil and Foam in EPB-Tunneling
Abstract: In mechanised tunnelling with EPB-shields operating in closed mode, the excavated soil is used as support medium in order to assure a sufficient stabilisation of the tunnel face. Coarse grained or high permeable soils doesn’t exhibit adequate conditions to be used as a support medium in an EPB shield, which require the increase of cohesion and plastic behaviour of the excavated soil. In this...
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