Answers to Questions 1. What is the purpose of grain size analysis? Particle size distribution, also known as gradation, refers to the proportions by dry mass of a soil distributed over specified particle-size ranges. Gradation is used to classify soils for engineering and agricultural purposes, since particle size influences how fast or slow water or other fluid moves through a soil. 2. What is grading curve? Grain size is plotted on the horizontal scale and percentage the vertical scale. The coarsest grain size is always plotted on the left and finest on the right. 3. Under what conditions should you use wet sieving instead of dry sieving? Sieving can be performed in either wet or dry conditions. Dry sieving is used only for soil with a negligible number of plastic fines such as gravels and clean sands, whereas wet sieving is applied to soils with plastic fines. 4. On which basis do you select the number and opening opening of sieves for the sieve analysis of a given soil? The choice of sieves usually depends on experience, judgement and the intended applications of grain size analysis. It will depend on the soil to be tested. A good selection is to have a nest composed of each sieve having an opening approximately one-half of the coarser sieve above it. 5. A mass of volcanic ashes with highly crushable grains is brought to the laboratory. What precaution do you take to determine its grain size distribution? Ash samples samples should be be dried in the oven oven first, then then sieve at least one one interval interval down to 63 . 6. On what range of particle size does the sieve analysis apply? The sieve analysis applies to the gradation of soil between 3 inches and #200 sieve. 7. Is it possible to carry out sieve analysis on a sample of clay? It is not possible to carry out sieve analysis on a sample of clay because it is fine grained. A hydrometer should be used in analyzing this type of soil.
Introduction
Principles of the Experiment: The sieve analysis determines the grain size distribution curve of soil sample by passing them through a stack of sieves of decreasing mesh opening sizes and by measuring the weight retained on each sieve. Sieving can be performed in either wet or dry conditions. Dry sieving is used only for soil with a negligible amount of plastic fines such as gravels and clean sands, whereas wet sieving is applied to soils with plastic fines. According to the British Standard, dry sieving may be carried out only on materials for which this procedure gives the same results as the wet-sieving procedure. This means that it is applicable only to clean granular materials, which usually implies clean sandy or gravelly soils that is, soils containing negligible amounts of particles of silt or clay size. Normally the wetsieving procedure should be followed for all soils. If particles of medium gravel size or larger are present in significant amounts, the initial size of the sample required may be such that riffling is necessary at some stage to reduce the sample to a manageable size for fine sieving. In this experiment, the particulate nature of soil was greatly observed. It was also shown that certain classifications in soil can be done through sieve analysis. The accuracy of this experiment is very much dependent on the sieve arrangement. The arrangement of sieves must be in decreasing mesh openings from top to bottom. This is very useful in order to separate the particles from coarser to finer. Lastly, It was observed that for particles having sizes larger that the sieve opening to which it will be retained. On the other hand, those with smaller sizes were able to pass through. This phenomenon is the basic reason on how particles were separated. Knowing the distribution of soil is best applied in making engineering judgements towards total soil condition. The distribution of soil components is one important soil profile applied in the field of foundation engineering. This analysis on grains is also utilized in part of the specifications of soil for airfields, roads, earth dams, and other soil embankment construction.
Interpretation of the Results: To get the needed results of the experiment we used a set of sieves to get the percent finer of the given soil sample. We used manual sieve shaking because the sieve shaker that is available in the laboratory was out of order. Based on the results of the experiment, the sieve that has the highest retained weight is at sieve 200 with 148.29 grams, a percent finer of 14.36 percent.
Application: ASTM D422 denotes the standard test method for particle-size analysis of soils. The particle-size distribution of a soil is the major classification test, and a knowledge of the distribution will also prove helpful in making a number of other engineering judgements about a soil and has many applications in foundation engineering. Grain-size analysis is also the utilized in part of the specifications of soil for airfields, roads, earth dams, and other oil embankment construction.
Conclusion In this experiment, we had successfully determined the grain sizes contained within a soil sample using sieve analysis. By performing the procedure carefully, the sum of the retained was close to the initial soil sample. The possible sources of errors could be from the soil sample if not properly sieved. Inaccurate weight of retained mass might occur. To conclude, the distribution of different grain sizes affects the properties of soil. In soil classification, grain size analysis is required because it provides the grain size distribution.
References Basic Civil Engineering. (2017, June 22). Sieve Analysis - Particle Size Analysis . Retrieved from Basic Civil Engineering: http://www.basiccivilengineering.com/2017/06/sieve-analysistest.html Das, B. M. (2006). Principles of Geotechnical Engineering. Stamford: Cengage Learning. Murthy, V. N. (n.d.). Geotechnical Engineering: Principles and Practices of Soil Mechanics and Foundation Engineering. New York : Marcel Dekker . QsArticle. (2012, June 2). Gradation of Fine Aggregate by Sieve Analysis . Retrieved from Qs Article: https://www.qasimshinwari.com/gradation-of-fine-aggregate-by-sieve-analysis/ Rahman, F. U. (2009, March 19). Particle Size Distribution. Retrieved from The Constructor: https://theconstructor.org/geotechnical/particle-size-distribution-of-soil-hydrometermethod/2775/ Sharma, K. C. (2013, July 23). Sieve Analysis of Aggregates. Retrieved from Civil Engineeiring Portal: http://www.engineeringcivil.com/sieve-analysis.html Suryakanta. (2103, May 14). Sieve Analysis of Soil . Retrieved from Civilblog.org: http://civilblog.org/2013/05/14/sieve-analysis-of-soil-is-2720-part-4-1985/
