Papers by Richard Kastner
Current design standards do not take account of soil variability along buried sewer pipes ignorin... more Current design standards do not take account of soil variability along buried sewer pipes ignoring the longitudinal bending. However, considering the current installation practice it appears obvious that the bedding or loading conditions are not uniform. In order to quantify the amount of disorders that originate from the longitudinal pipe behavior a statistical analysis of CCTV inspections outcome gathered in the Greater Lyon, France is used. It appears indeed that the major part of the observed defects might be related to the longitudinal behavior. An explanation of this result may be given both by a statistical and numerical approach. A statistical model developed from the database helps to identify some factors that may contribute to the failure occurrence within buried pipes by longitudinal bending. The performed numerical 3D simulations analyze the effect of both the pipe joint and the most common bedding heterogeneities.
HAL (Le Centre pour la Communication Scientifique Directe), Nov 1, 2010
International audienc
Taylor & Francis eBooks, Apr 11, 2005
The calculations of flexible retaining walls based on the Winkler assumption can be criticized in... more The calculations of flexible retaining walls based on the Winkler assumption can be criticized in theory, but are increasingly used. This paper compares these calculations with a series of model tests, highlighting the possibilities and limitations of the method. The program used is based on the assumption of the modulus of subgrade reaction and limited values of active and passive earth pressure, while taking the soil hysteresis into account. Comparisons with conventional calculations and the finite element method are also presented. For the covering abstract of the conference see IRRD 287689. (TRRL)
A part of Toulouse's underground line B has been excavated by a 7.8 meters diameter earth-pressur... more A part of Toulouse's underground line B has been excavated by a 7.8 meters diameter earth-pressure balance machine. A comprehensive monitoring section has been installed in the Compans garden at a point where the tunnel cover is 12.8-meter and is running through overconsolidated clayey molasses underlying a 6.8 meters layer of made ground and gravels. The monitoring devices give full information on the ground movements above the tunnel and on deformations of the tunnel lining. Vertical movements are measured by 5 multipoint borehole extensometers with automatic data acquisition (every 5 seconds when the TBM crosses the monitoring section). At the end of each excavation phase, a high precision levelling of the borehole extensometer heads is performed in order to determine the total vertical displacements. Horizontal movements are measured by 3 inclinometers, one in the axis of the tunnel and the others on its sides, 2.3 meters away from the tunnel extrados. One of these inclinometers is 42 m long, i.e. 21.8 m below the level of the tunnel invert. The induced horizontal strains at ground level are measured by an invar thread in both longitudinal and transverse directions. Measurements show a specific behaviour of the soil due to its overconsolidated character (K 0 greater than 1.5): even though the magnitude of the displacements is limited to a few millimeters, horizontal convergent movements are observed at the level of the tunnel axis while 3 to 4 times smaller heave is measured at ground surface (associated with horizontal extensions). Excavation parameters are automatically recorded and give information on the variation of the torque on the cutting wheel, the advancement rate, the confining pressure, the injection of annular void between soil and the concrete tunnel lining… This paper presents the results of the different monitoring devices and the possible correlations with the tunnel excavation parameters recorded by the TBM.
Taylor & Francis eBooks, Apr 11, 2005
Taylor & Francis eBooks, Jul 12, 2006
CRC Press eBooks, May 10, 2021
Tunnels et ouvrages souterrains, 2008
As the slurry shield tunnels of great dimension are widely used in recent years around the world ... more As the slurry shield tunnels of great dimension are widely used in recent years around the world , particular attention is paid to face stability of large or extra-large slurry shield driven-tunnels (Chapter 1). This thesis proposes to deal with the problem using three types of approaches, especially with the back ground of Shanghai Yangtze Tunnel. Firstly, experiments using a small scale laboratory mode to simulate the construction of a slurry shield driven-tunnel performed (Chapter 2). Then, upper-bound approach in limit analysis (Chapter 3) and three-dimensional numerical modeling (Chapter 4) are presented. Both the local failure and global failure in collapse and blow-out are studied when taking into account the characteristics of shield tunnels with large diameter. Finally, the parametric sensibility analysis of large slurry shield tunnel face stability is studied by numerical modeling (Chapter 5). A modified solution of local face stability taking into consideration different construction methods (represented mainly by the unit weight of support medium) is proposed and the partial failure mechanism especially for large slurry shield tunnels is firstly presented in this thesis. The failure mechanisms and critical slurry obtained from both the upper bound approaches and numerical simulations are compared with each other.
Proceedings of the 6th International Symposium (IS-Shanghai 2008), 2008
Geotechnical Aspects of Underground Construction in Soft Ground, 2012
Proceedings of the 5th International Workshop, Guimaraes, Portugal 1–4 April 2007, 2007
Proceedings of the 5th International Symposium TC28. Amsterdam, the Netherlands, 15-17 June 2005, 2006
Géotechnique, 2002
Soils or soft rocks reinforced with linear inclusions constitute a composite material which is di... more Soils or soft rocks reinforced with linear inclusions constitute a composite material which is difficult to numerically model, due to large contrasts between the deformation module and differences of scale. The homogenisation of recurring environments means that the behaviour of macroscopic materials such as these can be considered under certain conditions. In this article, the technique is described and the anisotropic behaviour of the homogenised material and its positioning in an axial symmetry numerical code is outlined. The comparison with a three-dimensional analysis of homogeneous loadings allows the limits of this approach to be studied. Lastly, the comparison of the homogenisation technique with three-dimensional modelling is carried out on deep tunnels reinforced at the coalface.
Canadian Geotechnical Journal, 2004
Urban soils are generally heterogeneous and thus require, for any project, careful geotechnical e... more Urban soils are generally heterogeneous and thus require, for any project, careful geotechnical evaluation. Considering the difficulty faced by geotechnical engineers in defining a model of the underground (different soil layers and associated physical-mechanical properties), it appears useful to clearly define a strategy for the analysis of the site investigation results. As well as an in-depth knowledge of the site, this strategy should rely on carefully defined general rules of analysis and treatment of collected data. The processes leading to a representative and accurate model of the volume of soil affected by the underground works are identified in this paper based on the analysis of a case study (extension of the Lyon subway line D). Variability is one of the main features of urban soils, therefore one should be able to quantify and compare this variability with other sources of uncertainties and inaccuracies affecting the design process, such as the quality of measurements a...
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Papers by Richard Kastner