Search results for "water retention"

Modelling the Water Retention Domain of a Compacted Scaly Clay

2012

A body of experimental data on the water retention behaviour of compacted samples of an Italian scaly clay is analysed. The mechanical and the hydraulic behaviour of compacted samples of this clay are governed by multi-scale arrangement of scales and aggregates, which characterises the compacted clay fabric. At least two different pore networks, namely intra-aggregate and inter-aggregate, may be identified, which interact one with the other along coupled hydro-mechanical paths. The retention behaviour is interpreted in the framework of a comprehensive multi-scale modelling approach recently proposed for compacted clays of low and medium activity, which proves to be able to account for the i…

Advances in the Testing of the Hydro-mechanical Behaviour of Shales

2013

The paper presents some of the advanced experimental techniques and apparatuses that have been developed by the authors for testing the hydromechanical behaviour of shales. A methodology established for the analysis of the water retention behaviour in non-isochoric conditions is introduced; the method allows for the determination of the main drying and wetting paths in addition to the volume change response upon total suction variations. A high-pressure oedometric cell is then presented; the apparatus allows for the analysis of the transition from the pre-yield behaviour to the normally consolidated state. The analysis of the settlement versus time curves yields information on the permeabil…

A review of preferential water flow in soil science

2018

A better understanding of preferential water flow is important because water-related crises, i.e., water scarcity and security, are strongly associated with water retention rates in different landscapes. This review aims to evaluate significant advances in the main themes of preferential water flow to establish the inconsistent roles of preferential water flow in eco-hydrology and suggest promising areas for future work. Results showed that preferential water flow studies have made significant advances in our understanding of certain parameters functioning at multiple scales but that most studies focus on preferential water flow in the vadose zone, whereas few studies on the soil surface. …

An assessment of the BEST procedure to estimate the soil water retention curve: A comparison with the evaporation method

2018

The Beerkan Estimation of Soil Transfer parameters (BEST) procedure is an attractive, easy, robust, and inexpensive way for a complete soil hydraulic characterization but testing the ability of this procedure to estimate the water retention curve is necessary as relatively little information is available in the literature. In this investigation the soil water retention curve was predicted for four differently textured soils by applying three existing BEST algorithms (i.e., slope, intercept and steady) and the results compared with those measured by the standard Wind evaporation method. A sensitivity analysis of the infiltration constants, beta and gamma, was also carried out and their impac…

How and why does willow biochar increase a clay soil water retention capacity?

2018

Addition of biochar into a soil changes its water retention properties by modifying soil textural and structural properties. In addition, internal micrometer-scale porosity that is able to directly store readily plant available water affects soil water retention properties. This study shows how precise knowledge of the internal micrometer-scale pore size distribution of biochar can deepen the understanding of the biochar-water interactions in soils. The micrometer-scale porosity of willow biochar was quantitatively and qualitatively characterized using X-ray tomography, 3D image analysis and Helium ion microscopy. The effect of biochar application on clay soil water retention was studied by…

Investigation into water retention behaviour of deformable soils

2013

The paper presents an experimental and modelling approach for the soil-water retention behaviour of two deformable soils. The objective is to investigate the physical mechanisms that govern the soil-water retention properties and to propose a constitutive framework for the soil-water retention curve accounting for the initial state of compaction and deformability of soils. A granular soil and a clayey soil were subjected to drying over a wide range of suctions so that the residual state of saturation could be attained. Different initial densities were tested for each material. The soil-water retention curves (SWRCs) obtained are synthesized and compared in terms of water content, void rati…

Etude de la variabilité des propriétés physiques et hydrodynamiques d'un sol argileux sous l'effet de conduites en protection intégrée contre les adv…

2015

Integrated weed management (IWM)-based cropping systems are of great interest due to their significant reduction of herbicide inputs by using a complex combination of agricultural techniques. The main objective of our work was to contribute to the environmental dimension of the multi-criteria evaluation of IWM-based cropping systems which were set up since 2000 on the experimental domain of the National Institute for Agronomical Research (INRA) to Bretenière (France). The variability of physical and hydrodynamic soil properties involved in the transfer of water through the vadose zone was studied for the 5 cropping systems present on the experimental site (1 reference cropping system and 4 …

Assessing the influence of different biochar fractions on soil structure and soil water retention: laboratory investigation on a Sicilian soil

2012

Testing the shape-similarity hypothesis between particle-size distribution and water retention for Sicilian soils

2012

Application of the Arya and Paris (AP) model to estimate the soil water retention curve requires a detailed description of the particlesize distribution (PSD) but limited experimental PSD data are generally determined by the conventional sieve-hydrometer (SH) method. Detailed PSDs can be obtained by fitting a continuous model to SH data or performing measurements by the laser diffraction (LD) method. The AP model was applied to 40 Sicilian soils for which the PSD was measured by both the SH and LD methods. The scale factor was set equal to 1.38 (procedure AP1) or estimated by a logistical model with parameters gathered from literature (procedure AP2). For both SH and LD data, procedure AP2 …

Yielding of a quartz sand from saturated to dry state

2020

The paper presents the results of an experimental work where we analyse the behaviour of an unsaturated quartz sand in a wide range of degree of saturation (from saturated to dry state). The possibility of anticipating the hydro-mechanical behaviour of the soils when they approach the dry state is fundamental in many areas. An extensive experimental program, including controlled-suction and constant water content oedometric tests, was carried out to deeply analyse the water retention behaviour and the relationship between the yield stress and suction (Loading-Collapse curve). All elasto-plastic models provide a monotonically increase of the yield stress with suction. This assumption implies…