Search results for " SOIL"
showing 10 items of 774 documents
Characterization of gas flow through low-permeability claystone: laboratory experiments and two-phase flow analyses
2014
For the characterization of gas migration through a low-permeability clay host rock for deep underground repositories, a comprehensive understanding of the relevant phenomena of gas and fluid flow through low-permeability clay is required. The National Cooperative for the Disposal of Radioactive Waste (Nagra) in Switzerland has developed a comprehensive programme to characterize gas flow in low-permeability Opalinus Clay through laboratory tests and detailed numerical analyses for developing appropriate constitutive models. Laboratory tests were performed on cores by two different laboratories, the Laboratory for Soil Mechanics at EPFL and the Department of Geotechnical Engineering and Geos…
La resistenza di interfaccia calcestruzzo poroso-terreni a grana fina per il consolidamento di pendii mediante trincee drenanti profonde
2022
Le trincee drenanti profonde rappresentano uno dei metodi più efficaci per la mitigazione del rischio da frana, in pendii con falda idrica. Esse sono realizzate mediante pannelli o pali secanti. Il riempimento è costituito di calcestruzzo poroso o materiale granulare. Se le trincee sono adeguatamente “innestate” nel terreno stabile e il materiale di riempimento ha sufficiente resistenza e rigidezza come il calcestruzzo poroso, si ha ulteriore in-cremento di resistenza a taglio per effetto shear keys, oltre a quello derivante dalla riduzione delle pressioni in-terstiziali. L’incremento di resistenza è dovuto sia alla resistenza all’interfaccia calcestruzzo–terreni sia a quella intrinseca del…
Modelling landslides in unsaturated slopes subjected to rainfall infiltration using material point method
2016
This paper presents a dynamic fully coupled formulation for saturated and unsaturated soils that undergo large deformations based on material point method. Governing equations are applied to porous material while considering it as a continuum in which the pores of the solid skeleton are filled with water and air. The accuracy of the developed method is tested with available experimental and numerical results. The developed method has been applied to investigate the failure and post-failure behaviour of rapid landslides in unsaturated slopes subjected to rainfall infiltration using two different bedrock geometries that lie below the top soil. The models show different failure and post-failur…
Phosphorous removal from human urine using lateritic soil
2023
Phosphorous (P) in human urine is among the macronutrients in municipal wastewater that has exacerbated eutrophication of water bodies. Adsorption of P from wastewater using cost effective, environmentally friendly, and efficient adsorbents is considered as an attractive method that can both mitigate the eutrophication problem and augment the already strained P reserves. In the present study the adsorption capacity and structural properties of lateritic soil (LS), the adsorbent for removal of P from human urine, was investigated using XRF, SEM, TGA and FTIR techniques. Batch adsorption experiments were conducted to determine various adsorption parameters such as the sorption rates, the conc…
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 …
Evaluation Of The Soil Moisture Agricultural Drought Index (SMADI) And Precipitation-Based Drought Indices In Argentina
2020
Abstract. Agricultural drought is one of the most critical hazards with regard to intensity, severity, frequency, spatial extension and impact on livelihoods. This is especially true for Argentina, where agricultural exports can represent up to 10% of gross domestic product (GDP), and where drought events for 2018 led to a decrease of nearly 0.5% of GDP. In this work, we investigate the applicability of the Soil Moisture Agricultural Drought Index (SMADI) for detection of droughts in Argentina, and compare its performance with the use of two well-known precipitation-based indices: the Standardized Precipitation Index (SPI) and the Standardized Precipitation- Evaporation Index (SPEI). SMADI …
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…
Magnetic Susceptibility in the Soils Along Communication Routes in the Town of Opole
2019
Magnetic susceptibility measurements were taken in eight selected streets of Opole, with diversified vehicle traffic intensity. The experiment surfaces were marked on every street, with two separate zones: A – a strip directly adjacent to the road and B – a strip 1 m away from the road edge. The carried out research indicated considerable influence of communication-generated pollution, with simultaneous influence of other local emission sources. The relation of magnetic anomalies was indicated, which may be the result of ferromagnetic materials aggregation, originating mainly from combustion processes. The road structure, including the surface condition, the main construction material and s…
Hydro-mechanical behaviour of a sandy silt from a river embankment
2020
The paper presents the results of an experimental campaign aimed at characterizing the hydro-mechanical behaviour of a sandy silt from a river embankment. Due to continuous river level fluctuations and changing climatic and environmental conditions, flood embankment materials experience frequent variations in degree of saturation and suction values. Such variations strongly impact the earthwork performance both in terms of seepage and stability conditions. For these reasons, a detailed characterization of the material behaviour in unsaturated conditions was carried out. Experiments were designed in order to highlight the response of the involved soil in terms of changes in matric suction an…
Accuracy of Saturated Soil Hydraulic Conductivity Estimated from Numerically Simulated Single‐Ring Infiltrations
2019
The single-ring pressure infiltrometer (PI) method is widely used to determine saturated soil hydraulic conductivity, K s , directly in the field. The original and still most common way to analyze the data makes use of the steady-state model developed by the Canadian School in the 90s and two (two-ponding-depth, TPD, approach) or more (multiple-ponding-depth, MPD, approach) depths of ponding. The so-called Wu method based on a generalized infiltration equation allows analysis of the transient infiltration data collected by establishing a single ponding depth of water on the infiltration surface. This investigation, making use of simulated infiltration runs for initially unsaturated sand to …