labratory report on soil plasticity,compactmen

Laboratory 1 : Soil Plasticity Test Liquid limit and plastic limit test

IntroductionThe liquid limit (LL) is conceptually defined as the water content at which the behaviour of a clayey soil changes fromplastictoliquid. However, the transition from plastic to liquid behaviour is gradual over a range of water contents, and the shear strength of the soil is not actually zero at the liquid limit. The plastic limit (PL) is determined by rolling out a thread of the fine portion of a soil on a flat, non-porous surface. The procedure is defined in ASTM Standard D4318. If the soil is at a moisture content where its behaviour is plastic, this thread will retain its shape down to a very narrow diameter. The sample can then be remoulded and the test repeated. As the moisture content falls due to evaporation, the thread will begin to break apart at larger diameters. The plastic limit is defined as the moisture content where the thread breaks apart at a diameter of 3.2 mm. A soil is considered non-plastic if a thread cannot be rolled out down to 3.2 mm at any moisture.

Apparatus and procedureApparatus Porcelain evaporating dishes or similar mixing dishes Pulverizing apparatus - mortar and rubber-covered pestle. U.S. No. 40 (0.425 mm) sieve. Spatula, about 75 mm long and approximately 19 mm wide. Balance sensitive to 0.01 g. Watering bottle, with distilled, demineralized or tap water. Grooving tool and gauge Drying oven Desiccator

Procedure liquid limit test

1. 3/4 of the soil that is 300 grams was roughly chosen and placed it into the porcelain dish. Assumed that the soil was previously passed through a No. 40 sieve, air-dried, and then pulverized.2. The soil was thoroughly mixed with a small amount of distilled water until it appears as a smooth uniform paste. Covered the dish with cellophane to prevent moisture from escaping.3. Weighed four of the empty moisture cans with their lids, and record the respective weights and can numbers on the data sheet.4. The liquid limit apparatus was adjusted by checking the height of drop of the cup. The point on the cup that comes in contact with the base should rise to a height of 10 mm. The block on the end of the grooving tool is 10 mm high and should be used as a gage. 5. Practiced using the cup and determined the correct rate to rotate the crank so that the cup drops approximately two times per second.6. Placed a portion of the previously mixed soil into the cup of the liquid limit apparatus at the point where the cup rests on the base. Squeezed the soil down to eliminate air pockets and spread it into the cup to a depth of about 10 mm at its deepest point. The soil pat should form an approximately horizontal surface.7. The grooving tool used carefully to cut a clean straight groove down the centre of the cup. The tool should remain perpendicular to the surface of the cup as groove is being made. Use extreme care to prevent sliding the soil relative to the surface of the cup.8. Determined that the base of the apparatus below the cup and the underside of the cup is clean of soil. 9. The crank of the apparatus at a rate of approximately turned two drops per second and counted the number of drops, it takes to make the two halves of the soil pat come into contact at the bottom of the groove along a distance of 13 mm. 10. A sample was taken using the spatula, from edge to edge of the soil pat. The sample included the soil on both sides of where the groove came into contact. 11. Placed the soil into a moisture can and covered it. Immediately weighed the moisture can containing the soil, recorded its mass, removed the lid, and placed the can into the oven. 12. Leaved the moisture can in the oven for at least 24 hours. Placed the soil remaining in the cup into the porcelain dish. The cup on the apparatus and the grooving tool was cleaned and dried. 13. Mixed the entire soil specimen in the porcelain dish. Added a small amount of distilled water to increase the water content so that the number of drops required to closed the groove decrease.14. Steps six, seven, and eight repeated for at least two additional trials producing successively lower numbers of drops to close the groove.

Procedure for plastic limit test

1. The remaining empty moisture cans was weighed with their lids, and recorded the respective weights and can numbers on the data sheet.2. A sample of about 20g is taken from the soil paste prepared and placed on the glass plate.3. Added distilled water until the soil is at a consistency where it can be rolled without sticking to the hands.4. The soil formed into an ellipsoidal mass. The mass rolled between the palm and the glass plate. Sufficient pressure used to roll the mass into a thread of uniform diameter. 5. Once the diameter of the thread reaches the correct diameter, the thread was broke into several pieces. The pieces reformed and kneaded into ellipsoidal masses and re-rolled. The process continued. 6. The portions of the crumbled thread gathered together and the soil placed into a moisture can then covered. Moisture contained soil weighed and the mass was recorded. The lid removed and placed into the oven. The moisture leaved in the oven for 24 hours.7. Same step repeated few times. The water contained from each trial was determined by using same method in the laboratory.

Readings and calculations

TestM1gramsM2gramsM3gramsPenetrationMoisture content/ %

1172521.074100.00

2172823.019469.23

3172925.531141.20

4173330.037923.08

M1=mass of empty containerM2= Mass of container + wet soil M3 = Mass of container + dry soil

= =

Plastic Limit

Comparison and discussion of resultsThe importance of the liquid limit test is to classify soils. Different soils have varying liquid limits. Also to find the plasticity index of a soil you need to know the liquid limit and the plastic limit. The values of these limits are used in a number of ways. There is also a close relationship between the limits and properties of a soil such as compressibility, permeability, and strength. This is thought to be very useful because as limit determination is relatively simple, it is more difficult to determine these other properties. Different types of clays have different specific surface areas which controls how much wetting is required to move a soil from one phase to another such as across the liquid limit or the plastic limit. From this activity, it can predict the dominant clay type present in a soil sample. High activity signifies large volume change when wetted and large shrinkage when dried. Soils with high activity are very reactive chemically. Normally the activity of clay is between 0.75 and 1.25, and in this range clay is called normal. It is assumed that the plasticity index is approximately equal to the clay fraction (A = 1). When A is less than 0.75, it is considered inactive. When it is greater than 1.25, it is considered active.

ConclusionsThe conclusion is, another method for measuring the liquid limit is the fall cone test. It is based on the measurement of penetration into the soil of a standardized cone of specific mass. The importance of the liquid limit test is to classify soils. Different soils have varying liquid limits. Also to find the plasticity index of a soil need to know the liquid limit and the plastic limit.

Laboratory 2 : Soil Compaction Test Standard Proctor Test

IntroductionSoil compaction occurs when soil particles are pressed together, reducing pore space between them. Heavily compacted soils contain few large pores and have a reduced rate of both water infiltration and drainage from the compacted layer. This occurs because large pores are the most effective in moving water through the soil when it is saturated. Finally, while soil compaction increases soil strength-the ability of soil to resist being moved by an applied force-a compacted soil also means that roots must exert greater force to penetrate the compacted layer. TheProctor compaction testis a laboratory method of experimentally determining the optimalmoisture contentat which a givensoiltype will become most dense and achieve its maximum drydensity. The term Proctor is in honour ofR. R. Proctor, who in 1933 showed that the dry density of a soil for a given compactive effort depends on the amount of water the soil contains duringsoil compaction. Apparatus and procedureApparatus Compaction mold No. 4 U.S sieve Standard Proctor hammer Balance sensitive up to 0.01 gram Balance sensitive up to o.1 gram Large flat pan Jack Steel straight edge Moisture cans Drying oven Bottle with water

Procedure

1. 10 lb of air dried soil obtained and the soil lumps was broke.2. The soil sieved on a No.4 U.S sieve.3. All the minus 4 sieve materials about 6 lb was collected in a large pan.4. Water added to the minus 4 sieved materials and mixed thoroughly to bring moisture content to about 5%.5. Proctor mould and base plate weight was determined. The extension to the top of the mould attached.6. Moist soil poured into three layers. Each layers compacted uniformly with the Standard Proctor hammer 25 times for each additional layer of loose soil is poured.7. At the end of the each layer compaction, the soil extended slightly above the top of the rim of the compaction mould.8. The extension removed carefully and excess soil trimmed with a straight edge. 9. The weight of the Proctor Mould, base plat and compacted moist soil weighed.10. Base plate removed from the mould. The compacted moist soil extruded using a jack.11. A moisture can were weighed. From the moist soil extruded in previous step, a moist sample collected in the weighed moisture can. Weight of moisture can and soil determined together.12. Moisture can with soil in the oven placed to dry to a constant weight.13. The rest of the soil cylinder broke by hand and mixed with the left over moist soil. More water added mixed to raise moisture content by 2%.14. Step 6 to 11 repeated. The weight of the mould, base plate and moist soil first increased with the increase in moisture content and then decreased. The test continued until at least two successive decreased readings are obtained.15. After 24 hours, the mass of the moisture can and soil sample determined together.

Readings and calculations

Test 123

(g)1074.61074.61074.6

(g)3062.43423.43920.7

(g)30.030.030.0

(g)45.246.346.2

(g)37.238.139.2

Water content ,w (%)1.111.010.76

0.3740.4430.537

Comparison and discussion of resultsFrom the graph, we know that the Optimum unit dry weight is 0.533 and the Optimum water content is 0.766. This laboratory tests generally consist of compacting soil at known moisture content into a cylindrical mould of standard dimensions using a comp active effort of controlled magnitude. The soil is usually compacted into the mould to a certain amount of equal layers, each receiving a number blows from a standard weighted hammer at a specified height. This process is then repeated for various moisture contents and the dry densities are determined for each. The graphical relationship of the dry density to moisture content is then plotted to establish the compaction curve. The maximum dry density is finally obtained from the peak point of the compaction curve and its corresponding moisture content, also known as the optimal moisture content.

ConclusionCompaction is the process by which the bulk density of an aggregate of matter is increased by driving out air. For any soil, for a given amount of comp active 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. Generally there are 13 steps on doing compaction based on Malaysias methods and technologies. These steps must be carried out professionally according to the highest specifications and international standards that available without compromise. Developers, consultants, local authorities and the contractor must aware the bad consequences that probably happen if neglecting any aspect in the process and should be responsible to the scope of works that delegated to them by the users.

Laboratory 3 : Permeability and Seepage Constant Head Test & Seepage Physical Model

IntroductionPermeability is a measure of the ease in which water can flow through a soil volume. It isone of the most important geotechnical parameters. However, it is probably the mostdifficult parameter to determine. The constant head permeability test involves flow of water through a column of cylindrical soil sample under the constant pressure difference. The soil sample has a cylindrical form with its diameter being large enough in order to be representative of the tested soil. The usual size of the cell often used for testing common sands is 75 mm diameter and 260 mm height between perforated plates. The testing apparatus is equipped with an adjustable constant head reservoir and an outlet reservoir which allows maintaining a constant head during the test.

Apparatus and procedure

Apparatus Permeameter Tamper Balance Scoop 1000 ml graduated cylinders Stopwatch Thermometer Filter paper

Procedure

1. Initial mass of the pan along with the dry soil measured.2. The cap and upper chamber of the permeameter removed by unscrewing the knurled cap nuts and lifted them off the tie rods.3. The inside diameter of upper and lower chambers are measured. The average inside diameter of the permeameter calculated.4. One porous stone on the inner support ring in the base of the chamber placed then a filter paper placed on the top of the porous stone.5. The soil mixed with a sufficient quantity of distilled water to prevent the segregation of particle sizes during placement into the permeameter. Enough water should be added so that the mixture may flow freely.6. A scoop used to pour the prepared soil into the lower chamber using a circular motion to fill it to a depth of 1.5cm. A uniform layer formed.7. The tamping device used to compact the layer of soil. Approximately ten rams of per layer tamped and uniform coverage of the soil surface provided. The compaction procedure repeated until the soil is within 2cm of the top of the lower chamber section.8. The upper chamber section released. The placement operation continued until the level of the soil is about 2cm. The top surface of the soil levelled and a filter paper placed then upper porous stone keep on it.9. The compression spring placed on the porous stone and the chamber cap and its sealing gasket replaced. The cap firmly secured with the cap nuts.10. The sample length at four locations measured around the circumference of the permeameter and the average length computed. 11. The pan with remaining soil kept in the drying oven.12. Funnel level adjusted to allow the constant water level in it to remain a few inches above the top of the soil.13. Flexible tube connected from the tail of the funnel to the bottom outlet of the permeameter and the valves on the top of the permeameter kept opened.14. Tubing placed from the top outlet to the sink to collect any water that come out.15. Bottom valve opened and the water allowed to flow into the permeameter.16. Once the water start to flow out of the top control valve, then the control valve closed. Water flow let out of the outlet for some time.17. The bottom outlet valve closed and disconnected from the tubing at the bottom. Then funnel tubing connected to the tubing from the top side port.18. The bottom outlet valve opened and raised the funnel to a convenient height to get a reasonable steady flow of water.19. Adequate allowed time for the flow pattern to stabilize.20. The time it takes to fill a volume of 750ml 1000ml measured using the graduated cylinder and measured the temperature of the water. This process repeated three times and the average time, average volume, and average temperature computed.21. The vertical distance between the funnel head level and the chamber outflow level measured and levelled. The distance recorded as h.22. Step 18 and 19 repeated with different vertical distances.23. The pan removed from drying oven and the final mass of the pan measured along with the dry soil.

Calculations and readings

Initial dry mass of soil + pan = 1675.0g Length of soil specimen, L = 17 cmDiameter of the soil specimen, D = 6.4 cmFinal dry mass soil + Pan = 865.6gDry mass soil specimen = 809. 4gVolume of the soil specimen = 846.9 cm3Dry density of soil = 1.48g/cm3

Trial numberConstant head,h (cm)Elapsed time,t(s)Outflow volume,Q(cm3)Water temp,TKt(cm/sec)

K20(cm/sec)

13084750220.1570.149

25055750220.1440.137

36048750220.1370.130

47038750220.1490.142

Comparisons and discussionsThe K value is 0.149 g/cm.s. The system proposed in this study is a constant head permeameter. The measuring procedure of the method is almost same with the laboratory constant-head test except the driving force to flow water through column filled with porous materials. Water flow through the column in laboratory constant head test is driven by gravity, while in the proposed permeameter by the induced hydraulic head difference between the upper end and the lower end of the chamber. The hydraulic pressure distribution in the chamber of the proposed permeameter can be finely controlled by adjusting the elevation of the cylinder inlet to be placed at a lower position than the hydraulic head in the chamber. This improves the accuracy of measurement of flow rate and hydraulic gradient with the permeameter. ConclusionThe new CP module enables K testing at low permeability geological material for various applications, including measurements that would otherwise not possible. Instrumentation developments that are currently in progress will enable real time monitoring of several parameters including moisture content. Current research includes solute transport modelling to evaluate the effect different influent chemical compositions have on the hydraulics properties of different aquitard materials.

Comments on health and safety Must use hand glove made of cloth because the oven knob become hot too once switched on. Use safety shoes when handling or conducting proctor compaction test because the hammer is would injure legs. Beware of slippery floor. Should wear mask to avoid dust.

References

Prakash, K. and Sridharan, A. (2014). "Discussion of Atterberg Limits and Remolded Shear StrengthWater Content Relationships." Geotechnical Testing Journal, 10.1520/GTJ20140008, 20140008. http://ascelibrary.org/doi/abs/10.1061/(ASCE)1090-0241(2005)131%3A3(402)

Seed, H.B. (1967). "Fundamental Aspects of the Atterberg Limits". Journal of Soil Mechanics and Foundations Div., 92(SM4), Retrieved fromhttp://trid.trb.org/view.aspx?id=38900

Landon M. K., Rus D. L. & Harvey F. E. Comparison of instream methods for measuring hydraulic conductivity in sandy streambeds. Ground Water 39, 870885 (2001).

Day, Robert W. (2001). Soil Testing Manual: Procedures, Classification Data, and Sampling Practices. New York: McGraw Hill, Inc. pp. 293312.2