We are pleased to present to you the GeoResources Journal issue 1-2015.
A historic retaining dam on problematic subsoil was reactivated in south Germany for protection against flooding. The reactivation concept with soil consolidation and geogrid reinforcement as well as the construction procedure are explained. Settlements established through control measurements after completion are compared with those that were originally forecast.
Financial resources for safety measures must be established with a defined residual risk. A possible approach for solving this task is described taking the example of the Gotthard Base Tunnel, the world’s longest rail tunnel.
Michael Eckl and Norbert Vogt
Spiling support consisting of umbrellas made of long pipes or self-drilling hollow-stem injection anchors find increasing application in conventional tunnel drives. Their purpose is to support the excavation face temporarily until the shotcrete is load-bearing. Despite of the frequent application, there are no codes, regulations or recommendations for the design of such support measures. This paper gives a brief summary of some results of a doctoral thesis. Finite Element Method calculations were performed to investigate the load-bearing behaviour of pipe umbrellas and to quantify the state of stresses. The principles of the bearing behaviour are shown and a simple model is presented to predict the inner forces relevant for design.
Mining and Tunnelling
Stress Measurements with the FBG Extensometer –
new Principle for Rock or Tunnel dynamic Dimensioning of underground Cavities?
Ingolf Baumann, Bernd Müller, Benjamin Litschko und Uwe Pippig
Measuring and dimensioning of underground cavities is undertaken almost exclusively by rock or tunnel mechanical methods. By applying an optical fibre BRAGG grating sensor for measuring expansion and compression states during drilling and blasting unexpectedly high stresses – caused by drill+blast – were registered, which led to supports being overloaded in underground mine workings and when driving tunnels with 2 bores. The dynamic effects are to be monitored better in future and the dimensioning of cavities adapted to rock or tunnel dynamic conditions.
The principles, prerequisites and applications for the sinking of two freeze shafts for the Ust Yayva project in Russia are described and the work accomplished hitherto including the associated planning reviewed. The approaches selected to accomplish the task and the activities already undertaken are explained. Through parallel operations – for instance installing the hoisting equipment at the sinking phase – the project was speeded up significantly. Subsequently parts of the contract that have still to be tackled are examined.
With its numerous resources, large unmapped areas of land waiting to be explored, as well as a classic and stable mining sector, Canada has long been a point of attraction for international companies. In this context, Ontario is Canada’s model province and one of the five most important regions for raw material exploration worldwide.
The next Issue will be in the German language and is coming soon...