Filter leaching of salt soils of automobile roads

Globally, in arid regions, due to the irrational use of water resources for irrigating plants, salinization of soils occurs, which causes significant damage to the country's economy. In particular, recently in some regions of Uzbekistan, there has been a rise in groundwater and flooding of territories. In these areas, where the soil bases of highways contain such readily soluble salts as: NaCL, Na2SO4·10H2O, MgSO4·7H2O, MgCL2·6H2O, CaCL2·6H2O, NaHCO3, Na2CO3·10H2O, CaCO3 and CaSO4·2H2O, additional suffusion precipitation is often observed which lead to deformations of road surfaces. Additional precipitation is due to the dissolution of salt crystals upon ingress of moisture during filtration leaching. Filtration leaching of soils was carried out in the F-1M device according to the upward flow pattern. To determine the amount of leached salts during the experiment, the infiltrate was taken, its volume and mineralization were recorded. At the end of the tests, the soil was tested according to the general scheme. To assess the influence of the leaching process on the strength indices of the studied soils by the methods of consolidated and fast shear, tests of pre-leached samples were performed. When testing soils, samples were cut, pre-compacted with the same specified load, and leached for a month. In laboratory conditions, the deformation modulus was determined by performing compression experiments. In connection with a sharp change in the modulus of deformation of soils during moistening, the tests were carried out at two values of humidity: at natural and after water saturation without the possibility of swelling. The study results show that the deformation modulus of water-saturated loams satisfactorily correlates with the value of the initial porosity coefficient and decreases as a result of water saturation and leaching. The degree of decrease depends on the value of the initial deformation modulus: the higher it is, the more significant its change. The value of the coefficient of weakening of the soil structure depends on the effective average pressure. The criterion for the permissible salt content in the base of the roadbed of highways should be taken not only the value of the degree of salinity but also the change in the indicators of the mechanical properties of soils used in the design of the construction of the roadway during soaking and leaching.

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The Analysis of the Influence of Rock Massif Water Saturation on the Mine Workings Anchoring Design Parameters

E3S Web of Conferences ◽

10.1051/e3sconf/201910501027 ◽

2019 ◽

Vol 105 ◽

pp. 01027

Author(s):

Sergey Tsibaev ◽

Alexey Renev ◽

Evgenyi Kudrin ◽

Damir Zaiatdinov

Keyword(s):

Compression Strength ◽

Water Saturation ◽

Sedimentary Rocks ◽

Strength Properties ◽

Design Parameters ◽

Uniaxial Compression Strength ◽

Petrographic Composition ◽

Study Results ◽

Mine Workings ◽

Water Saturated

Here in the study results of the sedimentary rocks water saturation effect on the main parameters of anchoring of mine workings: resistance, density and installation step of the support. A series of tests of rock samples with different intervals of their water saturation has been produced. It has been established that water saturation leads to a significant change in the strength properties of sedimentary rocks, depending on their petrographic composition and the period of exposure to moisture. The relation between the degree of water saturation and a decrease in the uniaxial compression strength, between the strength of a dry sample and its tendency to decrease in strength properties under the influence of moisture, between the period of exposure to moisture and decrease in strength properties has been established. The results of the study will allow to more accurately classify the rocks of the roof according to the factors of collapse and stability, which has a significant impact on the calculation of the anchoring parameters of mine workings in water-saturated zones.

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Development of new tables of transition factors from the results of compression tests to the plate-bearing modulus

Engineering survey ◽

10.25296/1997-8650-2019-13-1-18-30 ◽

2019 ◽

Vol 13 (1) ◽

pp. 18-30

Author(s):

A. N. Trufanov

Keyword(s):

Effective Stress ◽

Linear Equations ◽

Deformation Modulus ◽

Compression Modulus ◽

Anomalous Behavior ◽

Compression Tests ◽

Starting Point ◽

Porosity Coefficient ◽

Modulus Of Deformation ◽

Soil Flow

The article is devoted to the issue of developing new tables of transition factors relating the results of compression and plate-bearing tests. As is known, the normative value of the modulus of deformation is directly determined from the most reliable plate-bearing tests. However, they are quite laborious and expensive. In contrast to plate bearing tests, compression tests are much cheaper, but they give underestimated values of the deformation modulus. In this connection, a table of transition coefficients from a compression module to a plate-bearing deformation modulus was developed (Agishev – Ignatova table). The article shows that the initial stress ranges selected for the determination of the compression and platebearing deformation modulus differ significantly. The compression module, as well as the odometric modulus of deformation in the latest version of the table, was determined in a fixed pressure range, and the plate-bearing test curve for the linear section, the starting point of which is an alternating natural effective stress. To eliminate this contradiction, when developing new tables, instead of a compression modulus, a tangential odometric modulus of deformation was used, determined for the corresponding value of the natural effective stress. The algorithm for determining new transition coefficients is described in detail. In the new tables, in addition to the porosity coefficient, the soil flow rate is also taken into account. The effect of consistency on the definition of the plate-bearing modulus and the absence of such an effect on the results of compression tests are noted. Anomalous behavior of clay of solid consistency is shown during compression tests. In addition to the tables of transition coefficients, a table of linear equations is provided for a direct transition from the results of compression tests to a plate-bearing deformation modulus. New tables are proposed to be used to determine the standard value of the modulus of soil deformation at the stage of preliminary calculations for the foundations of buildings and structures of the II and III geotechnical categories.

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EFFECT OF WHEAT STRAW INCORPORATION ON DENITRIFICATION OF N UNDER ANAEROBIC AND AEROBIC CONDITIONS

Canadian Journal of Soil Science ◽

10.4141/cjss87-079 ◽

1987 ◽

Vol 67 (4) ◽

pp. 825-834 ◽

Cited By ~ 24

Author(s):

M. S. AULAKH ◽

D. A. RENNIE

Keyword(s):

Wheat Straw ◽

Water Saturation ◽

Initial Period ◽

Fertilizer N ◽

N Losses ◽

Total Period ◽

Organic C ◽

Key Words Denitrification ◽

Straw Incorporation ◽

Water Saturated

The effects of wheat straw incorporation on denitrification, immobilization of N, and C mineralization were investigated at H2O contents of 60, 90 and 120% saturation. Incorporation of increasing levels of straw consistently increased the rate of denitrification for the first 4–8 d, followed by negligible N losses thereafter. In a total period of 96 d, the addition of 1.0% straw increased N losses from 2.5 to 10.1, and from 61.6 to 83.9 μg g−1 in the 60 and 120% water saturation treatments, respectively. The pattern of CO2-C evolved was practically identical to that of the denitrification rate for the initial period when sufficient [Formula: see text] was present. This study has confirmed that in flooded soils, high rates of denitrification will persist only when C is supplied by native or applied organic C sources, provided adequate [Formula: see text] is present. When [Formula: see text] was low, denitrification rates rapidly decreased, even with a sufficient supply of C. Immobilization of fertilizer N (50 μg N g−1 as K15NO3) was very rapid. Around 90% of the total immobilization of applied N occurred within 4 d. Incorporation of 1.0% straw increased the immobilization of fertilizer N from 8.4 to 42.8, and from 1.0 to 7.6% in the 60 and 120% water-saturated treatments, respectively. Remineralization of recently immobilized fertilizer N was observed after 32 d in the 60% saturation treatments only. Key words: Denitrification, wheat straw, mineralization of N

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Petrophysical Type Curves for Identifying the Electrical Character of Petroleum Reservoirs

SPE Reservoir Evaluation & Engineering ◽

10.2118/96718-pa ◽

2007 ◽

Vol 10 (06) ◽

pp. 711-729 ◽

Cited By ~ 3

Author(s):

Paul Francis Worthington

Keyword(s):

Water Saturation ◽

Early Stage ◽

Well Logs ◽

Log Analysis ◽

Well Log ◽

Formation Water ◽

Water Conductivity ◽

Core Data ◽

Water Saturated ◽

Petrophysical Evaluation

Summary A user-friendly type chart has been constructed as an aid to the evaluation of water saturation from well logs. It provides a basis for the inter-reservoir comparison of electrical character in terms of adherence to, or departures from, Archie conditions in the presence of significant shaliness and/or low formation-water salinity. Therefore, it constitutes an analog facility. The deliverables include reservoir classification to guide well-log analysis, a protocol for optimizing the acquisition of special core data in support of log analysis, and reservoir characterization in terms of an (analog) porosity exponent and saturation exponent. The type chart describes a continuum of electrical behavior for both water and hydrocarbon zones. This is important because some reservoir rocks can conform to Archie conditions in the fully water-saturated state, but show pronounced departures from Archie conditions in the partially water-saturated state. In this respect, the chart is an extension of earlier approaches that were restricted to the water zone. This extension is achieved by adopting a generalized geometric factor—the ratio of water conductivity to formation conductivity—regardless of the degree of hydrocarbon saturation. The type chart relates a normalized form of this geometric factor to formation-water conductivity, a "shale" conductivity term, and (irreducible) water saturation. The chart has been validated using core data from comprehensively studied reservoirs. A workflow details the application of the type chart to core and/or log data. The analog role of the chart is illustrated for reservoir units that show different levels of non-Archie effects. The application of the method should take rock types, scale effects, the degree of core sampling, and net reservoir criteria into account. The principal benefit is a reduced uncertainty in the choice of a procedure for the petrophysical evaluation of water saturation, especially at an early stage in the appraisal/development process, when adequate characterizing data may not be available. Introduction One of the ever-present problems in petrophysics is how to carry out a meaningful evaluation of well logs in situations where characterizing information from quality-assured core analysis is either unavailable or is insufficient to satisfactorily support the log interpretation. This problem is especially pertinent at an early stage in the life of a field, when reservoir data are relatively sparse. Data shortfalls could be mitigated if there was a means of identifying petrophysical analogs of reservoir character, so that the broader experience of the hydrocarbon industry could be utilized in constructing reservoir models and thence be brought to bear on current appraisal and development decisions. Here, a principal requirement calls for type charts of petrophysical character, on which data from different reservoirs can be plotted and compared, as a basis for aligning approaches to future data acquisition and interpretation. This need manifests itself strongly in the petrophysical evaluation of water saturation, a process that traditionally uses the electrical properties of a reservoir rock to deliver key building blocks for an integrated reservoir model. The solution to this problem calls for an analog facility through which the electrical character of a subject reservoir can be compared with others that have been more comprehensively studied. In this way, the degree of confidence in log-derived water saturation might be reinforced. At the limit, the log analyst needs a reference basis for recourse to capillary pressure data in cases where the well-log evaluation of water saturation turns out to be prohibitively uncertain.

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Settlement and bearing capacity of water-saturated soils of foundations of finite width under static impact

Vestnik MGSU ◽

10.22227/1997-0935.2021.4.463-472 ◽

2021 ◽

pp. 463-472

Author(s):

Zaven G. Ter-Martirosyan ◽

Armen Z. Ter-Martirosyan ◽

Ahmad Othman

Keyword(s):

Bearing Capacity ◽

Strain State ◽

Water Saturation ◽

Strength Properties ◽

Finite Width ◽

Stress Strain ◽

Linear Deformation ◽

Stress Strain State ◽

Linear And Nonlinear ◽

Water Saturated

Introduction. In case of brief exposure to static loads or dynamic loads, in conditions of absence of drainage, distribution of total stresses between the skeleton of soil and pore gas-containing water should be taken in account. The situation of the stress-strain state of the base is further complicated when we consider the degree of water-saturation of soil of the foundation (0.8 < Sr ≤ 1). The aim of the study is to pose and solve problem of the stress-strain state of a water-saturated soil massif, Including settlement and bearing capacity of a water-saturated base of a foundation of finite width, depending on the degree of water saturation of soils, taking into account the linear and nonlinear properties of the skeleton of soil and the compressibility of pore gas-containing water. Materials and methods. Henckyʼs system of physical equations are used as a calculation model to describe the relationship between deformation and stresses of soil, which takes into account the influence of the average stress on the deformation and strength properties of the soil. This system allows us to represent the linear deformation of the soil as the sum of the volumetric and shear components of the soil of this deformation. In addition allows us too to determine the deformation of the layer of soil, as part of the compressible thickness of the base of foundation with finite width under conditions of free deformations. Results. Depending on the linear and nonlinear deformation parameters, the settlement can be developed with a damped curve (S – p) and stabilize, and can be developed with a non-damped curve (S – p) and moved to the stage of progressive settlement. Conclusions. Solutions have been made for cases when the water-saturation of the base soils changes in the range of 0.8 to 1.0. It is shown that the settlement and bearing capacity of a water-saturated base significantly depends on the degree of water saturation of soils.

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Delineation of Sedimentary Facies and Groundwater-Sea Water Disposition in an Intertidal Zone of the Bay of Bengal using GPR and VES

Journal of Environmental and Engineering Geophysics ◽

10.2113/jeeg23.2.235 ◽

2018 ◽

Vol 23 (2) ◽

pp. 235-249

Author(s):

Mrinal Kanti Layek ◽

Palash Debnath ◽

Probal Sengupta ◽

Abhijit Mukherjee

Keyword(s):

Bay Of Bengal ◽

Sea Water ◽

Water Saturation ◽

Water Discharge ◽

Ground Surface ◽

Sedimentary Facies ◽

Intertidal Flat ◽

Sediment Layer ◽

Fresh Groundwater ◽

Water Saturated

A combination of geophysical study including ground penetrating radar (GPR) and vertical electrical sounding (VES) was done to identify different shallow-subsurface depositional features in an intertidal coast of the eastern parts of India, adjoining the Bay of Bengal (BoB) (Chandipur, Odisha state). The study was aimed to understand the variation of sedimentary depositional sequences, prograding to the ocean from land, as well as towards the confluence of a river channel with the BoB. Six VES points and 85 GPR traverses were taken in the intertidal flat. The data were calibrated with sedimentary sequences retrieved from simultaneously drilled boreholes in four locations. Resistivity data clearly demonstrate the subsurface sediment layer boundaries with water saturation variability, up to 156 m below ground surface (bgs). The data suggest thickening of brackish water saturated clay layers towards the southwestern part. GPR data were capable of resolving the geometry of intertidal dunes, buried palaeo-channels, erosional surface, water table, eolian deposit of sand, and washover delta depositional features which are all present in this study area. Several erosional surfaces, related to sedimentary processes, e.g., delta overwash processes, were clearly demarcated. The study also successfully identified and visualized the saline-fresh groundwater interfaces and submarine ground water discharge (SGD) zones. Consequently, based on these data, a conceptual model of the depositional and erosional history of the sedimentation of the area, as well as the coastal hydrogeological disposition, was conceived.

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A Three-Phase Study on Preflush Stage in Sandstone Acidizing: Experimental and Modeling Analysis of Evolved Carbon Dioxide in a Hydrocarbon and Aqueous Environment

SPE Journal ◽

10.2118/195897-pa ◽

2020 ◽

pp. 1-26

Author(s):

Sajjaat Muhemmed ◽

Harish Kumar ◽

Nicklaus Cairns ◽

Hisham A. Nasr-El-Din

Keyword(s):

Carbon Dioxide ◽

Water Saturation ◽

Injection Rate ◽

Mineral Dissolution ◽

Carbonate Mineral ◽

Carbonate Minerals ◽

Oil Saturation ◽

The Core ◽

Three Phase ◽

Water Saturated

Summary Limited studies have been conducted in understanding the mechanics of preflush stages in sandstone-acidizing processes. Among those conducted in this area, all efforts have been directed toward singular aqueous-phase scenarios. Encountering 100% water saturation (Sw) in the near-wellbore region is seldom the case because hydrocarbons at residual or higher saturations can exist. Carbonate-mineral dissolution, being the primary objective of the preflush stage, results in carbon dioxide (CO2) evolution. This can lead to a multiphase presence depending on the conditions in the porous medium, and this factor has been unaccounted for in previous studies under the assumption that all the evolved CO2 is dissolved in the surrounding solutions. The performance of a preflush stage changes in the presence of multiphase environments in the porous media. A detailed study is presented on the effects of evolved CO2 caused by carbonate-mineral dissolution, and its ensuing activity during the preflush stages in matrix acidizing of sandstone reservoirs. Four Carbon Tan Sandstone cores were used toward the purpose of this study, of which two were fully water saturated and the remaining two were brought to initial water saturation (Swi) and residual oil saturation to waterfloods (Sorw) before conducting preflush-stage experiments. The preflush-stage fluid, 15 wt% hydrochloric acid (HCl), was injected in the concerning cores while maintaining initial pore pressures of 1,200 psi and constant temperatures of 150°F. A three-phase-flow numerical-simulation model coupled with chemical-reaction and structure-property modeling features is used to validate the conducted preflush-stage coreflood experiments. Initially, the cores are scanned using computed tomography (CT) to accurately characterize the initial porosity distributions across the cores. The carbonate minerals present in the cores, namely calcite and dolomite, are quantified experimentally using X-ray diffraction (XRD). These measured porosity distributions and mineral concentrations are populated across the core-representative models. The coreflood effluents’ calcium chloride and magnesium chloride, which are acid/carbonate-mineral-reaction products, as well as spent-HCl concentrations were measured. The pressure drop across the cores was logged during the tests. These parameters from all the conducted coreflood tests were used for history matching using the numerical model. The calibrated numerical model was then used to understand the physics involved in this complex subsurface process. In fully water-saturated cores, a major fraction of unreacted carbonate minerals still existed even after 40 pore volumes (PV) of preflush acid injection. Heterogeneity is induced as carbonate-mineral dissolution progresses within the core, creating paths of least resistance, leading to the preferential flow of the incoming fresh acid. This leads to regions of carbonate minerals being untouched during the preflush stimulation stage. A power-law trend, P = aQb, is observed between the stabilized pressure drops at each sequential acid-injection rate vs. the injection rates, where P is the pressure drop across the core, Q is the sequential flow rate, and a and b are constants, with b < 1. An ideal maximum injection rate can be deduced to optimize the preflush stage toward efficient carbonate-mineral dissolution in the damaged zone. An average of 25% recovery of the oil in place (OIP) was seen from preflush experiments conducted on cores with Sorw. In cores with Swi, the oil saturation was reduced during the preflush stage to a similar value as in the cores with Sorw. The oil-phase-viscosity reduction caused by CO2 dissolution in oil and the increase in saturation and permeability to the oil phase resulting from oil swelling by CO2 are inferred as the main mechanisms for any additional oil production beyond residual conditions during the preflush stage. The potential of evolved CO2, a byproduct of the sandstone-acidizing preflush stage, toward its contribution in swelling the surrounding oil, lowering its viscosity, and thus mobilizing the trapped oil has been depicted in this study

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Evaluating the Effectiveness of a Mine Tailing Cover

Hydrology Research ◽

10.2166/nh.1992.0014 ◽

1992 ◽

Vol 23 (3) ◽

pp. 193-208 ◽

Cited By ~ 1

Author(s):

Roger B. Herbert

Keyword(s):

Hydraulic Conductivity ◽

Unsaturated Flow ◽

Water Saturation ◽

Pressure Head ◽

Mine Tailing ◽

Clay Layer ◽

Cover Design ◽

Water Saturated ◽

Parameter Values ◽

Maximal Reduction

This study presents a method for evaluating the effectiveness of a mine tailing cover. The cover is designed with a 0.5 m layer of clay covered by a 1.5 m layer of glacial till; full water saturation of the clay layer is assumed to be necessary for the maximal reduction of oxygen transport through the cover. The evaluation of cover effectiveness is based on: 1) the reduction of leachate production, and 2) the ability of the clay layer to remain water saturated and avoid cracking. Using 1990 precipitation data, the numerical model SUTRA simulates unsaturated flow in the cover, with results interpreted in terms of pressure head variations and vertical discharge from the cover. The modeling results indicate that this cover design would adequately reduce leachate production from a tailing deposit. In addition, the water saturation of the clay layer remains above its plastic limit during a simulated year of normal recharge conditions; it is therefore not likely that the clay layer would crack. A sensitivity analysis with different hydraulic parameter values is performed, and shows that leachate production is most sensitive to clay hydraulic conductivity, while the water saturation of the clay layer is sensitive to both clay hydraulic conductivity and till porosity.

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Thermal Infrared Radiation and Laser Ultrasound for Deformation and Water Saturation Effects Testing in Limestone

Remote Sensing ◽

10.3390/rs12244036 ◽

2020 ◽

Vol 12 (24) ◽

pp. 4036

Author(s):

Alexander Kravcov ◽

Elena Cherepetskaya ◽

Pavel Svoboda ◽

Dmitry Blokhin ◽

Pavel Ivanov ◽

...

Keyword(s):

Water Saturation ◽

Structural Features ◽

Technical Condition ◽

Natural Stone ◽

Laser Ultrasound ◽

Engineering Structures ◽

Quartz Content ◽

Saturation Effects ◽

Water Saturated ◽

Stone Structures

During the operation of engineering structures made of natural stone, for industrial and civil purposes, an important parameter in monitoring their technical condition is the assessment of their reliability and safety under the influence of various external influences. In this case, high-quality monitoring of the stress–strain state of natural stone structures, its physical, mechanical and filtration properties, as well as internal structural features is necessary to study the possibility of replacing individual elements of objects that have lost their original characteristics. To assess the state of geomaterials, this article proposes using a complex of introscopic methods, including infrared radiometry and laser-ultrasound structuroscopy. An important aspect is the calculation based on the Green–Christoffel equation of the velocity of a quasi-longitudinal wave in limestone consisting of densely packed, chaotically oriented calcite grains with a small quartz content. For the first time, using laser-ultrasonic structuroscopy and standard methods for determining open porosity, both total and closed porosity were determined. This allowed us to find the values of specific heat capacities of dry and water-saturated samples. The obtained values are used to find the ratio of changes in the temperature of dry and water-saturated samples at the same stress values. The results obtained demonstrate the need to take into account changes in the intensity of thermal radiation of limestone with different moisture content under conditions of uniaxial compression, when identifying changes in the stress state of elements of stone structures in real conditions.

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Calculation of a beam on an inhomogeneous basis

MATEC Web of Conferences ◽

10.1051/matecconf/201825104023 ◽

2018 ◽

Vol 251 ◽

pp. 04023

Author(s):

Nikolaj Atarov

Keyword(s):

Numerical Calculation ◽

Power Law ◽

Modulus Of Elasticity ◽

Strain Energy ◽

Deformation Modulus ◽

Bending Moment ◽

System Of Differential Equations ◽

Total Potential ◽

Modulus Of Deformation ◽

Symmetric Load

The questions of analytical calculating the beam on the base with the modulus of deformation (modulus of elasticity), which is changed by thickness of the layer by power law, was deals in the article. The purpose of work was receiving finite expressions for reactive pressure of the basе on a beam and internal efforts in a beam when using model of the base with two characteristics (coefficient of subgrade resistance). A system of differential equations second-order with respect to the displacements of points the surface of a layer with a continuously changing modulus of elasticity was obtained based on the minimum of the total potential strain energy. The calculation of the rigid beam on the base on the action of the symmetric load was performed and the formulas for the reactive pressures of the base were got. Numerical calculation is executed and the analysis of influence of change of the module of deformation of a layer by the amount of reactive pressure and the bending moment in a beam was given. It is shown that with increase in the module of deformation on layer thickness the basе with two characteristics on nature of work is approaching vinklerovsky.

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