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Numerical Analysis for Nonlinear Consolidation of Saturated Soil using Lattice Boltzmann Method

Numerical Analysis for Nonlinear Consolidation of Saturated Soil using Lattice Boltzmann Method

dimensional (1D) nonlinear consolidation analysis of saturated soil is proposed on the basis of the lattice Boltzmann method. At first, the lattice Bhatnagar-Gross- Krook (LBGK) model is used for 1D nonlinear consolidation problem of saturated soil subjected to time-dependent loading under different types of boundary conditions. In addition, the multiscale Chapman-Enskog expansion is applied to recover mesoscopic lattice Boltzmann equation to macroscopic nonlinear consolidation equation. As a result of the numerical simulation for verification, the numerical results are proved to be in good agreement with the analytical solutions available in previous literature. Finally, the numerical simulation is performed to investigate the consolidation behavior of saturated soil subjected to two different types of time-dependent loading.
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BOUNDARY ELEMENT METHOD IN PROBLEMS OF WATER-SATURATED SOIL THAT HAS CREEP PROPERTY

BOUNDARY ELEMENT METHOD IN PROBLEMS OF WATER-SATURATED SOIL THAT HAS CREEP PROPERTY

The aticle offers a calculation algorithm of the tensed & deformed state (TDS) of the water-saturated soil bases, possessing the quality of «creep», by the boundary element method (MBE). The main difference of the recom- mended modification of MBE from the generally accepted option is a possibility of forecasting the transformation of TDS of ground bases in time with account of their rheological properties.

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A robust and energy-conserving model of freezing variably-saturated soil

A robust and energy-conserving model of freezing variably-saturated soil

corresponds, according to Eqs. (23) and (24), to the water and ice contents at each level. The soil texture and thermal parameters are as in the experiment described in Sect. 7.2, whereas the saturated hydraulic conductivity is 0.3 mm s −1 . As far as the boundary condition on the mass is concerned, the bottom boundary is characterized by a no flux condition, whereas the top boundary condition varies along two simula- tions: zero flux (without rain) and constant 10 mm h −1 flux, resembling a constant precipitation (with rain). As can be seen in Fig. 9, in the first 6–7 days the behaviors with rain (solid line) and without precipitation (dotted line) are almost equal, because hydraulic conductivity is so low due to the fast ice-saturation of the first layer during cold conditions neat the beginning of the experiment. Then, when some ice is melted, hydraulic conductivity increases so that some water can infiltrate. At this point some incoming water may freeze because the soil is still cold, the ice content is increased (not shown here) and the zero-curtain effect is prolonged. As a result, infiltrating water provides energy (latent), so that tem- perature rises above 0 ◦ C earlier than in the case of without
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Seismic Site Response of Partially Saturated Soil Layers, Morteza Mirshekari

Seismic Site Response of Partially Saturated Soil Layers, Morteza Mirshekari

previous research, partial saturation has not been directly considered in the state-of-the-practice site response analysis. However, recent investigations on site response in unsaturated soils showed that this assumption might not be always reasonable (Ghayoomi and McCartney 2012). Further, the influence of the degree of saturation on seismic response analysis is often considered by incorporating the in-situ measured shear wave velocity of shallow unsaturated soil layers. However, the extent of this influence might be beyond the suction-dependency of the dynamic soil properties where the wave propagation mechanisms may vary (Yang 2006). Thus, recognizing this difference would be essential in assessing the uncertainty in projected site response where well-documented laboratory seismic site response data as well as predictive numerical models in partially saturated soils are still needed. To this end, this research project aims to fill this gap with potential goal of a more reliable evaluation of seismic hazards.
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Effects Of Deicers On Lead Mobilization In Saturated Soil

Effects Of Deicers On Lead Mobilization In Saturated Soil

In order to determine the desorption equilibrium time, solutions from each deicer of equal concentration (100 mmol/L) were prepared. For each test, 2 g of soil and 50 mL of deicer solution were mixed and shaken using an orbital shaker (150 rpm) at different mixing times (0.5, 1, 3, 8, 24 and 48hr). This part of investigation was carried out at room temperature (25°C). After each designated mixing time, the mixture was allowed to settle for 30 min and the supernatant was filtered through 0.45 µm, 150 mm ɸ Whatman membrane syringe filter. The filtrate is acidified using 1 N HNO 3 and stored in a
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Improved Model for Soil as a Two Phase Mixture Based on Smoothed Particle  Hydrodynamics (SPH)

Improved Model for Soil as a Two Phase Mixture Based on Smoothed Particle Hydrodynamics (SPH)

In order to reduce the costs of “insoluble treatment”, a numerical model to simulate the interactions between solid and liquid was developed based on the SPH method. For a seepage flow in a saturated soil, the accuracy of the volumetric water content and the absolute permeability were highly improved by the modifications. For a water absorption into dry silica sand No. 9, it was found that the soil suction makes the simulated phenomena more realistic. On the other hand, the phase permeability was thought to be not suitable for this model because it does not simply represents the drag between single fluid phase and solid phase.
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Investigating the effect of electro-osmosis on sandy soil near saturated conditions

Investigating the effect of electro-osmosis on sandy soil near saturated conditions

There have been only limited studies into the use of electro-osmosis for moving water and salt in agriculture applications. Kamel [8] investigated the elemental composition in soil and water before and after the application of EO and quantified the volumes of water moved by EO at different heights/depths and voltages. Kamel [8] stated that the application of a current density of 600 mAcm -2 and 500V was possible to extract water quantity of 200cm 3 h -1 consuming energy of 300Wh when the cathode installed at 20cm from the water surface and with applying 740 mAcm -2 and 520V the extracted water from soil was 100cm 3 h -1 consuming energy of 385Wh when the cathode placed at 40cm from water surface. Cairo [9] conducted experiments to concentrate and remove nitrates from contaminated soils. The results obtained showed that nitrate concentration in saturated soil tended to increase from anode to cathode after the application of an electrical field as the nitrate solution moved toward
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ABAQUS simulation for consolidation of saturated soft soil in two-dimensional finite region

ABAQUS simulation for consolidation of saturated soft soil in two-dimensional finite region

www.ijres.org 91 | Page elastic model, the soil is homogeneous and isotropic. In literature [5] with example 8-1 has been proved the accuracy of the numerical simulation of saturated soil consolidation that using this constitutive model. Therefore, choosing ABAQUS to this article calculation example for simulated research has certain reliability.

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Calculating pH from EC and SAR values in salinity models and SAR from soil and bore water pH and EC data

Calculating pH from EC and SAR values in salinity models and SAR from soil and bore water pH and EC data

Soil salinity can also be easily and rapidly determined by using saturated soil pastes (Rhoades et al. 1989b) or saturation paste extract (Rhoades 1982) electrical conductivity methods.[r]

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Creep response in shear of clayey geo-materials under saturated and unsaturated conditions

Creep response in shear of clayey geo-materials under saturated and unsaturated conditions

Stress relaxation and creep response in saturated soil are shown in Figure 1. Specimens S_50 were sheared to a target shear stress of 27 kPa either by controlling the displacement for stress relaxation test (Figure 1a) or by controlling the shear stress for creep test (Figure 1b). The target shear stress was about 50% of the ultimate shear strength. To model viscous response of the clay, analogue mechanical models built upon combinations of springs and dashpots, i.e. generalised Kelvin and Maxwell models, were considered. This is because these models allow capturing the creep and relaxation response using a single set of model parameters.
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Anthropogenic impact on fluvisols in German Floodplains.
Ecological processes in soils and methods of investigation

Anthropogenic impact on fluvisols in German Floodplains. Ecological processes in soils and methods of investigation

Moreover, loamy riverside sediments, non saturated and water saturated soil zones, were analysed with respect to their inorganic compounds (nutrients, heavy metals, proton concentration), organic matter (orgC, DOC, humic acids) and their capacity to buffer acid and alcaline input from the atmosphere [Meiwes, 1984; Haase and Neumeister, 1998]. While studying soil content of nutrients and heavy metals not only the actual total and water soluble con- taminant contents were determined. Using the method of sequential leaching procedures ([Zeien and Brümmer, 1989], Table 1), bonds between nutrients and heavy metals were determined to obtain an idea about the bounding me- chanisms, reactivity and the resulting mobility of each element.
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Review of Some Methods of Determining in-Situ Saturated Hydraulic Conductivity of Soil

Review of Some Methods of Determining in-Situ Saturated Hydraulic Conductivity of Soil

In-situ determination of K is important especially when the physical features of the soil system in question is to be characterized as accurately as possible. It gives more reliable values because there is minimal disturbance of the soil. It is more representative of the physical reality than the other methods [3]. In general, in-situ methods (unlike other methods) take into account the influences of both the vertical and horizontal directions and represent an average value of K. In-situ method is very important especially in highly stratified soils where the value of K measured would reflect the domination of the most permeable layer in the soil profile. Furthermore, by appropriately selecting the specific method to be used in the field, the in-situ values of the vertical and horizontal components of K could be determined independently in each layer of stratified soil [4].
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Using a sprinkler infiltrometer and the GAML model to predict moving sprinkler performance in the field

Using a sprinkler infiltrometer and the GAML model to predict moving sprinkler performance in the field

A second difficulty with implementing the SHCAZ Sprinkler Infiltrometer concept was the relatively low application rate of water onto the soil plot. Even though the Sred25_44 was selected because it had the highest application rate among the nine suitable options in Table 4-1, it still only applied water at a rate of 27mm/hr. This meant that each infiltrometer test had to run for an extended period of time - in the order of hours when the soil was very dry - before any runoff was seen and then for a further 45 minutes to generate the required runoff vs time data. There were two issues here: Firstly, it was taking far too long to complete each infiltrometer test. This was a problem in itself, but when coupled with the very uncertainty of the quality of the data (due to the wind interference), the situation was unacceptable. And secondly, the SHCAZ Sprinkler Infiltrometer was applying water at 68L/min, or 4m 3 /hour, over a fixed area of ground causing some difficulties with flooding and mud as well as being wasteful of water. (The 4m 3 /hour of water was applied over a circular area with a diameter of 13m; the soil plot being tested occupied only a small 0.75m x 0.75m area within this.) No means of collecting and recycling water had been incorporated into the SHCAZ Sprinkler Infiltrometer design and the importance of being able to capture and recirculate water during the test, such as had been done in the hydraulics laboratory, quickly became apparent in the field.
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Saturated hydraulic conductance of forest soils affected by track harvesters

Saturated hydraulic conductance of forest soils affected by track harvesters

at the problem of variability in the actual course of weather (Lhotský 2000; Ulrich et al. 2003). First of all, mainly the low air temperature (generating the change of water state) and variable weight moisture of the upper soil horizons have some natural impacts on the set of physical, hydrophysical and soil-me- chanical properties. As regards the results presented in this study, the authors were aware of the described facts, therefore, they used a high number of measur- ing points on the monitored study plots with the fo- cus on a possibility of generalization. In general, the authors are clearly aware that climatic factors remain a significant fact regarding the informative value of the application of Guelph permeameter. During the measurements with Guelph permeameter, full satu- ration does not occur because some air is trapped in a part of the porous system; this space does not con- tribute to the final conductivity value. According to Kutílek et al. (2000), repeated measurements have shown that the obtained values are realistic and do not require any subsequent correction.
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Accurate measurement of shear strength parameters, coefficient of consolidation, and compressibility can be difficult, time consuming and costly. As a result of this there is now a tendency in countries all over the world towards building up correlation equations between the above soil properties and the so-called soil indices in order to speed-up the design process. This is most pertinent in third world countries where up-to-date testing equipment are lacking together with the trained manpower needed to operate them. For the plastic, clayey soils the Atterberg limits (which are indices of soil behaviour) have been found useful for this application. This is because the measurement of the Atterberg limits requires very simple apparatuses and takes up comparatively short periods of time.
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A METHOD OF APPLYING AN ELECTRIC FIELD TO CONTAMINATED SOIL CONTAINING DEGRADING BACTERIA

A METHOD OF APPLYING AN ELECTRIC FIELD TO CONTAMINATED SOIL CONTAINING DEGRADING BACTERIA

Heavy metals are common pollutants in soils that have previously supported a wide range of industrial processes. Highly toxic species such as cadmium and arsenic pose a health hazard (Pearce, 2003), and so will have to be remediated. The process of electro migration is one choice for this task. However, the soil environment is a complex one; especially once the effects of electro kinetics are imposed (changes in the soil chemistry, such as the development of a pH gradient as discussed earlier, are particularly important). The simplicity of the basic technique then becomes vastly more complicated. There is a significant collection of research on the remediation of heavy metals, as the effects and processes will change from soil to soil. Açar and Alshawabkeh (1993) demonstrated and explained many of the effects that occur due to pH changes in soil subjected to an electric field. They describe lead and calcium removal from kaolinite and associated problems with precipitation of the contaminant at high pH near the cathode.
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Biostimulation of Oil Refinery Soils

Biostimulation of Oil Refinery Soils

the biostimulated samples versus naturally attenuated samples. Phenanthrene trends are different than the other 13 PAH trends found in the Water Phase Batch Study experiments. This may been due to many reasons, including a lag phase in the batches where the bacteria were still immobile from being kept at such cold conditions or a lack in vapourization when the lid was opened causing contaminated biostimulated samples to degrade very slowly in the first couple of days. ............................................. 64 Figure 16: Water Phase Batch Studies degradation of 4-ring aromatic benz(a)anthracene where: (a) blue triangle represent unamended contaminated soil samples and (b) red squares represent amended contaminated soil samples. The rapid decrease in benz(a)anthracene may have been due to a number of factors including biodegradation, volatilization and readsorption back on to the soils. There is an indication that biostimulation is effective in the first couple of days due to the lower concentrations of the biostimulated samples versus naturally attenuated samples. .......................................................... 65 Figure 17: Water Phase Batch Studies degradation of 4-ring aromatic chrysene where: (a) blue triangle represent unamended contaminated soil samples and (b) red squares represent amended
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Effect of treated wastewater on soil chemical and physical properties in an arid region

Effect of treated wastewater on soil chemical and physical properties in an arid region

reported that the hydraulic conductivity in silty loam was reduced in comparison with sand and sandy loam soils. This is due to the accumulation of suspended materials in the soil surface. They also stated that wastewater irrigation would increase ESP and clogging of the soil porosity. Vinten et al. (1983) also reported that the decrease in hydraulic conductivity was due to the physical and chemi- cal processes. They observed that the dissolved organic matter in wastewater even with low ESP had negative effect on hydraulic conductivity. The reduction in hydraulic conductivity is due to the retaining of the organic matters during infiltra- tion and the change of pore size distribution as a result of expansion and dispersion of soil par- ticles. Tarenitzky et al. (1999) showed that one of the important effects of adding organic matters to soil is the increase of moisture retention capacity which is due to reduction of the soil bulk density, increase of soil porosity and the specific surface area of soil particles.
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Influence of Burrow Holes in Residual Soil Slope Infiltration

Influence of Burrow Holes in Residual Soil Slope Infiltration

An initial condition was creating for each type of soils in accordance to their actual field suction measurements during dry condition. The suggested initial suction approximated to the suction corresponding to residual water content [13]. All samples taken from site was air dried first. After the sample was dry, the sample was sieve according to size of Grade VI and Grade V properties. The preparation of sample was according to in-situ or bulk density of the soil. Next, the soil was mixed with water identical the residual water content for each soil. The residual water content for each soil was determined from soil water characteristic curve for each soil.
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Modeling 3D Ex Filtration Process of a Soak Away Rain Garden

Modeling 3D Ex Filtration Process of a Soak Away Rain Garden

To mitigate the adverse impact of urbanization around the world, several best management practices, in other words, green infrastructures, have been used in a way that protect the natural hydrology of the catchment and are more beneficial to the environment [1]-[5]. Soak-away rain garden, shallow, landscaped depressions commonly located in parking lots or within small pockets in residential areas, is one of those best management practices or green infrastructures. Despite the rapid acceptance of soak-away rain gardens throughout the world by water managers and land-use planners, fundamental understandings of these green infrastructures are still at undeve- loped stage [1] [2]. Detailed hydrologic performance information and related hydrologic design guidelines of soak-away rain gardens are not currently available for many regions including Singapore. Thus, assuming per- formance to be independent of many highly dynamic conditions to which these facilities expose [1], water man- agers often adopt existing published hydrologic design guidelines, which are often represented as relationships such as a relationship between the overflow volume and surface area (as a % of catchment area) of the soak- away rain garden or the saturated hydraulic conductivity of the in-situ soil, without modifying the guidelines for local conditions. Therefore, to assist local water managers, these relationships that are specific for local condi- tions need to be established. To establish such relationships using any stormwater models that also have water quality components, such as MUSIC (model for urban stormwater improvement conceptualization), it is equally important to study the ex-filtration or draining of water into the surrounding soils, which helps in reducing the stormwater volume, of the soak-away rain garden and its relationship with the saturated hydraulic conductivity of the in-situ soil, the saturated hydraulic conductivity of the filter media (the primary soil
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