Effect of initial water content and stress history on water-retention behaviour of mine tailings

Bending tests were conducted on specimens of unsaturated tailings from three hard rock mines to evaluate their tensile strength. Saturated samples were prepared at an initial water content, w0, of 40% and then naturally dried under ambient conditions to pre-selected degrees of saturation, Sr, which can be related to the corresponding suction using the water retention curve. The basic interpretation of the bending tests results is based on an elastic–brittle behavior. The results show how the tensile strength, σt, of unsaturated tailings varies with water content, w (and Sr). The experimental data are also used to evaluate Young’s modulus in tension, Et, and to estimate the apparent cohesion, capp, as a function of Sr. Predictive equations are also applied to estimate the values of σt of unsaturated tailings using the water retention curve.

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Investigation into water retention behaviour of deformable soils

Canadian Geotechnical Journal ◽

10.1139/cgj-2011-0409 ◽

2013 ◽

Vol 50 (2) ◽

pp. 200-208 ◽

Cited By ~ 65

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.

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Preliminary investigation on the water retention behaviour of cement bentonite mixtures

E3S Web of Conferences ◽

10.1051/e3sconf/202019503032 ◽

2020 ◽

Vol 195 ◽

pp. 03032 ◽

Cited By ~ 1

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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Responses of Soil Infiltration to Water Retention Characteristics, Initial Conditions, and Boundary Conditions

Land ◽

10.3390/land10040361 ◽

2021 ◽

Vol 10 (4) ◽

pp. 361

Author(s):

Lesheng An ◽

Kaihua Liao ◽

Chun Liu

Keyword(s):

Water Content ◽

Soil Water ◽

Water Retention ◽

Constant Pressure ◽

Pressure Head ◽

Estimation Methods ◽

Initial Water Content ◽

Initial Water ◽

Cumulative Infiltration ◽

Retention Characteristics

(1) Background: Simulation of soil water infiltration process and analysis of its influencing factors are important for water resources management. (2) Methods: In this study, the relative contributions of the soil water retention characteristics (SWRC) estimation, initial water content, and constant pressure head at upper boundary to the cumulative infiltration under various soil conditions were quantified based on the 1-D Richards’ equation and 900 scenarios. Scenario simulations were performed for two SWRC estimation methods (Jensen method and Rosetta); three different initial water contents (0.15, 0.20, and 0.25 cm3/cm3); five different constant pressure heads (0.5, 1, 2, 4, and 8 cm); and thirty soil samples with varying texture and bulk density. (3) Results: Rosetta representing the drying branch of the SWRC yielded higher simulated cumulative infiltration compared with the Jensen method representing the wetting branch of the SWRC. However, the Jensen method–predicted cumulative infiltration fluxes matched well with the measured values with a low RMSE of 0.80 cm. (4) Conclusions: The relative contribution of the SWRC estimation method to cumulative infiltration (19.1–72.2%) was compared to that of constant pressure head (14.0–65.5%), and generally greater than that of initial water content (2.2–29.9%). Findings of this study have practical significance for investigating the transport of water, nutrients, and contaminants in the unsaturated zone.

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Impact of fiber initial water content on the water retention capacity of poplar APMP fibers during the thermal drying

Wood Science and Technology ◽

10.1007/s00226-019-01148-2 ◽

2019 ◽

Vol 54 (1) ◽

pp. 227-235 ◽

Cited By ~ 1

Author(s):

Wenxuan Mo ◽

Bo Li ◽

Xin-Sheng Chai

Keyword(s):

Water Content ◽

Water Retention ◽

Water Retention Capacity ◽

Initial Water Content ◽

Retention Capacity ◽

Initial Water ◽

Thermal Drying

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Effects of Dissociation Water Retention on Pore Structure Disintegration in Hydrate Sediments

Frontiers in Energy Research ◽

10.3389/fenrg.2020.599542 ◽

2020 ◽

Vol 8 ◽

Author(s):

Liu Yang ◽

Shuo Wang ◽

Hongfeng Lu ◽

Ling Liu ◽

Rina Sa

Keyword(s):

Pore Structure ◽

Water Content ◽

Clay Minerals ◽

Water Retention ◽

Initial Water Content ◽

Initial Water ◽

Salt Minerals ◽

Water Field ◽

Two Stages ◽

Main Factor

During the depressurization process, natural gas hydrates (NGHs) decompose and release methane gas and water. Field experience shows that only 1% of the dissociation water is recovered, hindering the continuous pressure decline and further NGHs decomposition. The retention effect of the dissociation water on the pore structure is still unclear in NGHs sediments. In this paper, the hydrate sediment samples were tested for porosity, permeability, pore structure and clay minerals content, etc. The ions concentration change of solution was continuously measured using a conductivity meter to evaluate the disintegration mechanism of sediments. The results show that the pore structure of sediments tend to disintegrate under the action of dissociation water, leading to an increase in the ions concentration of dissociation water. According to the ions concentration curve, the sediment disintegration is divided into two stages. The rapid disintegration stage is mainly related to clay minerals. The slow disintegration stage is mainly related to the dissolution of soluble salt minerals. The initial water content is the main factor affecting the disintegration of the sediment skeleton. Under the condition of low initial water content, the sediment skeleton disintegrates instantaneously in dissociation water. When the initial water content exceeds 30.6–37.9%, the pore structure of sediments tends to be stable in dissociation water. Studying the effect of dissociation water on the sediment pore structure is helpful to understand the mechanism of low water production and to optimize the exploitation regime of gas hydrate.

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Influence of initial water content and strain rate on remolded yield stress in marine clay

Marine Georesources and Geotechnology ◽

10.1080/1064119x.2021.1892246 ◽

2021 ◽

pp. 1-8

Author(s):

Xiaobing Li ◽

Jianpeng Chen ◽

Xiuqing Hu ◽

Hongtao Fu ◽

Jun Wang ◽

...

Keyword(s):

Strain Rate ◽

Water Content ◽

Yield Stress ◽

Initial Water Content ◽

Marine Clay ◽

Initial Water

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Application of the Calorimetric Methods to the Characteristics of Seeds from Olives

Proceedings ◽

10.3390/foods_2020-07665 ◽

2020 ◽

Vol 70 (1) ◽

pp. 90

Author(s):

Andrzej Bryś ◽

Joanna Bryś ◽

Marko Obranović ◽

Dubravka Škevin ◽

Szymon Głowacki ◽

...

Keyword(s):

Olive Oil ◽

Water Content ◽

Cooling System ◽

Waste Product ◽

Normal Pressure ◽

Ash Content ◽

Initial Water Content ◽

Scanning Calorimetry ◽

Initial Water

The olive oil industry represents an important productive sector in the Mediterranean basin countries. Olive stone is an essential by-product generated in the olive oil extraction industries and it represents roughly 10% by weight of the olive fruit. The seeds of pickled olives are also a significant waste product. In the present study, we have investigated the possibility of the use of differential scanning calorimetry for the thermal characterization of seeds from green and black pickled olives from Croatia. The differential scanning calorimeter (DSC) with a normal pressure cell equipped with a cooling system was used to determine the thermal properties of seeds from olives. The following analyses were also performed: the determination of calorific values in a pressure bomb calorimeter, the determination of initial water content, the determination of changes of water content during drying at the temperatures of 30 °C, 50 °C and 80 °C, the determination of a percentage content of seeds mass to the mass of the whole olives, and the determination of ash content. Seeds from olives are characterized by very good parameters as a biomass. The analyzed olive seeds were characterized by low water content, low ash content, and a relatively high caloric value.

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

Scientific Reports ◽

10.1038/s41598-021-86701-5 ◽

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.

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