Numerical modeling of an instrumented shallow gallery excavated in Toulouse's molasses by a conventional method

cited By 0; Conference of 8th European Conference on Numerical Methods in Geotechnical Engineering, NUMGE 2014 ; Conference Date: 18 June 2014 Through 20 June 2014; Conference Code:105581International audienceThe excavation of a shallow tunnel induces deformations of the soil volume in the vicinity and above the tunnel and consequently on the nearby buildings. The range of these deformations depends among other on the geological conditions, the geometry of the tunnel, and the excavation method. In this context, this research focuses on the 3D numerical modeling with a finite difference code of a shallow tunnel instrumented during its construction, located on the Toulouse (France) subway line B for which the excavation has been carried out in a conventional manner in an overconsolidated molassic geological context. The results of this 3D model are confronted with the in-situ measurements in order to validate the geotechnical characteristics of the molasses and consequently have useful basis for the back-analysis of the different monitoring sections implemented in areas where the tunnel excavation is made by TBM with pressurized front. © 2014 Taylor & Francis Group, London

Numerical modeling of an instrumented shallow gallery excavated in Toulouse's molasses by a conventional method

cited By 0; Conference of 8th European Conference on Numerical Methods in Geotechnical Engineering, NUMGE 2014 ; Conference Date: 18 June 2014 Through 20 June 2014; Conference Code:105581International audienceThe excavation of a shallow tunnel induces deformations of the soil volume in the vicinity and above the tunnel and consequently on the nearby buildings. The range of these deformations depends among other on the geological conditions, the geometry of the tunnel, and the excavation method. In this context, this research focuses on the 3D numerical modeling with a finite difference code of a shallow tunnel instrumented during its construction, located on the Toulouse (France) subway line B for which the excavation has been carried out in a conventional manner in an overconsolidated molassic geological context. The results of this 3D model are confronted with the in-situ measurements in order to validate the geotechnical characteristics of the molasses and consequently have useful basis for the back-analysis of the different monitoring sections implemented in areas where the tunnel excavation is made by TBM with pressurized front. © 2014 Taylor & Francis Group, London

Application of the hybrid ACP/ANFIS method for the prediction of surface settlement induced by an earth pressure tunnel boring machine with consideration of the encountered geology

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3D modeling of tunnel excavation using pressurized tunnel boring machine in overconsolidated soils

The construction of shallow tunnels in urban areas requires a prior assessment of their effects on the existing structures. In the case of shield tunnel boring machines (TBM), the various construction stages carried out constitute a highly three-dimensional problem of soil/structure interaction nd are not easy to represent in a complete numerical simulation. Consequently, the tunnelling-induced soil movements are quite difficult to evaluate. A 3D simulation procedure, using a finite ifferences code, namely FLAC3D, taking into account, in an explicit manner, the main sources of ovements in the soil mass is proposed in this paper. It is illustrated by the particular case of Toulouse ubway Line B for which experimental data are available and where the soil is saturated and ighly overconsolidated. A comparison made between the numerical simulation results and the insitu easurements shows that the 3D procedure of simulation proposed is relevant, in particular regarding he adopted representation of the different operations performed by the tunnel boring machine excavation, confining pressure, shield advancement, installation of the tunnel lining, grouting f the annular void, etc). Furthermore, a parametric study enabled a better understanding of the singular ehaviour origin observed on the ground surface and within the solid soil mass, till now not entioned in the literature

3D numerical modelling of the impact of tunnelling in soft soil on buried pipelines

cited By 0; Conference of 8th International Symposium on Geotechnical Aspects of Underground Construction in Soft Ground, TC204 ISSMGE - IS-SEOUL 2014 ; Conference Date: 25 August 2014 Through 27 August 2014; Conference Code:107325International audienceThe underground space in urban areas is congested with structures, including pipelines, which are affected by underground construction such as tunneling. This paper investigates the problem of tunneling effects on buried pipelines, using finite difference code FLAC3D. A 3D numerical pipe-soil model is developed and tunneling effect is simulated with settlement troughs which are applied at the bottom of model. 2D and 3D settlement troughs are adopted respectively to study the pipeline behavior at the final state of tunneling and in the process of tunneling. A series of numerical parametric studies is performed to analyze various combinations of settlement profiles, joint stiffness, pipe material properties and soil properties. The results are summarized and presented in a normalized plot of relative joint-pipe stiffness, relative pipe-soil stiffness, joints spacing and relative position between joints and tunnel, which are validated with an analytical approach given by Klar et al. Effect of tunneling orientation relative to pipeline is also explored. The results indicate it might be un-conservative if the analysis only considers the final state of tunneling as the critical state but neglects the variation of stress in the process of tunneling. © 2014 Korean Geotechnical Society

Numerical modeling of an instrumented shallow gallery excavated in Toulouse’s molasses by a conventional method

International audienc

Retro-analyse numérique du comportement d’un massif de sol renforcé par inclusions rigides sous chargement cyclique

International audienc