scholarly journals Theoretical and experimental investigations on the role of transient effects in the water retention behaviour of unsaturated granular soils

2018 ◽  
Vol 15 ◽  
pp. 54-64 ◽  
Author(s):  
Marius Milatz ◽  
Tom Törzs ◽  
Ehsan Nikooee ◽  
S. Majid Hassanizadeh ◽  
Jürgen Grabe
Keyword(s):  
Water Retention ◽  
Experimental Investigations ◽  
Granular Soils ◽  
Transient Effects ◽  
Retention Behaviour ◽  
Unsaturated Granular Soils ◽  
Water Retention Behaviour

scholarly journals Effects of pyrolysis temperature, feedstock type and compaction on water retention of biochar amended soil

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
He Huang ◽  
Narala Gangadhara Reddy ◽  
Xilong Huang ◽  
Peinan Chen ◽  
Peiying Wang ◽  
...  
Keyword(s):  
Water Retention ◽  
Pyrolysis Temperature ◽  
Chemical Properties ◽  
Bare Soil ◽  
Chicken Manure ◽  
Soil Water Retention ◽  
Amended Soils ◽  
Retention Behaviour ◽  
Water Retention Behaviour ◽  
Amended Soil

AbstractRecent studies on water retention behaviour of biochar amended soil rarely considers the effect of pyrolysis temperature and also feedstock type into account. It is well known that pyrolysis temperature and feedstock type influences the physical and chemical properties of biochar due to stagewise decomposition of structure and chemical bonds. Further, soil density, which is in a loose state (in agricultural applications) and dense (in geo-environmental engineering applications) can also influence water retention behaviour of biochar amended soils. The major objective of this study is to investigate the water retention properties of soil amended with three different biochars in both loose and dense state. The biochars, i.e. water hyacinth biochar (WHB), chicken manure biochar (CMB) and wood biochar (WB) were produced in-house at different pyrolysis temperature. After then, biochars at 5% and 10% (w/w%) were amended to the soil. Water retention behaviour (soil suction and gravimetric water content) was studied under drying and wetting cycle simulated by varying relative humidity (RH, 50–90%). Results show that 10% WHB produced at 300 °C were found to possess highest water retention. CMB is found to possess higher water retention than WB for 10% amendment ratio. In general, the addition of three biochars (at both 300 °C and 600 °C) at 10% (w/w) significantly improved the water retention at all suction ranges in both loose and dense compaction state as compared to that of the bare soil. The adsorption (wetting) and desorption (drying) capacity of biochar amended soils is constant at corresponding RH.

Thermal effects on water retention behaviour of unsaturated collapsible loess

2019 ◽  
Vol 20 (2) ◽  
pp. 756-762
Author(s):  
Qing Cheng ◽  
Chao Zhou ◽  
Charles Wang Wao Ng ◽  
Chaosheng Tang
Keyword(s):  
Thermal Effects ◽  
Water Retention ◽  
Retention Behaviour ◽  
Collapsible Loess ◽  
Water Retention Behaviour

scholarly journals Relative performance of two unsaturated soil models using different constitutive variables

2014 ◽  
Vol 51 (12) ◽  
pp. 1423-1437 ◽  
Author(s):  
Martí Lloret-Cabot ◽  
Simon J. Wheeler ◽  
Jubert A. Pineda ◽  
Daichao Sheng ◽  
Antonio Gens
Keyword(s):  
Unsaturated Soil ◽  
Unsaturated Soils ◽  
Water Retention ◽  
Experimental Tests ◽  
Experimental Results ◽  
Degree Of Saturation ◽  
State Variables ◽  
Retention Behaviour ◽  
Model Predictions ◽  
Water Retention Behaviour

Mechanical and water retention behaviour of unsaturated soils is investigated in the context of two well established coupled constitutive models, each of which is formulated in terms of a different set of stress state variables or constitutive variables. Incremental relationships describing the volume change and variation of the degree of saturation are derived for each model. These incremental relationships are used to simulate a set of experimental tests on compacted Speswhite kaolin previously reported in the literature. Six individual tests, involving isotropic compression and various forms of shearing, are analyzed in the context of the incremental forms developed, and the model predictions are then compared against experimental results. The results show that, although each constitutive model uses a different set of constitutive variables and a different scheme for coupling mechanical and water retention behaviour, the two sets of model predictions are similar and both sets provide a reasonable match to the experimental results, suggesting that both models are able to capture the relevant features of unsaturated soil behaviour, despite expressing the constitutive laws in different ways.

scholarly journals Investigation into water retention behaviour of deformable soils

2013 ◽  
Vol 50 (2) ◽  
pp. 200-208 ◽  
Author(s):  
Simon Salager ◽  
Mathieu Nuth ◽  
Alessio Ferrari ◽  
Lyesse Laloui
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Water Retention ◽  
Void Ratio ◽  
Degree Of Saturation ◽  
Retention Data ◽  
Soil Water Retention ◽  
Retention Behaviour ◽  
Wide Range ◽  
Water Retention Behaviour

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 ratio, and degree of saturation, and are expressed as a function of the total suction. The studies enable assessment of the effect of the past and present soil deformation on the shape of the curves. The void ratio exerts a clear influence on the air-entry value, revealing that the breakthrough of air into the pores of the soil is more arduous in denser states. In the plane of water content versus suction, the experimental results highlight the fact that from a certain value of suction, the retention curves corresponding to different densities of the same soil are convergent. The observed features of behaviour are conceptualized into a modelling framework expressing the evolution of the degree of saturation as a function of suction. The proposed retention model makes use of the theory of elastoplasticity and can thus be generalized into a hysteretic model applicable to drying–wetting cycles. The calibration of the model requires the experimental retention data for two initial void ratios. The prediction of tests for further ranges of void ratios proves to be accurate, which supports the adequacy of formulated concepts.

scholarly journals Local water-retention behaviour of sand during drying and wetting process observed by micro x-ray tomography with trinarisation

2016 ◽  
Vol 2 (16) ◽  
pp. 635-638 ◽  
Author(s):  
Yosuke Higo ◽  
Ryoichi Morishita ◽  
Ryunosuke Kido ◽  
Ghonwa Khaddour ◽  
Simon Salager
Keyword(s):  
Water Retention ◽  
X Ray ◽  
Retention Behaviour ◽  
Local Water ◽  
Wetting Process ◽  
Water Retention Behaviour

scholarly journals Preliminary investigation on the water retention behaviour of cement bentonite mixtures

2020 ◽  
Vol 195 ◽  
pp. 03032 ◽  
Author(s):  
Paolo Trischitta ◽  
Renato Maria Cosentini ◽  
Gabriele Della Vecchia ◽  
Gianluigi Sanetti ◽  
Guido Musso
Keyword(s):  
Water Content ◽  
Water Retention ◽  
Preliminary Investigation ◽  
Retention Behaviour ◽  
Laboratory Characterization ◽  
Wetting Fluids ◽  
Slurry Wall ◽  
Slurry Walls ◽  
High Suction ◽  
Water Retention Behaviour

Cement bentonite mixtures are often used to build slurry walls for the containment of both aqueous and non aqueous pollutants, due to their quite low hydraulic conductivity and relatively high ductility and strength. Although their hydro-mechanical behaviour in saturated conditions has been studied in the past, a part of the slurry wall is expected to rest above the groundwater level. The hydraulic characterization in unsaturated conditions is then particularly relevant to evaluate the performance of the barrier, especially when it is aimed at containing non aqueous pollutant liquids which are lighter than water (LNAPL). These non wetting fluids rest above the water table and their penetration is possible just if the barrier is unsaturated. This paper presents some preliminary results of a laboratory characterization of the water retention behaviour of three different cement bentonite mixtures. The mixtures, prepared at cement – bentonite mass ratios ranging from 4:1 to 6:1, were immersed in water and cured for 28 days. Their water retention behaviour was then determined along drying and wetting paths through different techniques, namely axis translation, filter paper and vapour equilibrium. In the high suction range, the water content – suction relationship was found to be independent of cement-bentonite ratio. In the low suction range, the water content at a given suction was found to decrease for increasing cement bentonite ratios.

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