BRIAN PATRICK ODHIAMBO:TITLE: REPORT ON SIEEVE ANALYSIS

BRIAN PATRICK ODHIAMBO DBCE/100J/2018 BUILDING AND CIVIL ENGINEERING DEPARTMENT OF BUILDING AND CIVIL ENGINEERING UNIT NAME: SOIL MECHANICS ONE UNIT CODE: EBCE 2205 TITLE: REPORT ON SIEEVE ANALYSIS DATE: 14-MAR-2019  INTRODUCTION. Particle size analysis for soils is performed in order to determine the percentage of different grain sizes contained within a soil sample in accordance to BS1377-2. After the experiment, this report concludes that the soil sample that was analyzed is uniformly distributed after it passed the Unified Soil Grading Criteria. The errors in the experiment performed are assumed negligible because of the small discrepancy in the results of the two trials performed. Objectives  To acquire the particle size distribution of the soil sample in accordance to BS 1377-2: Standard Test Method for Particle-Size Analysis of Soils  To produce data with acceptable error of less than 2%  To generate a semi-logarithmic plot that displays the particle size distribution of the soil and to identify the grading of the soil using the data points on the Graph. II. Materials  Soil Sample (1034grams for first sample and 1013grams for second sample)  Scale  Sieves  Oven Procedure: Prepare soil samples that have been oven-dried for at least 24 hours. Weigh and record the mass of the sample that have been prepared. Prepare asset of clean sieve ranging from sieve 2.36 mm-0.150mm and an empty bottom pan. Ensure that the sieve opening sieve chosen are uniformly distributed i.e. from the largest diameter to the smallest diameter. Weigh and record the masses of each sieve and the bottom pan that will be used in the experiments. Stack the sieve in the descending order i.e. in these experiment sieve 2.36mm- sieve 0.150 from top to the bottom just above the pan respectively. Carefully pour the soil sample on top of the stacked sieve and then cove the top sieve with its lid. Put in the vibrating or shaking machine for about 7-14 minutes Allow the stack to rest and allow the lightweight samples to settle. Carefully remove the sieve from the stack and weigh and record their corresponding masses. Compute the percentage error of the initial mass of the soil sample to the computed sum of the soil sample retained. Repeat the whole procedure for the second experiment, for the first is considered as unsatisfactory and hence must be repeated. Particle size distribution graph is then obtained by plotting the sieve opening size on the x-axis versus the percent passing on the y-axis as presented below: First Data and Results (mass 1034gramms) Sieve size Mass retained (g) Accumulative mass passing (g) % accumulative mass retained % accumulative mass passing. 2.36 14 14 1.35 98.65 1.18 92 106 10.22 89.78 0.850 177 283 27.30 72.7 0.600 331 614 59.20 40.79 0.425 183 797 76.85 23.15 0.350 105 902 86.98 13.02 0.212 92 994 95.85 4.15 0.150 27 1021 98.46 1.54 Pan 16 1037 100 0 . Second data and results (mass 1013gramms) Sieve size Mass retained (g) Accumulative mass passing (g) % accumulative mass retained % accumulative mass passing. 2.36 15 15 1.5 98.95 1.18 89 104 10.34 89.66 0.850 175 279 27.73 72.27 0.600 345 624 62.03 37.97 0.425 198 822 81.71 18.29 0.350 73 895 88.97 11.03 0.212 83 978 97.22 2.78 0.150 19 997 99.11 0.89 Pan 9 1006 100 0 In order to classify the grading of the soil sample, the coefficient of uniformity and curvature were calculated as follows: Coefficient of uniformity ( D60/D10) Coefficient of curvature (D30^2/D60* D10) Wherein is the coefficient of uniformity, is the coefficient of curvature, and are particle diameters at 60%, 30%, and 10% passing. For Trial 1: Coefficient of uniformity = (D60/D10) 0.60/ 0.29 =2.07 Coefficient of curvature = ( D30)^2/ (D10* D60) (0.5)^2/ (0.29* 0.60) = 1.44 For Trial 2: Coefficient of uniformity = (D60/D10) 0.65/0.31 = 2.1 Coefficient of curvature = ( D30)^2/ (D10* D60) (0.5)^2 / (0.31* 0.65) = 1.24 Analysis and Discussion Particle size analysis is widely used in classification of soils. The data acquired from particle size distribution curves is used in the design of filters for earth dams and to determine suitability of soil for road construction, air field, and others. Also, information obtained from particle size analysis is useful in describing the permeability, compaction, and other properties of soils. The experiment performed focuses on generating the particle size distribution of the soil sample. The generated particle size distribution graph is used in a lot of ways such as identifying the grading of the soil and the percentage of course materials and the fines. As shown in the above section we were able to calculate the coefficient of uniformity and curvature which were both used to conclude whether the soil is uniformly graded. The coefficients will be compared based on the Unified Soil. Grading Criteria which is presented in the table below. CRETERION MATERIAL GRAVEL SAND UNIFORMITY CU> 4 CU> 6 CURVATURE 1<Cc< 3 1<Cc <3 Since the soil particles used most passed sieve #2.36, the soil sample is thus considered as containing of mostly of sands. Checking the values computed for the two trials, we see that both coefficient of uniformity, of the two samples which were 2.07 and 2.10 are less than 6. For the coefficient of curvature we see that both values which where 1.44 and 1.24 are both more than 1 but less than 3. And because the two trials of the soil samples was not able to pass the criteria for coefficient of curvature but pass the criteria for coefficient of uniformity, we then conclude that the soil is non-uniformly graded soil A non-uniformly graded soil, like the soil sample, generally does not work best as a construction material. This is because of the poor arrangement of the soil particles that does not lessen the number of voids and improves compatibility. Conclusions and Recommendations After thorough analysis it is concluded that the soil sample is non-uniformly graded and probably does not work best as a construction material. Also, it is inferred that because of the low number of fines, Atterberg limit which describes the fines will not be a great concern in contrasts to the physical properties of the sandy particles that greatly affects the strength of the soil sample. Note that because of the laboratory constraints, the hydrometer analysis which is used in order to identify the particle size distribution of the soil was not performed and thus the particle size distribution that was generated in this experiment is not complete. Errors in the experiment performed were assumed to be almost negligible. Reference Engineers Daily. AASHTO Soil Classification System. Retrieved in http://www.engineersdaily.com/2011/03/aashto-soil-classification-system.html Army Engineer. General Engineering Properties. Retrieved in http://armyengineer.tpub.com/En5341a/En5341a0107.html Concrete Counter Top Institute. Aggregate Gradation. Retrieved in http://www.concretecountertopinstitute.com/blog/wpcontent/uploads/2012/04/agg regate_gradation. Das, Braja M. Principles of Geotechnical Engineering. Published on 2002. E-book.