References of "Engineering Geology"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailNumerical modeling of coupled thermal-hydro-mechanical behavior of GMZ bentonite in the China-Mock-up test
Zhao, Jingbo; Chen, Liang; Collin, Frédéric ULg et al

in Engineering Geology (2016), 214

Gaomiaozi (GMZ) bentonite is currently considered as themost suitable buffermaterial for high-level radioactive waste geological repository in China. To investigate the long-term performance of GMZ ... [more ▼]

Gaomiaozi (GMZ) bentonite is currently considered as themost suitable buffermaterial for high-level radioactive waste geological repository in China. To investigate the long-term performance of GMZ bentonite under repository conditions, a large scale mock-up test has been carried out since 2011. In the test, a hydration systemand an electrical heater were employed to simulate the Thermal-Hydro-Mechanical (THM) coupled conditions near a repository. In this work, a numerical study is performed to reproduce the experimental data obtained in the first three years of the China-Mock-up experiment. The principle THM characteristics and parameters of the bentonite are presented. On this basis, a THM coupled constitutive model is introduced. With the proposed model, numerical simulations of the China-Mock-up test are carried out using LAGAMINE. The numerical data of temperature, relative humidity, and swelling pressure of the GMZ compacted bentonite are compared with the experimental ones.We discuss the effect of the balance between the drying effect and water penetration process on the THM behavior of the GMZ bentonite. The good agreement between the predicted and experimental results suggests that the proposed model can reproduce the fundamental behavior of GMZ compacted bentonite under coupled THM conditions. [less ▲]

Detailed reference viewed: 14 (2 ULg)
Full Text
Peer Reviewed
See detailHydrogeological assessment of non-linear underground enclosures
Pujades, Estanislao ULg; Jurado Elices, Anna ULg; Carrera, Jesus et al

in Engineering Geology (2016), 207

Excavations below the water table are usually undertaken by combining the protection of retaining walls with dewatering by pumping wells. Severe difficulties may arise if the retaining walls have defects ... [more ▼]

Excavations below the water table are usually undertaken by combining the protection of retaining walls with dewatering by pumping wells. Severe difficulties may arise if the retaining walls have defects. Therefore, their state must be determined and, if needed, the defects repaired or the dewatering system redesigned. The state of underground retaining walls can be evaluated using hydrogeological methods, but these methods are well-established only for linear excavations. The objective of this work is to propose a procedure to evaluate the state of non-linear underground enclosures by analyzing the groundwater response to pumping inside the enclosure. The proposed method, which is based on diagnostic plots (derivative of drawdown with respect to the logarithm of time), allows (1) determining if an underground non-linear enclosure has isolated openings or numerous defects and (2) computing its effective conductance or effective hydraulic conductivity. The methodology is tested with data collected during the excavation of a shaft required for the construction of the high speed train (HST) tunnel in Barcelona, Spain. The procedure can be applied using the wells drilled for dewatering. Although a test before the excavation is recommended to evaluate the underground retaining walls (Watertightness Assessment Test), the method can be applied using data collected at the beginning of the dewatering stage. [less ▲]

Detailed reference viewed: 39 (13 ULg)
Peer Reviewed
See detailHydromechanical modelling of shaft sealing for CO2 storage
Dieudonné, Anne-Catherine ULg; Cerfontaine, Benjamin ULg; Collin, Frédéric ULg et al

in Engineering Geology (2015), 193

The geological sequestration of CO2 in abandoned coal mines is a promising option to mitigate climate changes while providing sustainable use of the underground cavities. In order to certify the ... [more ▼]

The geological sequestration of CO2 in abandoned coal mines is a promising option to mitigate climate changes while providing sustainable use of the underground cavities. In order to certify the efficiency of the storage, it is essential to understand the behaviour of the shaft sealing system. The paper presents a numerical analysis of CO2 transfer mechanisms through a mine shaft and its sealing system. Different mechanisms for CO2 leakage are considered, namely multiphase flow through the different materials and flow along the interfaces between the lining and the host rock. The study focuses on the abandoned coal mine of Anderlues, Belgium, which was used for seasonal storage of natural gas. A two-dimensional hydromechanical modelling of the storage site is performed and CO2 injection into the coal mine is simulated. Model predictions for a period of 500 years are presented and discussed with attention. The role and influence of the interface between the host rock and the concrete lining are examined. In addition the impact of some uncertain model parameters on the overall performance of the sealing system is analysed through a sensitivity analysis. [less ▲]

Detailed reference viewed: 85 (14 ULg)
Full Text
Peer Reviewed
See detailAn unsaturated hydro-mechanical modelling of two in-situ experiments in Callovo-Oxfordian argillite
Charlier, Robert ULg; Collin, Frédéric ULg; Pardoen, Benoît ULg et al

in Engineering Geology (2013), 165

The unsaturated behaviour of Callovo-Oxfordian argillite is investigated through the modelling of 2 in-situ experiments. The first test studies the influence of ventilation in a gallery on the hydro ... [more ▼]

The unsaturated behaviour of Callovo-Oxfordian argillite is investigated through the modelling of 2 in-situ experiments. The first test studies the influence of ventilation in a gallery on the hydro-mechanical behaviour of the rock mass. The second test consists in a gas injection in the rock mass from an experimental borehole. A hydro-mechanical model is described and used in the modelling of the experiments. A review of the main hydro-mechanical parameters of argillite is presented. The numerical results highlight the need of a flow boundary condition reproducing the fluid transfers between the surroundings and the rock mass. The influence of dissolved gas on the compressibility of the liquid phase is also emphasised. [less ▲]

Detailed reference viewed: 81 (34 ULg)
Full Text
Peer Reviewed
See detailTracking landslide displacements by multi-temporal DTMs: A combined aerial stereophotogrammetric and LIDAR approach in western Belgium
Dewitte, Olivier ULg; Jasselette, J. C.; Cornet, Yves ULg et al

in Engineering Geology (2008), 99(1-2), 11-22

Detailed reference viewed: 79 (24 ULg)
Full Text
Peer Reviewed
See detailSite effects modelling applied to the slope affected by the Suusamyr earthquake (Kyrgyzstan, 1992)
Bourdeau, Céline ULg; Havenith, Hans-Balder ULg

in Engineering Geology (2008), 97

In 1992, a large magnitude earthquake (Ms=7.3) hit the northern part of the Kyrgyz Tien Shan range where it triggered rockslides and many debris slides or flows. One of these mass movements occurred on ... [more ▼]

In 1992, a large magnitude earthquake (Ms=7.3) hit the northern part of the Kyrgyz Tien Shan range where it triggered rockslides and many debris slides or flows. One of these mass movements occurred on the Chet–Korumdy ridge located in the Suusamyr Basin. It consists of a multi-rotational debris slump in its upper part that turned into a debris flow in its lower part. Involving arenitic material overlying silty clays, it has a volume of about 0.5 to 1.106 m3, a maximum thickness of 40mand a run-out of 200 m. The field observations and measurements carried out on this slope suggest that local amplification effects could have contributed to the initiation of the seismic failure. To test this hypothesis in the lack of instrumental evidence of local ground-motion recordings, we conducted a sensitivity study of site effects based on a numerical analysis in the visco-elastic domain with a twodimensional finite difference code. Varying the topography and the geology of the investigated slope, topographic site effects are found to be less important than geological site effects which are controlled by the contrast of impedance between the surface materials and the bedrock. The geometry of the low-velocity surface layer has also an influence on site effects, which is often difficult to be distinguished from pure topographic effects. Considering all modelling results, we conclude that site amplifications alone cannot have triggered the Suusamyr landslide during the 1992 earthquake. The static slope stability analyses done in previous studies revealed that the Suusamyr failure neither can have a purely static origin. Even if the water table is very high within the arenite layer, only a minor failure develops in the lower part of the slope. Therefore, we believe that the triggering of the Suusamyr landslide is a consequence of pore pressure build up in areas characterized by significant ground-motion amplifications. [less ▲]

Detailed reference viewed: 44 (3 ULg)
Full Text
Peer Reviewed
See detailInfluence of morphological characteristics of heterogeneous moraine formations on their mechanical behaviour using image and statistical analysis
Lebourg, Thomas; Riss, Joelle; Pirard, Eric ULg

in Engineering Geology (2004), 73(1-2), 37-50

The study of landslide stability on mountain slopes becomes more difficult when the sliding materials. are heterogeneous. This is a current problem with the old glacial moraines now under study in the ... [more ▼]

The study of landslide stability on mountain slopes becomes more difficult when the sliding materials. are heterogeneous. This is a current problem with the old glacial moraines now under study in the Aspe Valley, Pyrenees. Analysis of slope stability numerical models necessitates accurate data about mechanical and physical properties. Because moraines are very heterogeneous, a large sample is necessary, but, unfortunately, data acquisition costs a lot of time and money. Therefore, we would like to estimate mechanical properties from correlated variables that are easier to acquire (morphological variables using image analysis). Observations in the field and previous mechanical results in the laboratory have shown that differences between the behaviour of moraines seem to be related not only to their three-dimensional structure but also to the morphological and petrographical characteristics of their components. The moraines are classified based on textural characteristics at the sample scales based on the distributions of size and shape of their constitutive elements (blocks, matrix, etc.). Then, we study the statistical distribution of the variables to highlight the most significant variables. Next, we evaluate the results of the mechanical behaviour of the moraines, with the internal angle of friction and the effective cohesion. On seven specific moraines, we established relations between the effective internal angle of friction, the elongation factor and the roughness factor. (C) 2003 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 58 (2 ULg)
Full Text
Peer Reviewed
See detailThermo-hydro-mechanical coupling in clay barriers
Collin, Frédéric ULg; Li, Xian-Ling; Radu, Jean-Pol ULg et al

in Engineering Geology (2002), 64(2-mars Sp. Iss. SI),

A thermo-hydro-mechanical model is presented to tackle the complex coupling problems encountered in clay barriers. A detailed formulation. coupling heat, moisture (liquid water and water vapour) and air ... [more ▼]

A thermo-hydro-mechanical model is presented to tackle the complex coupling problems encountered in clay barriers. A detailed formulation. coupling heat, moisture (liquid water and water vapour) and air transfer in a deformable unsaturated soil is given. The formulation of Alonso-Gens' mechanical model for unsaturated soil is also incorporated. Finally, a small-scale wetting-heating test on compacted bentonite is performed for validation; the numerical results are compared to the experimental measurements. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲]

Detailed reference viewed: 96 (25 ULg)
Full Text
Peer Reviewed
See detailGeotechnical properties of the Quaternary sediments in Shanghai
Dassargues, Alain ULg; Biver, Pierre; Monjoie, Albéric ULg

in Engineering Geology (1991), 31(1), 71-90

The subsoil of Shanghai is composed of Quaternary sediments of the Yangtse River estuary. The center of the city has undergone a man-induced subsidence due to water pumping in the confined multi-aquifer ... [more ▼]

The subsoil of Shanghai is composed of Quaternary sediments of the Yangtse River estuary. The center of the city has undergone a man-induced subsidence due to water pumping in the confined multi-aquifer system located in these sediments. Together with a sedimentological study of the post-Pleistocene conditions of deposition and accumulation, an accurate geotechnical study has been completed on the basis of all the available data from identification, oedometer and triaxial tests. Size analysis, X-ray analysis, compressibility characteristics, void ratio, preconsolidation pressures, permeabilities are considered taking into account the sedimentary sequence. Some relations between parameters are deduced and the hydrodynamic parameters are related to compaction parameters in order to predict their coupled and non-linear effects on the subsidence phenomena. Conclusions consist in the determination of the zones where different sensitivities to compaction are evaluated in these Quaternary formations. [less ▲]

Detailed reference viewed: 41 (7 ULg)