DOCSLIB.ORG

Hydraulic Conductivity of Gravelly Soils with Various Fine-Grained Content

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Hydraulic Conductivity of Gravelly Soils with Various Fine-Grained Content Hydraulic Conductivity of Gravelly Soils with Various Fine-Grained Content Yi Zhou 1,2 and Zhenbin Peng1,2 1 School of Geosciences and Info-Physics, Central South University, Changsha, 410083, China 2 Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring, Central South University, Changsha, 410083, China e-mail: [email protected] ABSTRACT Gravelly soils with a certain clay content has proven to be a good performance anti-seepage material. However, there are many factors affecting the permeability coefficient of gravel soil. For example, the content of fine particles, properties of fines and compactive effort. Laboratory experiments are conducted to study the effect of above factors. The hydraulic conductivities of soils with different fines, coarse grains and mix ratios are measured using the variable water head permeability tests. The test results show that the permeability coefficient of gravelly soils decreases linearly with the increase of fine particle content and then tends to be stable. The permeability coefficient of gravelly soil decreases with the increase of fine material liquid limit and plasticity index.The permeability coefficient of gravelly soils with clay as fine material decreases in the form of exponential function with the increase of compaction effort. KEYWORDS: Gravelly soil; Optimal moisture content; Hydraulic conductivity; Compactive effort INTRODUCTION Gravelly soils can solve the problems of low strength, easy settlement, deformation and cracking of [1-2] clay as impervious material due to its high density, strength and low compressibility after rolling . In [3-5] recent years, it has been widely used as anti-seepage material for core wall of earth-rockfill dam . However, because of the wide range of particle gradation of soil materials, and most of them have the - 1053 - Vol. 24 [2019], Bund. 04 1054 characteristics of non-uniformity, instability and discontinuity, the compacted gravel soil used as core wall filling material in earth-rockfill dam project may can not meet the technical requirements that the permeability coefficient of the impervious core wall is less than 1×10-5 cm/s due to poor gradation. Gravelly soils with a certain clay content have been proved to be a kind of engineering performance, [6] economical and practical anti-seepage material. Xibao Rao through outdoor test demonstrate that under the condition of the same compaction degree, the permeability is not only related to the content of [7] p5, but also related to the content of 0.1mm particles and clay. Ting Yu believes that when the fine particle content of natural gravel soil is small and the anti-seepage and impermeability can not meet the requirements, it is an effective measure to eliminate coarse particles to adjust the gradation of gravel soil and improve its performance. In addition, the drying shrinkage of gravel soil is smaller than that of [8] clay , and the compression modulus is higher than that of clay, which is superior to clay in reducing the horizontal cracks in the core wall. In summary, the strength and deformation performance of gravel impervious material is much better than that of clay. Replacing clay with gravel soil has great advantages and broad engineering application prospects in economy and engineering performance. For soil impervious materials, fine particles usually play a decisive role. For example, the famous Hazeng formula indicates that the permeability coefficient of soil is closely related to D10. Therefore, the content of fine particles should be the key to control the permeability coefficient. In this paper, according to the key factors affecting the anti-seepage performance of gravel soil, the effects of fine particle content, fine physical properties and compaction work on the anti-seepage performance of gravel soil are analyzed. MATERIALS AND METHODS Gradation design and calculation of optimal moisture content It is generally necessary to compaction gravel soil when it is used as impervious material. In order to save the cost and ensure the anti-seepage effect, the test is generally compacted under the optimal moisture content. The gravelly soil with different fine grain content was tested, and the gradation design was shown in Figure 1. Vol. 24 [2019], Bund. 04 1055 Figure 1: Gradation curve of soil sample The standard compaction of soil is carried out by light compaction instrument, and the relationship between soil water content and dry density under various gradation is measured, and the maximum dry density and optimal water content are obtained as shown in figure 2.From the measured results, the relationship between the optimal moisture content and the fine grain content can be estimated by the following formula: ω=ωa×η+ωb×（1-η） In the formula,ωa is the optimal moisture content of fine grain group, ωb is the water content of gravel group, andηis the content of fine grain. Figure 2: Compaction curves for gravel soils Vol. 24 [2019], Bund. 04 1056 Experimental scheme The fine particle content, the physical properties of fine particles and the degree of compaction all have great influence on the permeability coefficient, so the experiments are designed and studied according to the above factors. In order to study the effect of fine particle content on the permeability coefficient of gravel soil, silty clay and bentonite with different mass ratio (10% to 100%) were mixed with coarse sand. The test results are shown in figure 3. In order to study the effect of fine physical properties on the permeability coefficient of gravel soil, five different fine materials (as shown in Table 1) were tested. The experiments carried five kinds of fine-grained soils with pure fine-grained materials, 30% and 40% fine-grained materials mixed with coarse sand (the particle size was 1 to 2 mm). The test results are shown in Table 2. In order to study the influence of compaction effect on the permeability coefficient of gravelly soil, 8, 16, 24and 32 hit / layer were used to compacted soil sample of pure fine-grained soil and gravelly soil, respectively.(Corresponding to the unit volume impact work 295.8, 591.6, 887.4 and 1183.2k J/m3, respectively) , and the permeability coefficient of the soil sample was measured. All the soil samples in the experiment were compacted with the same compaction work (591.6 J/m3) under the optimal moisture content. The soil samples are cylindrical samples with diameter 60mm and height 50mm. The permeability coefficient of saturated soil sample is measured by variable head permeability test. There are five kinds of fine materials used in the test, and their basic physical properties are shown in Table 1. The coarse-grained materials used are coarse sand (with a particle size of 1 to 2 mm) and coarse-grained soil with continuous gradation (the gradation is shown in figure 1). Table 1: Physical properties of fines Maximum dry Optimal moisture Liquid limit Plastic limit Relative density density/(g.cm-3) content (%) (%) (%) (g.cm-3) 1.32 0.34 50.5 28.2 2.73 1.51 0.35 67.8 33 2.75 1.55 0.26 33.7 23.1 2.66 1.78 0.15 25.5 17.5 2.68 1.88 0.14 27.5 14.8 2.73 RESULTS AND DISCUSSION Analysis of the influence of fine-grained content The analysis of the influence of fine-grain content can be seen in figure 3, when silty clay is used as fine material, when the fine particle content increases from 10% to 40%, the permeability coefficient decreases sharply, reaches the minimum near 40%, and then increases slowly. The reason Vol. 24 [2019], Bund. 04 1057 for the above change in the permeability coefficient is that when the fine particle content is less than 40%, with the increase of the fine particle content, the gravel soil transitions from the skeleton pore structure to the skeleton dense structure. The more the fine particle content is, the smaller the pore diameter is. The seepage path will become tortuous, these changes will affect the seepage velocity and reduce the permeability coefficient. When the fine particle content is more than 40%, the permeability coefficient increases slightly, because the gravel soil is in the dense suspension [9-10] structure . As the content of fine particles increases, the compaction becomes more difficult. The coarse aggregate does not form a skeleton and only plays a role in reducing the effective permeation area. Therefore, when the fine particles are increased and the coarse particles are reduced, the soil permeability coefficient will be Increased, but the growth rate is not large. At the same time, it can be found that when the fine clay is silty clay, the 10% fine particle content can not guarantee that the soil permeability coefficient is less than 1×10-5cm/s. Similarly, the bentonite and the coarse-grained soil corresponding to the gradation in fig. 1 are mixed according to the mass ratio, which is similar to that of silty clay as fine-grained material, and the permeability coefficient tends to be stable when the bentonite content is more than 30%. The permeability coefficient of pure fine-grained soil is close to that of pure fine-grained soil. Figure 3: Relationship between hydraulic conductivity and fines Analysis of the influence of physical Properties of Fine particles The plastic limit and liquid limit reflect the change process of the moisture content of the weakly bound water (diffusion layer) in clay. In theory, the higher the liquid-plastic limit of fine-grained soil is, the stronger its ability to adsorb water is, so the viscous effect of permeable flow between pores is more obvious, so the smaller the permeability coefficient is. Vol. 24 [2019], Bund. 04 1058 Table 2: Results of permeability of soils with various fines Types of pure soil of fine containing 40% containing 30% fine fine-grained soils grain fine particles particles residual soil 3.5X10-7 4.5X10-7 4.3X10-5 -7 -7 -6 red clay 1.5X10 2.1X10 1.0X10 -7 -5 -4 dolomite 4.0X10 6.1X10 1.8X10 silty clay 4.9X10-5 5.3X10-5 1.7X10-4 silt 3.5X10-7 6.8X10-5 2.4X10-4 The relationship between permeability coefficient and liquid plastic limit of fine grain material is shown in Fig.
Load more

Recommended publications
  • Infiltration, Permeability, Liquid Limit and Plastic Limit of Soil (IJIRST/ Volume 4 / Issue 6 / 003)
    IJIRST –International Journal for Innovative Research in Science & Technology| Volume 4 | Issue 6 | November 2017 ISSN (online): 2349-6010 Infiltration, Permeability, Liquid Limit and Plastic Limit of Soil S. Andavan Vegi Varun Assistant Professor Student Department of Civil Engineering Department of Civil Engineering Saveetha School of Engineering, Saveetha University, Saveetha School of Engineering, Saveetha University, Chennai. India Chennai. India Abstract Precipitation falling on the soil wets down and it starts penetrating into the soil. Water stores to the formal level the soil moisture deficiency excess moving down by the gravity force through percolation or seepage to build up the water table. The water is driven into the porous soil by force of gravity. First the water wets soil grain sand then the extra water moves down due to gravitational force. The rate at which a soil absorbing the water in a given time is called infiltration rate and it depends on soil characteristics such as hydraulic conductivity, soil structure, vegetation cover. The infiltration plays an important role in generation of runoff volume, if infiltration rate of given soil is less than intensity of rainfall then it results in either accumulation of water on soil surface or in runoff. The different soil conditions affect the soil infiltration rate. Compacted soils due to movement of agricultural machines have a low infiltration rate which is prone to runoff generation. Infiltration will be maximum at the beginning and it decays exponentially and gets a constant value. There will be a decrease in infiltration rate day by day due to the saturation of the soil where as on the first day the infiltration rate will be more because soil will be dry in condition.
    [Show full text]
  • Consolidation and Permeability Behavior of High Porosity Baltic Seabed Sediments
    University of Rhode Island DigitalCommons@URI Open Access Master's Theses 1994 Consolidation and Permeability Behavior of High Porosity Baltic Seabed Sediments Ajoykumar Ag University of Rhode Island Follow this and additional works at: https://digitalcommons.uri.edu/theses Recommended Citation Ag, Ajoykumar, "Consolidation and Permeability Behavior of High Porosity Baltic Seabed Sediments" (1994). Open Access Master's Theses. Paper 916. https://digitalcommons.uri.edu/theses/916 This Thesis is brought to you for free and open access by DigitalCommons@URI. It has been accepted for inclusion in Open Access Master's Theses by an authorized administrator of DigitalCommons@URI. For more information, please contact [email protected]. CONSOLIDATION AND PERMEABILITY BEHAVIOR OF HIGH POROSITY BALTIC SEABED SEDIMENTS BY AJOYKUMAR AG A THESIS SUBMITrED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN OCEAN ENGINEERING UNIVERSITY OF RHODE ISLAND 1994 MASTER OF SCIENCE THESIS OF AJOYKUMAR AG APPROVED: Thesis Committee Major Professor_ __..,,...._....""""""'"""""""~"'"""""''----=--=----=--- UNIVERSITY OF RHODE ISLAND 1994 ABSTRACT The consolidation and permeability characteristics of high porosity surficial sediments from the Coastal Benthic Boundary Layer (Naval Research Laboratory) Special Research Program test site in the EckemfOrde Bay Baltic Sea were studied using a backpressured, constant rate of deformation (CRD) consolidation and permeability testing system driven by flow pumps The silty clay sediments from the Baltic test site are characterized by high void ratios (above 6), large organic content and dissolved or free methane gas bubbles. The high organic content (up to 17%) influences several of the unique features of these sediments including high water contents (up to 500%; porosities up to 93%), high consistency limits and high compressibility.
    [Show full text]
  • Evaluation of Hydraulic Conductivity
    EVALUATION OF HYDRAULIC CONDUCTIVITY METHODS USING LABORATORY, FIELD AND EMPIRICAL EQUATION – A CASE STUDY IN MOJO RIVER STREAM BED SADIK ABDULJELIL KEDIR MASTER OF SCIENCE ADDIS ABABA SCIENCE AND TECHNOLOGY UNIVERSITY FEBRUARY 2018 EVALUATION OF HYDRAULIC CONDUCTIVITY METHODS USING LABORATORY, FIELD AND EMPIRICAL EQUATION – A CASE STUDY IN MOJO RIVER STREAM BED By SADIK ABDULJELIL KEDIR A Thesis Submitted to The Department of Civil Engineering for the Partial Fulfilment of the Requirements for the Degree of Master of Science in Civil Engineering (Geotechnical Engineering) ADDIS ABABA SCIENCE AND TECHNOLOGY UNIVERSITY FEBRUARY 2018 Declaration I hereby declare that this thesis entitled “Evaluation of Hydraulic Conductivity Methods Using Laboratory, Field And Empirical Equation – A Case Study in Mojo River Stream Bed” was composed by myself, with the guidance of my advisor, that the work contained herein is my own except where explicitly stated otherwise in the text, and that this work has not been submitted, in whole or in part, for any other degree or processional qualification. Name: Signature, Date: ii Approval Page This Msc thesis Proposal entitled “Evaluation of Hydraulic Conductivity Methods Using Laboratory, Field And Empirical Equations – A Case Study in Mojo River Stream Bed” has been approved by the following examiners in partial fulfilment of the requirement for the degree of Master of Science in Geotechnical Engineering. Date of Defense: February 2, 2018 Principal Advisor 1. Dr. Argaw Asha ______________ ____________ Signature Date Members of the Examining board: 1) Dr. Daniel Teklu 28/05/2018 Principal Examiner Signature Date 2) Dr. Avinash M. Potdar _______________ _____________ Co. Examiner Signature Date 3) Dr.
    [Show full text]
  • Hydraulic Conductivity in Layered Saturated Soils Assessed Through a Novel Physical Model 
    Hydraulic conductivity in layered saturated soils assessed through a novel physical model Eduardo Dulcey-Leal a, Fausto Molina-Gómez b & Lenin Alexander Bulla-Cruz c a Facultad de Estudios a Distancia, Universidad Militar Nueva Granada, Colombia. [email protected] b Facultad de Ingeniería, Universidad Militar Nueva Granada, Colombia. [email protected] c Facultad de Ingeniería, Universidad Nacional de Colombia, Colombia. [email protected] Received: April 27th, 2017. Received in revised form: November 1rd, 2017. Accepted: February15th, 2018. Abstract This paper introduces a novel physical model for measuring the hydraulic conductivity of granular materials in saturated conditions. An innovation in the location of the device’s piezometers allows the device to be used to assess the permeability of layered soils for both parallel and perpendicular flows. The model’s square section construction makes soil compaction easy. Design methodology took issues of construction, calibration and implementation into account. Permeability coefficients in directions parallel and perpendicular to soil stratification were measured, and Student’s t-test was performed for the relation of experimental results and existing numerical correlations. Analysis of the results shows that the physical model can replicate seepage in layered soils with parallel and perpendicular flows as occurs in field. Furthermore, it was found that it is possible to validate the experimental calibration data by use of statistical techniques. Keywords: equivalent permeability coefficient; seepage; statistical analysis; t-test. Estimación de la conductividad hidráulica en suelos saturados estratificados mediante un nuevo modelo físico Resumen Este documento presenta un modelo físico novedoso que permite medir la conductividad hidráulica en materiales granulares saturados.
    [Show full text]
  • Simulation-Based Solutions Reducing Soil and Groundwater Contamination from Fertilizers in Arid and Semi-Arid Regions: Case Study the Eastern Nile Delta, Egypt
    International Journal of Environmental Research and Public Health Article Simulation-Based Solutions Reducing Soil and Groundwater Contamination from Fertilizers in Arid and Semi-Arid Regions: Case Study the Eastern Nile Delta, Egypt Ismail Abd-Elaty 1, Lorenzo Pugliese 2 , Martina Zelenakova 3,* , Peter Mesaros 4 and Abdelaziz El Shinawi 5 1 Department of Water and Water Structures Engineering, Faculty of Engineering, Zagazig University, Zagazig 44519, Egypt; [email protected] 2 Department of Agroecology, Aarhus University, 8830 Tjele, Denmark; [email protected] 3 Department of Environmental Engineering, Faculty of Civil Engineering, Technical University of Kosice, 04200 Kosice, Slovakia 4 Department of Construction Technology and Management, Faculty of Civil Engineering, Technical University of Kosice, 04200 Kosice, Slovakia; [email protected] 5 Environmental Geophysics Lab (ZEGL), Geology Department, Faculty of Science, Zagazig University, Zagazig 44519, Egypt; [email protected] * Correspondence: [email protected] Received: 7 November 2020; Accepted: 12 December 2020; Published: 15 December 2020 Abstract: Intensive agriculture requires increasing application of fertilizers in order to sustain food production. Improper use of these substances in combination with increasing seawater intrusion results in long-term and nonpoint soil and groundwater contamination. In this work, a 3-D groundwater and solute transport numerical model was created to simulate the effect of excessive fertilizers application along the Bahr El Baqar drain system, in the eastern Nile Delta, Egypt. The geotechnical properties of the soils, hydrologic parameters, and unconfined compressive strength were determined at different sites and used as input parameters for the model. Model results showed that silty clay soils are able to contain the contaminations and preserve the groundwater quality.
    [Show full text]
  • Unit 5 - Week4:Soil Permeability
    24/07/2018 Geology and Soil Mechanics - - Unit 5 - Week4:Soil Permeability X [email protected] ▼ Courses » Geology and Soil Mechanics Announcements Course Ask a Question Progress Mentor Unit 5 - Week4:Soil Permeability Course outline Assignment 4 The due date for submitting this assignment has passed. Due on 2016-02-26, 23:55 IST. How to access the portal Submitted assignment Week Tick True or False against the following statements 1:Engineering geology of soils and Index 1) Soil permeability coefficient is directly proportional to void ratio of soil medium. 1 point properties of soils True False Week 2:Classification No, the answer is incorrect. of soils, soil Score: 0 structure and Accepted Answers: clay mineralogy False Week 3:Soil 2) Soil permeability is mostly dependent on Darcy’s Law. 1 point Compaction True Week4:Soil False Permeability No, the answer is incorrect. Module 16 - Score: 0 Permeability Accepted Answers: Module 17 - True Permeability 3) Turbulent flow can occur when water flows through soil pores. 1 point Module 18 - Permeability True Module 19 - False Permeability & Seepage No, the answer is incorrect. Module 20 - Score: 0 Seepage Accepted Answers: Quiz : True Assignment 4 4) Soil permeability coefficient is directly related to viscosity coefficient of the medium 1 point Solution For Assignment 4 True False Week5:Seepage and In-situ No, the answer is incorrect. stresses Score: 0 Accepted Answers: Week6:In situ stresses and False Consolidation 5) Falling head test is for sandy type of soil 1 point https://onlinecourses.nptel.ac.in/noc16_ce01/unit?unit=32&assessment=34 1/6 24/07/2018 Geology and Soil Mechanics - - Unit 5 - Week4:Soil Permeability Week True 7:Consolidation False No, the answer is incorrect.
    [Show full text]
  • 48. Variations in Sediment Physical Properties and Permeability of Mud-Volcano Deposits from Napoli Dome and Adjacent Mud Volcanoes1
    Robertson, A.H.F., Emeis, K.-C., Richter, C., and Camerlenghi, A. (Eds.), 1998 Proceedings of the Ocean Drilling Program, Scientific Results, Vol. 160 48. VARIATIONS IN SEDIMENT PHYSICAL PROPERTIES AND PERMEABILITY OF MUD-VOLCANO DEPOSITS FROM NAPOLI DOME AND ADJACENT MUD VOLCANOES1 Achim Kopf,2 M. Ben Clennell,3 and Angelo Camerlenghi4 ABSTRACT Active mud volcanoes on the Mediterranean Ridge accretionary prism were sampled during Bannock Cruises 88 and 89 and Ocean Drilling Program Leg 160. Permeability tests on undisturbed whole-round samples from Napoli dome (Site 971) using a back-pressured system at effective stresses that ranged from 200 to 700 kPa revealed low hydraulic conductivities of the clay- rich, undisturbed “mud breccias,” which ranged from 5 × 10–8 to 5 × 10–9 mm/s. In general, conductivities of sediments from the footwall, flank, and crest of Napoli dome dropped to half their value when the load was incrementally increased from 500 up to 700 kPa. Pore volume, initially 50%−55%, was reduced to around 25% after multiple incremental loading between the permeability tests. Experiments on remolded mud breccia from Napoli dome (Site 971) and adjacent mud volcanoes using a geotechnical shear box as well as a Vane apparatus revealed peak shear strengths of 200−400 kPa. Plasticity indices also vary significantly for the mud-volcano deposits (i.e., from 25% to >40%), presumably because of variations in the composition and amount of the clay fraction. The friction angles obtained with shear tests indicate that montmorillonites (φ′ peak = 10°−15°) and fine grained carbonates (φ′ peak 27°−30°) are the two dominant mineral phases in the matrix.
    [Show full text]
  • The Effective Porosity and Grain Size Relations in Permeability Functions
    Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Hydrol. Earth Syst. Sci. Discuss., 11, 6675–6714, 2014 www.hydrol-earth-syst-sci-discuss.net/11/6675/2014/ doi:10.5194/hessd-11-6675-2014 © Author(s) 2014. CC Attribution 3.0 License. This discussion paper is/has been under review for the journal Hydrology and Earth System Sciences (HESS). Please refer to the corresponding final paper in HESS if available. The effective porosity and grain size relations in permeability functions K. Urumović1 and K. Urumović Sr.*, ** 1Croatian Geological Survey, Sachsova 2, P.O. Box 268, 10001 Zagreb, Croatia *formally at: University of Zagreb, Faculty of Mining, Geology and Petroleum Engineering, Zagreb, Croatia **retired Received: 5 April 2014 – Accepted: 21 May 2014 – Published: 24 June 2014 Correspondence to: K. Urumović ([email protected]) Published by Copernicus Publications on behalf of the European Geosciences Union. 6675 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Abstract Hydrogeological parameters of coherent and incoherent deposits are deeply dependent of their granulometric characteristics. These relations were shaped in formulas and defaultly used for calculation of hydraulic conductivity, and are valid only 5 for uniform incoherent materials, mostly sands. In this paper, the results of analyses of permeability and specific surface area as a function of granulometric composition of various sediments – from siltey clays to very well graded gravels are presented. The effective porosity and the referential grain size are presented as fundamental granulometric parameters which express an effect of forces operating fluid movement 10 through the saturated porous media. Suggested procedures for calculating referential grain size and determining effective (flow) porosity result with parameters that reliably determine specific surface area and permeability.
    [Show full text]
  • Correlation Between Laboratory and Field Permeability of Soils and Rocks
    ﺒﺴﻡ ﺍﷲ ﺍﻟﺭﺤﻤﻥ ﺍﻟﺭﺤﻴﻡ University of Khartoum Faculty of Engineering & Architecture Correlation between Laboratory and Field Permeability of Soils and Rocks A Thesis Submitted in Partial Fulfillment of the Requirements For the Degree of Master of Science in Structural Engineering By: Ahmed Abdallah Eltayeb Elfaki June 2006 DEDICATION • To my family • To all people whom works in a tough weather ACKNOWLEDGEMENTS The author wishes to express his great indebtness to the supervisor Dr. Hussien Arabi, Building and Road Research Institute (BRRI), University of Khartoum, for his kind help and guidance. Considerable thanks are due to the staff of (BRRI) for their great assistance. Thanks are extended to the laboratory staff for their help. In addition, I would like to express my appreciation to my family for supporting me. Ahmed ABSTRACT Permeability affects the performance of structure through the soil and rock pavements. Percolation of water, through the interconnected voids of soil and rock pavement, causes a number of soil and rock engineering problems such as settlement of buildings, yield of wells, seepage through and below the earth structures. In this study, laboratory and field permeability tests, based on the principles of falling head and lugeon test, were conducted on different borehole in Merowe irrigation project area and Khartoum New International Airport (KNIA), to study the correlation between the laboratory and the field permeability values. The main objective was to assess whether the field permeability values could be estimated from laboratory permeability values or any other parameter estimated from laboratory or field. The results show that there was a significant difference between the laboratory permeability measured and the field permeability values.
    [Show full text]
  • Predicting the Permeability of Sandy Soils From
    PREDICTING THE PERMEABILITY OF SANDY SOILS FROM GRAIN SIZE DISTRIBUTIONS A thesis submitted to Kent State University in partial fulfillment of the requirements for the Degree of Master of Science by Emine Mercan Onur May, 2014 Thesis written by Emine Mercan Onur B.S., Middle East Technical University, 2009 M.S., Kent State University, 2014 Approved by ___________________________________, Advisor ___________________________________, Chair, Department of Geology ___________________________________, Dean, College of Arts and Sciences ii TABLE OF CONTENTS LIST OF FIGURES ........................................................................................................... vi LIST OF TABLES ........................................................................................................... xiii ACKNOWLEDGEMENT ............................................................................................... xiv ABSTRACT ........................................................................................................................ 1 CHAPTER 1: INTRODUCTION ....................................................................................... 3 1.1 Background ............................................................................................................. 3 1.2 Factors affecting Permeability ................................................................................ 4 1.2.1 Effect of Grain Size and Grain Size Distribution ...................................................... 5 1.2.2 Effect of Density and
    [Show full text]
  • Chapter I Basic Characteristics of Soils Outline
    Chapter I Basic Characteristics of Soils Outline 1. The Nature of Soils (section 1.1 Craig) 2. Soil Texture (section 1.1 Craig) 3. Grain Size and Grain Size Distribution (section 1.2 Craig) 4. Particle Shape (part of section 1.4 Craig) 5. Atterberg Limits (section 1.3 Craig) 6. References 1. Soil Definitions • Civil Engineers define soils as any un-cemented accumulation of Mineral particles formed by the weathering of rocks, the voids spaces between the particles contain water and or air. weathering of rocks Physical weathering Sands, Gravel Chemical Weathering Clay 1.1 Origin of Clay Minerals “The contact of rocks and water produces clays, either at or near the surface of the earth” (from Velde, 1995). Rock +Water Clay For example, The CO2 gas can dissolve in water and form carbonic acid, which will become hydrogen ions H+ and bicarbonate ions, and make water slightly acidic. + - CO2+H2O H2CO3 H +HCO3 The acidic water will react with the rock surfaces and tend to dissolve the K ion and silica from the feldspar (common Mineral on earth crest). Finally, the feldspar is transformed into kaolinite. Feldspar + hydrogen ions+water clay (kaolinite) + cations, dissolved silica + + 2KAlSi3O8+2H +H2O Al2Si2O5(OH)4 + 2K +4SiO2 •Note that the hydrogen ion displaces the cations. 1.2 Basic Unit-Silica Tetrahedra (Si O )-4 1 Si 2 10 4 O Replace four Oxygen with hydroxyls or combine with positive union Tetrahedron Hexagonal Plural: Tetrahedra hole (Holtz and Kovacs, 1981) 1.3 Synthesis Mitchell, 1993 Noncrystall ine clay - allophane 1.4 1:1 Minerals-Kaolinite Basal spacing is 7.2 Å layer • Si4Al4O10(OH)8.
    [Show full text]
  • Plasticity, Strength and Permeability of Reclaimed Asphalt Pavement and Lateritic Soil Blends I.I
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Covenant University Repository International Journal of Scientific & Engineering Research, Volume 5, Issue 6, June-2014 631 ISSN 2229-5518 Plasticity, Strength and Permeability of Reclaimed Asphalt Pavement and Lateritic Soil Blends I.I. Akinwumi Abstract— This paper presents the results of laboratory evaluation of the effects of the addition of reclaimed asphalt pavement (RAP), to an A-2 lateritic soil, on the plasticity, strength and permeability of the soil. The natural soil was classified as A-2-6(1), according to AASHTO classification system. RAP was added to the soil in 0, 4, 8 and 12%, by dry weight of the soil. Specific gravity, Atterberg limits, compaction, California bearing ratio (CBR), unconfined compression and permeability tests were conducted on each of the soil-RAP blends. Results obtained show that as RAP content in the blend increased, the plasticity index, optimum moisture content, maximum dry unit weight, swell potential, unconfined compressive strength and permeability decreased while the specific gravity, soaked and unsoaked California bearing ratios increased. These results indicate that RAP effectively improved, especially, the plasticity and permeability of the soil. It also indicates that deformation should be a major design criterion while planning the use of lateritic soil-RAP blend as a road pavement layer material. Index Terms— laterite, recycled asphalt, soil modification, subgrade, sub-base, tropical soil, unbound granular materials —————————— —————————— 1 INTRODUCTION N today’s world, issues of reusing and recycling of non- virgin aggregates gave more satisfactory results than wholly I renewable resources as a means of minimizing waste and using RAP.
    [Show full text]