ajay berwal (1)

A PROJECT REPORTON

SOIL STABILIZATION USING GEOSYNTHETICS

Submitted by

MITESH RATHI

Under the Guidance of

Mr. AhzamShadabAssistant Professor

in partial fulfillment for the award of the degree of

BACHELOR OF TECHNOLOGYIN

CIVIL ENGINEERING

Faculty of Engineering & Technology

ManavRachna International University, Faridabad

JUNE, 2014

Acknowledgement

We would like to express our sincere gratitude toour project guide Mr. AhzamShadabfor giving us the opportunity to work on this topic. It would never be possible for us to take this project to this level without his innovative ideas and hisrelentless support and encouragement.

1. PrashantSheoran, 10/fet/c(f)/10352. Ankur Gill, 3. MiteshRathee(10/Fet/C(F)/1038)4. Ajay Berwal, 10/fet/c(f)/10365. Armaan,

Declaration

Weherebydeclarethat this project report entitled “Soil Stabilization Using Geosynthetics” by MITESH RATHI (10/Fet/C(F)/1038), being submitted in partial fulfillment of the requirements for the degreeof Bachelor of Technology in CIVIL ENGINEERINGunder Faculty of Engineering & Technology of ManavRachna International University Faridabad, during the academic year 2014, is a bonafide record of our original work carried out under guidance and supervisionof MR. AHZAM SHADAB, ASSISTANT PROFESSOR , CIVIL ENGINEERING DEPARTMENT and has not been presented elsewhere.

1. PrashantSheoran, 10/Fet/c(f)/10352. Ankur Gill, 3. MiteshRathi, (10/Fet/C(F)/1038)4. Ajay Berwal, 10/Fet/c(f)/10365. Armaan,

ManavRachnaInternational University, Faridabad

Faculty of Engineering & Technology

Department of Civil Engineering

June, 2014Certificate

This is to certify that this project report entitled “SOIL STABILIZATION USING GEOSYNTHETICS” by MITESH RATHI (10/FET/C(F)/1038)submitted in partial fulfillment of the requirements for the degreeof Bachelor of Technology in CIVIL ENGINEERING under Faculty of Engineering & Technology of ManavRachna International University Faridabad, during the academic year 2014, is a bonafide record of work carried out under my guidance and supervision.

Mr. AhzamShadabASSISTANT PROFESSOR Department. Of Civil EngineeringFaculty of Engineering & Technology ManavRachna International University, Faridabad

Dr. B.K. SinghProfessor and Head of the Department

CONTENT

Chapter PAGE NO

1. Introduction 1-2

1.1 Goals and Objectives 11.2 Details and Terminology 21.3 Organization of Project 2

2. Literature Review 3-8

2.1 Introduction to Geosynthetics 3

2.2 Theory of Compaction 7

3. Problem Statement 9

3.1 Requirements 9

3.2Commonoly used method for improvement of soil properties 9

4. Experiments and Results 10-25

4.1 Scope of work 10

4.2 Procedure for Experiments 10

4.3 Result of Performed Experiments 16

4.4 Comparative Statement 25

5. Conclusion 26

Bibliography 27

List of Figures

Fig 2.1 Differnet types of Geosynthetics 5

Fig 2.2 Soil Layer Separaton using Geosynthetics 6

Fig 2.3 Soil Reinforcement 6

Fig 2.4 Soil Filtration 7

Fig 2.5 Soil Drainage 7

Fig 4.1 Sieves of different Sizes 11

Fig 4.2 Casagrande Apparatus 12

Fig 4.3 Different Instruments Used in Proctor 13

Fig 4.4 Water Mixing in soil 13

Fig 4.5 Proctor Apparatus 14

Fig 4.6 Trimming of Soil 14

Fig 4.7 Pyncometer Apparatus 14

Fig 4.8 Triaxial Machine 16

Fig 4.9 Failure Due to load applied 16

LIST OF TABLES PAGE NO

Table 1.1 Sieve analysis 16

Table 4.2 Proctor test results for parent soil 17

Table 4.3 Proctor test result with 0.1% Geosynthetic 19




CHAPTER 1

INTRODUCTION

For any land-based structure, the foundation is very important and has to be strong to support the entire structure. In order for the foundation to be strong, the soil around it plays a very critical role. So, to work with soils, we need to have proper knowledge about their properties and factors which affect their behavior. The process of soil stabilization helps to achieve the required properties in a soil needed for the construction work.

From the beginning of construction work, the necessity of enhancing soil properties has come to the light. Ancient civilizations of the Chinese, Romans and Incas utilized various methods to improve soil strength etc., some of these methods were so effective that their buildings and roads still exist.

In India, the modern era of soil stabilization began in early 1970’s, with a general shortage of petroleum and aggregates, it became necessary for the engineers to look at means to improve soil other than replacing the poor soil at the building site. Soil stabilization was used but due to the use of obsolete methods and also due to the absence of proper technique, soil stabilization lost favor. In recent times, with the increase in the demand for infrastructure, raw materials and fuel, soil stabilization has started to take a new shape. With the availability of better research, materials and equipment, it is emerging as a popular and cost-effective method for soil improvement.

Here, in this project, soil stabilization has been done with the help geosynthetic fibers.

1.1 GOALS AND OBJECTIVES

The objective of the project was to analyze geotechnical fibres (i.e. asbestos fibre) with different proportions of water content, mixed with soil. The parameters that were to be brought out in the laboratory were MDD and OMC. This experimentation was to be carried out in relation to its use as a core filler material in construction of road embankments.The aim

of the entire activity striking economy in construction of roads and improving the soil properties by developing it as a construction material with functional geotechnical properties as a replacement of soil.

Acquisition of samples for the project was done from Palwal Haryana. The Standard Proctor tests were carried out simultaneously from the same batch to minimize variability due to difference in constituencies of lots. Water was added to the sample on weight/weight percentage basis by hit and trial method. Samples taken from each round of compaction were kept in oven at 105 degrees for 24 hours before taking the dry weight. Dry densities obtained from each sample were noted and a graph plotted with water content on the X axis and dry density on the Y axis. On joining the points obtained by a smooth line, MDD was obtained at a definite OMC, represented by the crest of the graph where the slope is zero. Asbestos Fibre was added to soil in different percentages to study if there is any considerable change in geotechnical properties. The graphs and observations obtained from these experiments are presented henceforth in this report.

1.2 DETAILS AND TERMINOLOGY

OMC – The maximum content at which a specified compactive force can compact a soil mass to its maximum dry unit weight.

COMPACTION – Compaction is a process that brings about an increase in soil density or unit weight, accompanied by a decrease in air volume. There is usually no change in water content. For a given compactive effort, the maximum dry unit weight occurs at optimum water content.

PAVEMENT – Road surface or pavement is the durable surface material laid down on an area intended to sustain traffic. Such surfaces are frequently marked to guide traffic.

MDD (Maximum Dry Density) – The dry density in g/cc corresponding to the maximum point on the moisture content /dry density curve should be reported as maximum dry density.

1.3 ORGANIZATION OF THE PROJECT

The objective of the project was to analyze geotechnical fibres (i.e. asbestos fibre) with different proportions of water content, mixed with soil. The parameters that were to be brought out in the laboratory were MDD and OMC. This experimentation was to be carried

out in relation to its use as a core filler material in construction of road embankments. The aim of the entire activity striking economy in construction of roads and improving the soil properties by developing it as a construction material with functional geotechnical properties as a replacement of soil.

Acquisition of samples for the project was done from Palwal Haryana. The Standard Proctor tests were carried out simultaneously from the same batch to minimize variability due to difference in constituencies of lots. Water was added to the sample on weight/weight percentage basis by hit and trial method. Samples taken from each round of compaction were kept in oven at 105 degrees for 24 hours before taking the dry weight. Dry densities obtained from each sample were noted and a graph plotted with water content on the X axis and dry density on the Y axis. On joining the points obtained by a smooth line, MDD was obtained at a definite OMC, represented by the crest of the graph where the slope is zero. Asbestos Fibre was added to soil in different percentages to study if there is any considerable change in geotechnical properties. The graphs and observations obtained from these experiments are presented henceforth in this report.

CHAPTER 2

LITERATURE REVIEW

Soil stabilization is the process of altering some soil properties by different methods, mechanical or chemical in order to produce an improved soil material which has all the desired engineering properties.

Soils are generally stabilized to increase their strength and durability or to prevent erosion and dust formation in soils. The main aim is the creation of a soil material or system that will hold under the design use conditions and for the designed life of the engineering project. The properties of soil vary a great deal at different places or in certain cases even at one place; the success of soil stabilization depends on soil testing. Various methods are employed to stabilize soil and the method should be verified in the lab with the soil material before applying it on the field.

Principles of Soil Stabilization:

• Evaluating the soil properties of the area under consideration.

• Deciding the property of soil which needs to be altered to get the design value and choose the effective and economical method for stabilization.

• Designing the Stabilized soil mix sample and testing it in the lab for intended stability and durability values.

2.1 INTRODUCTION TO GEOSYNTHETICS

Geosynthetics are the generally polymeric products used to solve civil engineering problems.

This includes eight main product

categories: geotextiles, geogrids, geonets,geomembranes, geosynthetic clay

liners, geofoam, geocells and geocomposites. The polymeric nature of the products makes

them suitable for use in the ground where high levels of durability are required. Properly

formulated, however, they can also be used in exposed applications. Geosynthetics are

available in a wide range of forms and materials, each to suit a slightly different end use.

These products have a wide range of applications and are currently used in many

civil, geotechnical, transportation, geoenvironmental,hydraulic, and

private development applications including roads, airfields, railroads, embankments, retaining

structures, reservoirs, canals, dams, erosion control, sediment control,landfill liners, landfill

covers, mining, aquaculture and agriculture.

Types of Geosynthetics

Geotextiles form one of the two largest groups of geosynthetics. Their rise in growth during the past 35 years has been nothing short of extraordinary. They are indeed textiles in the traditional sense, but they consist of synthetic fibers rather than natural ones such as cotton, wool, or silk. Thus bio degradation and subsequent short lifetime is not a problem. These synthetic fibers are made into flexible, porous fabrics by standard weaving machinery or are matted together in a random non woven manner. Some are also knitted. The major point is that geotextiles are porous to liquid flow across their manufactured plane and also within their thickness, but to a widely varying degree. There are at least 100 specific application areas for geotextiles that have been developed; however, the fabric always performs at least one of four discrete functions: separation, reinforcement, filtration, and/or drainage.

Geogrids represent a rapidly growing segment within geosynthetics. Rather than being a woven, nonwoven or knitted textile fabric, geogrids are polymers formed into a very open, gridlike configuration, i.e., they have large apertures between individual ribs in the transverse and longitudinal directions. Geogrids are (a) either stretched in one, two or three directions for improved physical properties, (b) made on weaving or knitting machinery by standard textile manufacturing methods, or (c) by laser or ultrasonically

bonding rods or straps together. There are many specific application areas, however, geogrids function almost exclusively as reinforcement materials.

Geonets, and the related geospacers by some, constitute another specialized segment within the geosynthetics area. They are formed by a continuous extrusion of parallel sets of polymeric ribs at acute angles to one another. When the ribs are opened, relatively large apertures are formed into a netlike configuration. Two types are most common, either biplanar or triplanar. Alternatively many very different types of drainage cores are available. They consist of nubbed, dimpled or cuspated polymer sheets, three-dimensional networks of stiff polymer fibers in different configurations and small drainage pipes or spacers within geotextiles. Their design function is completely within the drainage area where they are used to convey liquids or gases of all types

Geomembranes represent the other largest group of geosynthetics, and in dollar volume their sales are greater than that of geotextiles. Their growth in the United States and Germany was stimulated by governmental regulations originally enacted in the early 1980s for the lining of solid-waste landfills. The materials themselves are relatively thin, impervious sheets of polymeric material used primarily for linings and covers of liquids- or solid-storage facilities. This includes all types of landfills, surface impoundments, canals, and other containment facilities. Thus the primary function is always containment as a liquid or vapor barrier or both. The range of applications, however, is great, and in addition to the environmental area, applications are rapidly growing in geotechnical, transportation, hydraulic, and private development engineering (such as aquaculture, agriculture, heap leach mining, etc.).

Geosynthetic clay liners, or GCLs, are an interesting juxtaposition of polymeric materials and natural soils. They are rolls of factory fabricated thin layers of bentonite claysandwiched between two geotextiles or bonded to a geomembrane. Structural integrity of the subsequent composite is obtained by needle-punching, stitching or adhesive bonding. GCLs are used as a composite component beneath a geomembrane or by themselves in geoenvironmental and containment applications as well as in transportation, geotechnical, hydraulic, and many private development applications.

Geofoam is a product created by a polymeric expansion process of polystyrene resulting in a “foam” consisting of many closed, but gas-filled, cells. The skeletal nature of the cell walls is the unexpanded polymeric material. The resulting product is generally in the form of large, but extremely light, blocks which are stacked side-by-side providing lightweight fill in numerous applications.

Geocells (also known as Cellular Confinement Systems) are three-dimensional honeycombed cellular structures that form a confinement system when infilled with compacted soil. Extruded from polymeric materials into strips welded together ultrasonically in series, the strips are expanded to form the stiff (and typically textured and perforated) walls of a flexible 3D cellular mattress. Infilled with soil, a new composite entity is created from the cell-soil interactions. The cellular confinement reduces the lateral movement of soil particles, thereby maintaining compaction and forms a stiffened mattress that distributes loads over a wider area. Traditionally used in slope protection and earth retention applications, geocells made from advanced polymers are

being increasingly adopted for long-term road and rail load support. Much larger geocells are also made from stiff geotextiles sewn into similar, but larger, unit cells that are used for protection bunkers and walls.

A geocomposite consists of a combination of geotextiles, geogrids, geonets and/or geomembranes in a factory fabricated unit. Also, any one of these four materials can be combined with another synthetic material (e.g., deformed plastic sheets or steel cables) or even with soil. As examples, a geonet or geospacer with geotextiles on both surfaces and a GCL consisting of a geotextile/bentonite/geotextile sandwich are both geocomposites. This specific category brings out the best creative efforts of the engineer and manufacturer. The application areas are numerous and constantly growing. The major functions encompass the entire range of functions listed for geosynthetics discussed previously: separation, reinforcement, filtration, drainage, and containment.

Fig2.1 Different types of Geosynthetics

Advantages of using geosynthetics

Separation is the placement of a flexible geosynthetic material, like a porous geotextile, between dissimilar materials so that the integrity and functioning of both materials can remain intact or even be improved. Paved roads, unpaved roads, and railroad bases are common applications. Also, the use of thick nonwoven geotextiles for cushioning and protection of geomembranes is in this category. In addition, for most applications of geofoam and geocells, separation is the major function.

Fig2.2 Soil Layer Separation using Geosynthetics

Reinforcement is the synergistic improvement of a total system’s strength created by the introduction of a geotextile, geogrid or geocell (all of which are good in tension) into a soil (that is good in compression, but poor in tension) or other disjointed and separated material. Applications of this function are in mechanically stabilized and retained earth walls and steep soil slopes; they can be combined with masonry facings to create vertical retaining walls. Also involved is the application of basal reinforcement over soft soils and over deep foundations for embankments and heavy surface loadings. Stiff polymer geogrids and geocells do not have to be held in tension to provide soil reinforcement, unlike geotextiles. Stiff 2D geogrid and 3D geocells interlock with the aggregate particles and the reinforcement mechanism is one of confinement of the aggregate. The resulting mechanically stabilized aggregate layer exhibits improved loadbearing performance. Stiff polymer geogrids, with very open apertures, in addition to three-dimensional geocells made from various polymers are also increasingly specified in unpaved and paved roadways, load platforms and railway ballast, where the improved loadbearing characteristics significantly reduce the requirements for high quality, imported aggregate fills, thus reducing the carbon footprint of the construction.

Fig 2.3 Soil Renforcement

Filtration is the equilibrium soil-to-geotextile interaction that allows for adequate liquid flow without soil loss, across the plane of the geotextile over a service lifetime compatible with the application under consideration. Filtration applications are highway underdrain systems, retaining wall drainage, landfill leachate collection systems, as silt fences and curtains, and as flexible forms for bags, tubes and containers.

Fig2.4 Soil Filtration

Drainage is the equilibrium soil-to-geosynthetic system that allows for adequate liquid flow without soil loss, within the plane of the geosynthetic over a service lifetime compatible with the application under consideration. Geopipe highlights this function, and also geonets, geocomposites and very thick geotextiles. Drainage applications for these different geosynthetics are retaining walls, sport fields, dams, canals, reservoirs, and capillary breaks. Also to be noted is that sheet, edge and wick drains are geocomposites used for various soil and rock drainage situations.

Fig2.5 Soil Drainage

Containment involves geomembranes, geosynthetic clay liners, or some geocomposites which function as liquid or gas barriers. Landfill liners and covers make critical use of these geosynthetics. All hydraulic applications (tunnels, dams, canals, surface impoundments, and floating covers) use these geosynthetics as well.

2.2 THEORY OF COMPACTION

Compaction is the process of increasing the bulk density of a soil or aggregate by driving out air. For any soil, for a given amount of compactive effort, the density obtained depends on the moisture content. At very high moisture contents, the maximum dry density is achieved when the soil is compacted to nearly saturation, where (almost) all the air is driven out. At low moisture contents, the soil particles interfere with each other; addition of some moisture will allow greater bulk densities, with a peak density where this effect begins to be counteracted by the saturation of the soil. Compaction is used in construction of highway embankments, earth dams and many other engineering structures, loose soils must be compacted to improve their strength by increasing their unit weight. Degree of Compaction is measured in terms of Dry Unit Weight.

http://en.wikipedia.org/wiki/Bulk_density

There are five principle reasons to compact soil:

1. Increases load-bearing capacity

2. Prevents soil settlement and frost damage

3. Provides stability

4. Reduces water seepage, swelling and contraction

5. Reduces settling of soil

Objectives for Compaction

Increasing the bearing capacity of foundations Decreasing the undesirable settlement of structures Control undesirable volume changes Reduction in hydraulic conductivity Increasing the stability of slopes. Compaction Effects

In general, soil densification includes

Compaction

Consolidation

Compaction is one kind of densification that is realized by rearrangement of soil particles without outflow of water. It is realized by application of mechanical energy. It does not involve fluid flow but wish moisture changing altering.

Consolidation is another kind of soil densification with fluid flow. Consolidation is primarily for clayey soils. Water is squeezed out from pores under load.

There are four control factors affecting the extent of compaction:

1. Compaction effort;

2. Soil type and gradation;

3. Moisture content; and

4. Dry unit weight (dry density).

CHAPTER 3

PROBLEM STATEMENT

The purpose of the project is Stabilization of soil using geosynthetics. The project also aims at finding out the optimum mix proportion of geosyntheticfibre and soil so as to utilize the same for construction of embankments. The maximum benefit obtained from mixing geosyntheticfibres i.e. asbestos fibre can be used to increase the bearing capacity of soil. Whereas the basic problem statement is to mix asbestos fibre with soil at different proportions and compute various properties and results of compaction and strength.

3.1 REQUIREMENTS

To increase the bearing capacity of the soil.

To increase the consistency of the soil.

To increase the relative density of the soil.

3.2 COMMONLY USED METHODS FOR IMPROVEMENT OF SOIL

PROPERTIES:

PRE LOADING: Simply place a surcharge fill on top of the soil that requires improvement •Once sufficient consolidation has taken place, the fill can be removed and construction takes place.

SOIL REPLACEMENT: One of oldest and simplest methods is simply to remove and replace the soil.

SOIL STABLISATION: stabilization of soil is done using admixtures to enhance the soil quality most common admixture is Portland cement, lime and asphalt.

GROUTING: When low-slump compaction grout is injected into granular soils, grout bulbs are formed that displace and densify the surrounding loose soils.

In-place Densification of Soil:

(a) Vibroflotation : Probe includes the vibrator mechanism and water jets , probe is lowered into the ground using a crane .Vibratory eccentric force induces densification and water jets assist in insertion and extraction

(b) Compaction piles : in this method piles are inserted to compact the soil.

(c) Stone column : in this method water is jetted into the ground forming a large vertical hole. The hole is filled with gravel (stone) from the surface.

(d)Blasting: it uses deep densification of the soil can be accomplished by blasting.

CHAPTER 4

EXPERIMENTS AND RESULTS

4.1 SCOPE OF WORK

The experimental work consists of the following steps:

1. Specific gravity of soil

2. Determination of soil index properties (Atterberg Limits)

i) Liquid limit by Casagrande’s apparatus

ii) Plastic limit

3. Particle size distribution by sieve analysis

4. Determination of the maximum dry density (MDD) and the corresponding optimum moisture content (OMC) of the soil by Proctor compaction test

5. Preparation of reinforced soil samples.

6. Determination of the shear strength by:

ii) Unconfined compression test (UCS).

4.2 PROCEDURE FOR EXPERIMENTS

1. Sieve Analysis- It is carried out to obtain grain size of soil particles .The soil is sieved through a set of sieves. Sieves are generally made of spur brass and phosphor bronze (or stainless steel). The sieves are designed by the size of square openings in mm or microns. Sieves of various sizes ranging from 80mm to 75 microns are available .The dia. Of sieve is generally bet. 15 to 20 cm.

Procedure- The soil sample is taken in suitable quantity. The soil should be oven dried for 24 hrs at 110 degree.It should not contain any lumps. If necessary , it should be pulverised. The sample is sieved through 4.75mm IS sieve.The portion retained on the sieve is the gravel fraction material.It can be shake manually or machenical using a shaker. The weight of soil retained on each sieve is obtained. The sample is placed in the top sieve and the set of sieves is kept on a mechanical shaker and the machine I started. Normally 10 min.’s of shaking is enough for mostly soils.The mass of the retained on each and on pan is obtained to the nearest 0.1 gm. The mass of the retained soil is checked against the original mass.

Fig.4.1. Sieves of different sizes

2. Liquid Limit- The liquid limit is the water content at which the soil changes from the liquid state to the plastic state. At the liquid limit the clay is practically like a liquid, but possesses a small shearing strength. The shearing strength at the stage is the smallest value that can be measured in the laboratory. The liquid limit of soil depends upon the clay mineral present. The stronger the surface charge and the thinner the particle, the greater will be the amount of adsorbed water and, therefore , the higher will be the liquid limit. The liquid limit is determined in the laboratory either by Casagrande’s apparatus or by cone penetration method. The device used in Casagrande method consists of a brass cup which drops through a ht. of a 1 cm on a hard base when operated by the handle. The device is operated by turning the handle which raises the cup and lets it drop on the rubber base. The ht. of drop is adjusted with the help of adjusting screws.

Procedure- About 120 gm. of an air dried soil sample passing through 4-5 micron sieve is taken in a dish and mixed with distilled water to form a uniform paste. A portion of this paste is placed in the cup of the liquid limit device, and the surface is smoothened and a levelled with a spatula to a maximum depth of 1 cm. A groove is cut through the sample along the symmetrical axis of the cup, preferably in one stroke, using a standard grooving tool. IS 2720 part B recommends two types of grooving tool: (1) Casagrandetool , (2) ASTM tool. The CAsagrande tool cut a groove of width 2mm at the bottom, 11mm at the top and 8mm deep. The ASTM tool cuts a groove of width 2mm at the bottom, 13.6 mm at the top and 10mm deep the Casagrande tool is recommended for normal fine grained soils, whereas the ASTM tool is recommended for sandy, fine grained soils, in which the Casagrande tool tends to tear the soil in the groove.

After the soil pat has been cut by a proper grooving tool, the handle is turned at a rate of 2 revolutions per second until the two parts of the sample come into the contact at the bottom of the groove along a distance of 12mm. The groove should close by a flow of the soil and not by slippage between the soil and the cup when the groove closes by a flow, it indicates the failure of the slopes formed on the two sides of the groove.

Fig. 4.2 Casagrande Apparatus

3.Plastic Limit- Plastic limit is the water content below which the soil stops behaving as a plastic material. It begins to crumble which rolled into a thread of soil of 3 mm dia. . At this water content , the soil loses its plasticity and passes to a semi solid state.

Procedure- For determination of the plastic limit of a soil , it is air dried and sieved through a 4-5 micron IS sieve. About 30 gm. Of soil is taken in an evaporating dish. It is mixed thoroughly with distilled water till it becomes plastic and can be easily moulded with fingers. About 10gm. Of the plastic soil mass is taken in one hand and a ball is formed. The ball is rolled with fingers on a glass plate to form a soil thread of uniform dia. The rate of rolling is kept about 80 to 90 strokes per minute. IF the dia. Of thread becomes smaller than 3 mm , without crack formation it shows that the water content is more than the plastic limit. The soil is knead further. This results in the reduction of the water content as some water is evaporated due to the heat of the hand the soil is rerolled and the procedure repeated till the thread crumbles the water content at which the soil can be rolled into a thread of approximately 3 mm in dia. Without crumbling is known as the plastic limit (PL or wp). The test is repeated, taking a fresh sample each time . The plastic limit is taken as the average of 3 values. The plastic limit is reported to the nearest whole no. The shear strength at the plastic limit, is about 100 times that at the liquid limit.

4. Standard proctor test- To assess the amount of compaction and the water content required in the field , the compaction test are done on the same soil in the laboratory. The tests provide a relationship bet. the water content and the dry density. The water content at which the maximum dry density is attained is obtained from the relationship provided by the test Proctor (19930 used a standard mould of 4 inches internal dia. And an effective ht. of 4.6 inches , with a capacity of 1/30 cubic foot. The mould had a detachable base plate , and removable collar of 2 inches ht. at its top. The soil was compacted in the mould in three equal layers, each layer was given 25 blows of 5.5 pounds rammer falling through a ht. of 12 inches. A curve was obtained bet. The dry density and the water content.

IS : 2720 (Part 7 ) recommends essentially the same specification as a Standard Proctor test, with some minor modification and metrification. The mould recommended is of 100mm dia., 127.3 mm ht. and 1000 ml capacity. The rammer recommended is of 2.6 kg mass with a free drop of 310mm and a face dia. Of 50 mm. The soil is compacted in 3 layers. The mould is fixed to a detachable base plate. The collar is of 60 mm ht..

If the percentage of soil retained on 4.75 mm sieve is more than 20 % , a larger mould of internal dia. 150 mm , effective ht. 127.3 mm and capacity 2250 ml is recommended.

Procedure- About 3 kg of air dried pulverised soil passing 4.7 mm sieve is taken. Water is added to the soil to bring its water content to about 4 % if the soil is coarse grained and to about 8 5 if it is fine grained. The content should be much less than the expected optimum water content. The soil is mixed thoroughly and covered with a wet cloth and left for maturing for about 15-30 mins..The mould is cleaned dried and greased lightly. The mass of the empty mould with the base plate, but without collar , is taken. The collar is then fitted to the mould. The mould is placed on a solid base and filled with fully matured soil to about 1/3 its ht. The soil is compacted by 25 blows of the rammer , with a free fall of 310 mm . ( The no. of blows required for the bigger mould of 2250ml capacity is 56 instead of 25). The blows are evenly distributed over the surface the soil surface is scratched with a spatula before the second layer is placed. The mould is filled to about 2/3 ht. with the soil and compact again by 25 blows. Likewise, the third layer is placed and compacted. The third layer should project about the top of the mould into the collar by not more than 6mm. The collar is rotated to break to the bond bet. The soil in the mould and that in collar. The collar is than removed , and the soil trimmed of flush with the top of the mould. The mass of the mould, base plate and the compacted soil is taken and thus the mass of the compacted soil is determined. The bulk density of the soil is computed from the mass of the compacted soil and the volume of the mould. Representative soil samples are taken from the bottom, middle and top of the mould determining the water content. The dry density is computed from the bulk density and the water content.The soil removed from the mould is broken with hand. More water is added to the soil so as to increase the water content by 2-3%. It is thoroughly mixed and allowed to mature. The test is repeated and the dry density and the water content are determined.

Fig.4.3Different Instruments used in ProctorFig. 4.4 Water Mixing in soil

Fig. 4.5 Proctor Apparatus Fig.4.6Trimming of soil

5. Pycnometer- It is use to determine specific Gravity. It is a glass jar of 1 litre capacity and fitted with a screw type brass conical cap the cap has a small hole of 6 mm dia. A rubber or fibre washer is placed between the cap and also on jar. The cap is screwed down to the same mark such that the volume of the pyncometer used in calculation remains constant.

Procedure- A sample of 200-400gm is taken in the pyncometer and weighted. Water is then added to the soil in the pyncometer to make it about half full. The contents are thoroughly mixed using a glass rod to remove the entrapped air. More and more water is added and stirring process continued till the pyncometer is filled flush with the hole in the conical cap. The pyncometer is wiped dry and weighed. The pyncometer is then completely emptied. It is washed thoroughly and filled with water, flush with the top hole. The pyncometer is wiped dry and weighed.

Fig.4.7Pyncometer Apparatus

M1= mass of pycnometer

M2= mass of pycnometer + wet soil

M3 = mass of pycnometer + wet soil + weight of water

M4= mass of pycnometer filled with water only

Specific Gravity (G) = M2-M1/(M2-M1)-(M3-M4)

6. Triaxial Compression test Apparatus-

The triaxial compression test, or simply triaxial test, is used for the determination of shear characteristics of all types of soils under different drainage conditions. In this test , a cylindrical specimen is stressed under condition of axial symmetry. In the first stage of the test, the specimen is subjected to an all round confining pressure on the sides and at the top and the bottom. This stage is known as the consolidation stage.

In the second stage of the test, call the shearing stage and additional axial stress known as the Deviator stress, is applied on the top of the specimen through a ram. Thus, the total stess in the axial direction at the time of shearing is equal to (sigma c + sigma d). It may be noted that when the axial stress is increased the shear stresses develop on inclined planes due to compressive on the top.

The vertical sides of the specimen are principal planes as there are no shear stresses on the sides. The confining pressure is equal to the minor principal strss. The top of the bottom planes are the major principal planes. The total axial stress which is equal to the sum of confining pressure and deviator, is the major principal stress. Because of the axial symmetry, the intermediate principal stress is also equal to the confining pressure.

It consist of a circular base that has a pedestal. The pedestal has one or two holes which are used for the drainage of the specimen in the drained test or fpr the pour pressure measurement in an undrained test. A triaxial cell is fitted to the top of the base plate with the three wing nuts after the specimen has been placed on the pedestal. The triaxial cell is a Perspex cylinder which is permanently fixed to the top cap and the bottom brass collar. There are three tie rods which support to the cell. The top cap is a bronze casting with its central boss forming a bush through which a stainless steel ram can slide. The ram is so designed that it has minimum of friction at the same time does not permit any leakage. There is an air release valve in the top cap which is kept upon when the cell is filled with water ( orglycerine) for applying the confining pressure. An oil valve is also provided in the top cap to fill light machine oil in the cell to reduce the leakage of water past the ram in long duration tests. The apparatus is mounted on a loading frame. The deviator stress is applied to the specimen from a strain controlled loading machine. The loading system consist of either a screw jack operated by an electric motor and gear box or a hydraulic ram operated by a pump.

4.8 Triaxial Machine 4.9 Failure due to Load applied

4.3 RESULTS OF PERFORMED EXPERIMENTS

1. Sieve Analysis Test Results for Parent Soil

Wt. of soil sample=966gms

IS SEIVE NO.

MASS RETAINED (gms)

CUMM. RETAINED ED (Gms.)

CUMM.% RETAINED

TOTAL PASSING %age

4.75mm 0 0 0 0

2.36 mm 212 21.94 21.94 78.06

1.18 mm 104 10.76 32.70 67.30

600 micron

254 24.22 56.92 43.08

300 microne

54 5.59 62.51 37.49

150 microne

86 8.9 71.40 28.60

75 microne

126 13.04 84.44 15.56

Pan 150 15.11 99.55 0.45

Total 966 529.42

Table 4.1 Sieve Analysis

Fines Modulus= sum of cumulative percentage weight Retained/100=529.42/100=5.29.

2.0Pycnometer Test Results for Parent Soil

A sample of 200-400gm is taken in the pyncometer and weighted. Water is then added to the soil in the pyncometer to make it about half full. The contents are thoroughly mixed using a glass rod to remove the entrapped air. More and more water is added and stirring process continued till the pyncometer is filled flush with the hole in the conical cap. The pyncometer is wiped dry and weighed. The pyncometer is then completely emptied. It is washed thoroughly and filled with water, flush with the top hole. The pyncometer is wiped dry and weighed.

M1= mass of pycnometer

M2= mass of pycnometer + wet soil

M3 = mass of pycnometer + wet soil + weight of water

M4= mass of pycnometer filled with water only

M1=.469kg

M2=.669kg

M3=1.160

M4=.989

Specific Gravity (G) = M2-M1/(M2-M1)-(M3-M4)

= 6.89

3.0 Proctor Test

For Parent Soil Results are-

Table 4.2 Proctor Test Results for Parent soil

0 2 4 6 8 10 12 14 160

0.5

1

1.5

2

2.5

Parent Soil

Water Content%

Max

imum

Dry

Den

sity

(kg/

m3)

Graph 4.1-On parent soil

Container no.

%age of water

Wt. of Mould

W1 in kg

W2 in kg

Dry Density kg/m3

Moisture Content

M.D.D

In kg /m3

Wt. of soil required for Test(in Gms)

Water Required For Test(in ml.)

OMC

Triaxial Apparatus

(strength Kpa)

14 5 3.825

.045

.043

1737.60

.0444(4.4)

1664.36(1.664)

121.90

5.364 23.816

238

10 10 4.026

0.043

.041

1941.39

.044(4

.4)1858.83(1.858)

136.09

5.98 26.58

252

4 15 4.106

0.057

.054

2073.88

.052(5

.2)1970.9(1.9709)

144.36

7.509 39.03

243

0 0.5 1 1.5 2 2.5 3 3.50

50

100

150

200

250

300

Parent Soil

Strength (Kpa)

Deformation (mm)

Stre

ngth

(kpa

)

Graph 4.2- Strength Parameters on Parent Soil

After adding .01% (3gm) geosynthetics `the results are:

Container no.

%age of water

Wt. of Mould

W1

W2

Density (kg/m3)

Moisture Content in %

M.D.D Wt. of soil required for Test(in Gms)

Water Required for Test (in ml.)

OMC

Triaxial Apparatus

(Strength Kpa)

4

5%

4.033

0.025

.023

1946.3

8.6(.086)

1792.17(1.792)

131.26

11.28 97.07

270

2 10% 4.134

0.031

.029

2047.78

6.8(.068)

1917.3(1.917)

140.44

12.07 82.13

282

12 15% 4.121

0.036

.032

2034.73

12.5(.0125

1808.6(1.8080

132.46

16.55 206.9

277

16 20% 4.080

.029

.027

1987.55

7.4(.074)

1850.55(1.850)

135.54

10.03 74.22

265

Table4.3- Proctor Test Result with 0.1% Geosynthetic

Graph 4.3- Corresponding to 0.1% of Geosynthetic

0 0.5 1 1.5 2 2.5 3 3.50

50

100

150

200

250

300

Strength Parameters after adding 0.1% geosynthetics

Strength (Kpa)

Deformation (mm)

Stre

ngth

(kpa

)

Graph 4.4- Strength Parameters after adding 0.1% of Geosynthetic

After adding 0.2% Geosynthetic the results are:

Table 4.4- Proctor Test Results with 0.2% Geosynthetic


Container no.

%age of water

Wt. of Mould

W1 W2

Dry Density

Moisture Content



OMC

Triaxial Apparatus

(strength Kpa)

115 5 3.823

0.043

.041

1735.59

4.6 1659.17(1.659)

121.52

5.59 25.17

295

24 10 4.034

0.042

.040

1947.4

4.7 1859.9(1.859)

136.17

6.40 30.08

310

35 15 4.137

0.039

.037

2050.79

5.12 1950.9(1.950)

142.83

7.31 37.44

304

1 20 4.078

.054

.051

1992.5

5.5 1888.6(1.8880)

138.14

7.59 41.77

287

0 0.5 1 1.5 2 2.5 3 3.5 4 4.50

50100150200250300350400450500


Strength (Kpa)

Deformation (mm)

Stre

ngth

(kpa

)


After adding .04% (12gm) of Geosynthetic results are :

Container no.

%age of water

Wt. of Mould

W1 W2 Density Moisture Content



O.M.C

Triaxial Apparatus

(strength Kpa)

2 6 4.051

.032

0.030

1946.46

6.2 1849.7(1.849)

135.4 8.3 52.06 400

1 10 4.290

.024

0.022

4.016 8.3 2035.4(2.035)

149.06 12.37 102.69

418

12 14 4.147

.044

0.042

3.968 4.54 1972.08(1.972)

144.44 6.48 29.412

406

10 18 4.132

.034

o.032

3.905 5.8 1933.6(1.933)

141.59 8.21 47.63 384

Table 4.5.- Proctor Test Result with 0.4% Geosynthetic

Graph 4.7 Corresponding to 0.4% of Geosynthetic

0 0.5 1 1.5 2 2.5 3 3.5 4 4.50

50100150200250300350400450500


Strength (Kpa)

Deformation (mm)

Stre

ngth

(kpa

)


After Adding .06% geosynthetic results are:

Container no.

%age of water

Wt. of Mould

W1 W2 Density

Moisture Content



O.M.C

Triaxial Apparatus

(strength kpa)

16 5 3.890 0.026

.024 1796.82

7.69 1668.51(1.668)

122.181 9.35 71.40 450

3 10 4.094 .026

.024 2007.62

7.69 1864.2(1.864)

136.53 10.5 274.34

470

4 15 4.051 0.027

0.023

1964 14.8 1710.8(1.710)

125.25 18.5 79.79 455

2 20 3.975 0.044

.036 1864.08

18.18 1579.7(1.579)

115.71 20.8 378.40

442

Table 4.6- Proctor Test Results with 0.6% Geosynthetic

Graph 4.9 – Corresponding to 0.6% of Geosynthetic

0 0.5 1 1.5 2 2.5 3 3.5 4 4.50

50100150200250300350400450500


Strength (Kpa)

Deformation (mm)

Stre

ngth

(kpa

)


4.4 Comparative statement. 5% 10% 15% 20%Maximum Dry Density(parent soil) 1.6643 1.8583 1.9709 failsMDD usinggeosynthetic (0.01%) 1.7920 1.9173 1.808 1.850MDD usinggeosynthetic (0.02%) 1.659 1.859 1.950 1.888MDD usinggeosynthetic(0.04%) 1.8492.035 1.972 1.933MDD usinggeosynthetic(0.06%) 1.668 1.7108 1.864 1.579

5% 10% 15% 20%Optimum moisture cont. (parent soil) 23.816 26.58 39.04 fails OMC of geosynthetic (0.01%) 97.07 82.13 206.9 74.2 OMC of geosynthetic (0.02%) 25.71 30.08 37.44 41.70 OMC of geosynthetic(0.04%) 52.06 102.6 29.419 47.84 OMC of geosynthetic(0.06%) 71.4 274.3 79.79 378.49

CHAPTER 5

CONCLUSION

On the basis of present experimental study, the following conclusions are drawn:

1.THE Value of cohesion increases due to inclusion of fibre. The variation of cohesion with percentage of fiber content is observed to be non linear.the value obtained for cohesion indicates that soil obtained is of very stiff nature.

2.THE Shear strength of the soil is improved due to the addition of the fibre.upto some extent shear strength increases considerably and later Small reduction is observed.

3. THE ADDITION Of fibre results in reducing the consolidation settlement of clayey soil .it had an insignificant effect on the soil characteristics.

4.fibre significantly reduced the extent and distribution of cracks due to desiccation .it improves the strength behavior of unsaturated clayey soils and can potentially reduce ground improvement costs by adopting this method.

5.the most important point is the environmental concern regarding the effects of waste material in soil and the problems and threats that is related to their excessive usuage and disposal.this gives an effective solution to waste treatment of soil.

6. Overall it can be concluded that fiber reinforced soil can be considered to be good ground improvement technique specially in engineering projects on weak soils where it can act as a substitute to deep/raft foundations, reducing the cost as well as energy.

Based on direct shear test on soil sample- 1, with fiber reinforcement of 0.01%, 0.2%,0.4% and 0.6%, the increase in strength was found to beput the values .

BIBLIOGRAPHY

SOIL MECHANICS AND FOUNDATION ENGINEERING : DR KR ARORA

Soil mechanics and foundations: Dr.bcpunimia, akjain

Soil testing for engineers: S MITTAL

International geosynthetic s society website

Geosynthetica.net

Geosynthetics from Wikipedia

ajay berwal (1)

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