Laboratory of Mine Design

Mining and Geomechanical Applications

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Some new developments on the representation and standardization of rock mechanics data: From the laboratory to the full scale project

G. Exadaktylos, P. Liolios & G. Barakos

Department of Mineral Resources Engineering, Technical University of Crete, Chania, Greece


An effort has been made to create a Rock Mechanics Database that may be used in the future as a tool for the design of excavations in rocks. This is the reason it was designed to be web-driven through the UCIS platform of TUNCONSTRUCT (Technology Innovation in Underground Construction, Its main feature is that it is hierarchical, that is, it starts from the mineralogical-microstructural characterization and reduced raw lab mechanical testing data, then it goes to the data referring to the behavior of the rock in loading and unloading-reloading, as well as to post-peak behavior, separately, after it goes to the identification of elasticity moduli, then to plasticity and damage properties of the rock according to an appropriate constitutive mechanical model, and so on. In order to achieve this for different tests on the same rock - that may be performed by different laboratories - some kind of standardization of procedures is required although not significant departure from established ISRM Standardization Procedures of basic rock mechanics tests is being made. These procedures are discussed here. The next thing to consider is how to upscale the parameters of the intact rock identified from lab testing to the real life scale of the project.

Invited paper in the, 11th ISRM Congress: Rock Mechanics Data: Representation and Standardisation, D. Toll Chairman, July 12th 2007, Lisbon Congress Centre, Lisbon Portugal.


Geotechnical EPB model for Mas-Blau L9 section (Barcelona), EUROTUN:2009:933-954

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A geotechnical and EPB model of Mas-Blau L9 metro tunnel in Barcelona

Maria Stavropoulou1, George Exadaktylos2, George Xiroudakis2 and George Saratsis2

1Dept. of Dynamic Tectonic and Applied Geology, Faculty of Geology and Geo-Environment, University of Athens, Greece

2Dept. of Mineral Resources Eng., Technical University of Crete, Chania, Greece


A challenging topic in soft ground tunnelling engineering is how the predominant geotechnical parameters of the soils are modeled inside the 3D domain of interest, since this model feeds the numerical model for subsequent excavation performance, stability, subsidence and risk calculations. Care must also be given to the appropriate modeling of the geometry of the distinct geological layers that could create problems during underground construction. One way to do this is by following a similar procedure with that proposed here for the geotechnical parameters, i.e. through the use of a geostatistical interpolation technique such as kriging or simulation annealing; the latter bypasses the smoothing effect induced by the former method. Another interesting aspect of tunnelling is how to take into account TBM logged data as boring of the tunnel progresses, for the continuous improvement (feedback) of the geotechnical model. This paper presents first the geostatistical methodology for the transformation the conceptual geological model into a geotechnical model and second a first EPB performance model that enhances the prior geotechnical model and constitutes a first “underground construction environment model” for the Mas-Blau section of Metro L9 in Barcelona.

Keywords: Mechanized tunnelling, Geological model, Geostatistics, EPB, cutting knives, Risk