Search results for "Geotechnical Engineering"
showing 10 items of 489 documents
Volume change behaviour of a compacted scaly clay during cyclic suction changes
2010
The research presented in this paper focuses on the investigation and modelling of the volume change response of compacted tectonised clay samples subjected to several wetting and drying cycles in controlled-suction oedometers. Oedometer tests were carried out under different values of constant vertical net stress, and wetting and drying cycles were performed varying applied matric suction between 10 and 800 kPa. The investigation was complemented with a study of the material microstructure to support the interpretation of the overall mechanical response. At a microscopic level, the material is characterized by different types of particle assemblages, scales, and clay aggregates. One of th…
Experimental analysis of the water retention behaviour of shales
2014
Shales are among the most commonly considered geomaterials in current energy-related geomechanical investigations, as they are involved in engineering applications such as the unconventional extraction of natural gas, CO2 sequestration and nuclear waste geological storage. A deep understanding of their behaviour with regard to variations in the degree of saturation is of primary significance for such applications. With the aim to establish a sound protocol for shale retention behaviour analysis, this paper presents an advanced experimental methodology that takes into account the specificities of shales such as small pore size dimensions and the large variations in water potential to be appl…
Shot-clay MX-80 bentonite: An assessment of the hydro-mechanical behaviour
2014
This study presents the results of an experimental study conducted to characterise the hydro-mechanical behaviour of shot-clay MX-80 bentonite. In the shot-clay process, granular bentonite was mixed continuously with water and shot on the walls of a tunnel section at the Grimsel Underground Research Laboratory (URL), in Switzerland. The shot-clay was placed to create a layer of bentonite in direct contact with the host rock to avoid preferential water and/or gas flow along the tunnel wall. Samples for an experimental programme were collected during the shooting. The index properties, microstructural features, swelling potential and water retention properties of the shot-clay were analysed. …
Anisotropic Volumetric Response of Shales upon Suction Changes
2016
Anisotropic fabric and volumetric response to suction changes represent two main features of shales, which are involved in several engineering applications. However, a comprehensive understanding of the interaction between these two aspects is still missing. The present work aims to provide a detailed analysis of the coupling between the water retention capacity of shales and their anisotropic behaviour through an advanced experimental methodology. Among the various tested facies of the Opalinus Clay Shale (Mont Terri, Switzerland), the results from the shaly facies are presented in this study. The behaviour of the material is characterized by swelling and shrinkage respectively upon wettin…
Anisotropic volumetric behaviour of Opalinus clay shale upon suction variation
2016
Opalinus clay shale is under consideration to serve as the host geomaterial for the underground storage of nuclear waste in Switzerland. Water retention behaviour and anisotropic behaviour represent two main features of this geomaterial; however, a comprehensive understanding of the interaction between these two features is still lacking. This paper aims to provide a detailed experimental analysis of the coupling between the water retention capacity and the anisotropic behaviour of two facies (shaly and sandy) of the Opalinus clay shale. The response of the tested geomaterials is characterised by an unequal swelling and shrinkage response in directions parallel and perpendicular to the bed…
The Role of Anisotropy on the Volumetric Behaviour of Opalinus Clay upon Suction Change
2017
An experimental investigation to analyse the anisotropic volumetric response of shaly and sandy facies of Opalinus Clay upon suction variations is presented. Obtained results demonstrate the different behaviour of the tested facies to a wetting-drying cycle. The shaly facies exhibits higher water retention capacity and stronger volumetric response than the sandy facies. Anisotropic response is experienced by both facies with the strain perpendicular to bedding higher than in the parallel direction. The sandy facies exhibits a more pronounced anisotropic behaviour in particular during the drying phase. A detailed analysis of the response in the two directions with respect to the bedding orie…
In-lab versus on-site measurement of surface performance of flexible pavements
2017
Road safety is one of the major problems which affect our society. Skid resistance mainly depends on a pavement surface microtexture and macrotexture. Macrotexture can be easily measured on site through the Sand Patch method (mean texture depth, MTD, UNI EN 13036-1, ASTM E 965, CNR B.U. 94/83). Carrying out the measurements above on the samples, in the laboratory, at the preliminary stage of the design of the pavement, would enhance the design in terms of timing and costs. In the light of the above, the objective of the study presented in this paper is to set up and validate a method for deriving the sand patch value based on core measurements. A Predictive relationship is proposed in terms…
Thermal inertia modeling for soil surface water content estimation: A laboratory experiment
2012
We are proposing a new method for estimating soil surface water content from thermal inertia distributions retrieved from visible–near infrared (VISNIR)and thermal infrared (TIR) images. A drying experiment was conducted on three fi ne-textured soils while acquiring multispectral VIS-NIR and TIR images. Simultaneous measurements of soil water content and thermal inertia were conducted by the thermogravimetric method and the heat pulse technique, respectively. Direct measurements were used to test the thermal inertia approach proposed by Murray and Verhoef that requires only knowledge of soil porosity and can be easily inverted to derive soil water content from thermal inertia. For the three…
Citizens’ perceptions in relation to transport systems and infrastructures: a nationwide study in the dominican republic
2021
One of the challenges currently faced by emerging countries is to get their citizens to decide to use sustainable transport for their regular trips, in order to reduce the current vehicular pollution rates. The objective of this descriptive research is to examine the perceptions of Dominicans regarding the state of the country’s transport systems and road infrastructure. For this purpose, a nationwide survey procedure was performed. This cross-sectional research used the data retrieved from a sample of 1260 citizens aged over 18, proportional in gender, age, habitat, and province of the Dominican Republic. The results showed how Dominicans believe that, compared to other road features, pede…
Land Surface Temperature Retrieval Methods From Landsat-8 Thermal Infrared Sensor Data
2014
The importance of land surface temperature (LST) retrieved from high to medium spatial resolution remote sensing data for many environmental studies, particularly the applications related to water resources management over agricultural sites, was a key factor for the final decision of including a thermal infrared (TIR) instrument on board the Landsat Data Continuity Mission or Landsat-8. This new TIR sensor (TIRS) includes two TIR bands in the atmospheric window between 10 and 12 $\mu\hbox{m}$ , thus allowing the application of split-window (SW) algorithms in addition to single-channel (SC) algorithms or direct inversions of the radiative transfer equation used in previous sensors on board …