Jean-Pierre Gourc
University of Grenoble
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Featured researches published by Jean-Pierre Gourc.
Waste Management | 2010
Jean-Pierre Gourc; Matthias J. Staub; M. Conte
Forecasting settlements of non-hazardous waste is essential to ensure the integrity and durability of landfill covers over time. Over a short time span, the survey of settlements may also contribute to the investigation of the biodegradation processes. This paper addresses secondary settlements of Municipal Solid Waste (MSW), a heterogeneous and time-evolving material. An analysis of available experimental data from different pilots and the literature was conducted to quantify the influence of biodegradation on MSW secondary settlements. After making assumptions about the various features of the waste and their constitutive relationships, a one-dimensional biomechanical model to predict the secondary settlement has been developed. The determination of the total secondary settlement was obtained by the addition of two separate parts, the mechanical settlement, due to creep, and the biochemical settlement, due to the degradation of the organic matter. The latter has been evaluated based on the observed biogas production. Using the data from different recent large-scale experiments that provide a monitoring of biogas production, a method for predicting the biochemically-induced settlements is proposed and validated on these tests. The relative contributions of mechanical and biochemical settlements are also calculated and discussed as a function of waste pre-treatment and operation conditions (biological pre-treatment, shredding, leachate injection). Finally, settlement may be considered as a relevant indicator for the state of biodegradation.
Journal of Contaminant Hydrology | 2010
Guillaume Stoltz; Jean-Pierre Gourc; Laurent Oxarango
A novel set of experimental apparatus was designed and constructed to study the changes in the fluid-flow properties of municipal solid waste (MSW) related to the physical evolution of its structure under compression. The vertical liquid and gas permeabilities of MSW samples were measured in a laboratory-constructed cell termed an oedopermeameter. Another original device, a gas pycnometer, was employed to assess the volumetric gas content of the porous medium. Finally, the horizontal gas permeability of the compressed MSW sample was measured using another laboratory-constructed cell called a transmissivimeter. The results made it possible to characterise the intrinsic gas permeability as a function of porosity. Additionally, gas permeability measurements of samples with different liquid contents allowed the derivation of gas permeability correlations as functions of the physical parameters of the medium. A unique relationship was found between the gas permeability and the volumetric gas content.
Waste Management | 2010
Guillaume Stoltz; Jean-Pierre Gourc; Laurent Oxarango
Following the basics of soil mechanics, the physico-mechanical behaviour of municipal solid waste (MSW) can be defined through constitutive relationships which are expressed with respect to three physical parameters: the dry density, the porosity and the gravimetric liquid content. In order to take into account the complexity of MSW (grain size distribution and heterogeneity larger than for conventional soils), a special oedometer was designed to carry out laboratory experiments. This apparatus allowed a coupled measurement of physical parameters for MSW settlement under stress. The studied material was a typical sample of fresh MSW from a French landfill. The relevant physical parameters were measured using a gas pycnometer. Moreover, the compressibility of MSW was studied with respect to the initial gravimetric liquid content. Proposed methods to assess the set of three physical parameters allow a relevant understanding of the physico-mechanical behaviour of MSW under compression, specifically, the evolution of the limit liquid content. The present method can be extended to any type of MSW.
Journal of Hazardous Materials | 2010
Matthias J. Staub; Jean-Pierre Gourc; J.-P. Laurent; C. Kintzuger; Laurent Oxarango; H. Benbelkacem; Rémy Bayard; C. Morra
This paper investigates the measurement of moisture content in municipal solid waste using two different indirect techniques: neutron scattering and time-domain reflectometry (TDR). Therefore, six laboratory-scale landfill bioreactors were instrumented with both neutron and TDR probes; in addition to that a gravimetric moisture balance was established for each cell. Different leachate recirculation modes were applied to perform different wetting conditions. In a first step, both probes were calibrated based on the water balance from three cells presenting homogeneous water distributions and sufficient temporal moisture variations. The calibration functions were then used for temporal and spatial moisture monitoring of all six cells. The results show that both methods are sensitive to moisture variations and provide interesting information on the complexity of vertical flows within the municipal solid waste. Nevertheless, it appears that neutron scattering offers better accuracy at the laboratory scale.
Waste Management | 2011
A-J. Tinet; L. Oxarango; Rémy Bayard; Hassen Benbelkacem; Guillaume Stoltz; M.J. Staub; Jean-Pierre Gourc
The optimisation of landfill operation is a key challenge for the upcoming years. A promising solution to improve municipal solid waste (MSW) management is the bioreactor technology. A meso-scale (around 1m(3)) experimental set-up was performed to study the effect of moisture control in low density conditions with different leachate injection operations and bioreactor monitoring including the use of a neutron probe. The moisture content distribution evolution demonstrates a multi-domain flow behaviour. A classic van Genuchten-Mualem description of the connected porosity proved insufficient to correctly describe the observed phenomena. A bimodal description of the connected porosity is proposed as solution and a connected/non-connected porosities numerical model was applied to the results. The model explains the experimental results reasonably well.
Journal of Hazardous, Toxic, and Radioactive Waste | 2013
Matthias J. Staub; Jean-Pierre Gourc; Nicolas Drut; Guillaume Stoltz; Alicia A. Mansour
AbstractMunicipal solid waste (MSW) in landfill bioreactors is subjected to mechanical, biological, and hydrological processes. To understand these processes, four large-scale bioreactor pilots were specifically designed to simulate the behavior of waste in the core of a landfill. Here, the results of two long-term tests that were performed in two compression cells are presented. Mechanical, biochemical, and hydrological parameters were analyzed throughout the experiments. The promising results of this research improve the understanding of biodegradation and its correlation with the hydromechanical behavior of municipal solid waste. In particular, the sensitivity of the biodegradation to leachate injection and the correlation between the biogas flow and vertical settlement were confirmed for wastes with high initial moisture content. The results showed that it is important to consider the potential of different monitoring techniques and the representative volume for the experimental approach. Furthermore,...
Geotechnical and Geological Engineering | 2000
Elisabeth Haza; Philippe Gotteland; Jean-Pierre Gourc
This paper presents a method for the design of geosynthetic reinforced soil structures, adapted for the case of a local surcharge load. The load has an important influence on the mechanical behaviour of the reinforcement. The basic calculation method is described and a design calculation method is proposed for the case of a locally loaded structure. This new approach is validated on the basis of experimental results obtained on several full-scale embankments, locally loaded to failure. These experimental results are compared to the results of calculation with partial safety factors from Eurocode 7.
Geotechnical Testing Journal | 2011
Heraldo Nunes Pitanga; Jean-Pierre Gourc; Orencio Monje Vilar
Composite lining systems comprising different geosynthetics and soil are typical capping devices in modern landfills. Analyses of the behavior of capping devices have shown that they are very sensitive components thanks in part to the shear strength of geosynthetic interfaces, many of which were reported to have controlled slippage between capping lining components during landfill slope failures. There are some laboratory testing alternatives for measuring the shear strength of the interface between geosynthetics or between geosynthetics and soil. The inclined plane test is especially appropriate for shear strength tests under low normal pressure which is a specific condition of these geosynthetic systems on cap cover. However, the selected shear strengths, inferred from the laboratory experimentation, show considerable variability, which depends on the test procedure. This work proposes a new procedure and a new interpretation of the inclined plane test taking as an example the interface between geospacers and geomembranes often considered as a critical interface. The measurement of displacement acceleration during the test gives the possibility of more accurately defining the large sliding displacement shear strength, which may approach the true residual condition.
Waste Management | 2007
Franck Olivier; Jean-Pierre Gourc
Journal of Geotechnical and Geoenvironmental Engineering | 2012
Guillaume Stoltz; Anne-Julie Tinet; Matthias J. Staub; Laurent Oxarango; Jean-Pierre Gourc