Constant Head Permeability, Sieve Analysis and Liquid Limit Practicals

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Course
ENB272
Professor
All Professors
Semester
Fall

Description
Constant Head Permeability, Sieve Analysis and Liquid Limit Practicals ENB272 – Geotechnical Engineering Tim Starkey n8588163 Table of Contents Practical 1 – Sieve Analysis Test....................................................................................3 Equipment......................................................................................................................................3 Materials.........................................................................................................................................3 Procedure.......................................................................................................................................3 Calculations and Discussions..................................................................................................3 Practical 2 – Constant Head Permeability Test........................................................5 Equipment......................................................................................................................................5 Materials.........................................................................................................................................5 Procedure.......................................................................................................................................5 Calculations and Discussions..................................................................................................5 Practical 3 – Liquid Limit Test........................................................................................7 Equipment......................................................................................................................................7 Materials.........................................................................................................................................7 Procedure.......................................................................................................................................7 Calculations and Discussions..................................................................................................8 Appendices.........................................................................................................................10 2 Practical 1 – Sieve Analysis Test This test is carried out to determine the percentages present of various sizes (governed by sieves used) of particles in soil (generally on soil particles coarser than 75μm) Equipment The equipment required to undertake this test were:  Set of sieves with different mesh opening sizes  Brush to clean sieves  Electronic balance  Shaker to shake that stack of sieves  Oven to dry soil  Watch (or Stopwatch) Materials This practical required the following materials:  Dry Sand Procedure To perform this test, the following procedure was followed: a. Select a set of sieves and clean them b. Measure the weight of each sieve and record c. Stack the sieves in the shaking apparatus d. Obtain about 700 ~ 1000g of dry sand and pour it into the top sieve in the stack (Note: measure and note exact mass of sand before putting it into the top sieve) e. Close the top sieve by using a lid and shake the stack of sieves for 3 ~ 5 min f. Measure the mass of each sieve with retained sand and record the values g. Remove the retained sand in each sieve and clean sieves Note: You are provided oven-dried sand for this test and can assume zero water content Calculations and Discussions (1) Data Sheet Dry Mass of Test Sample = 999g Sieve Mass Mass of Mass of Cumulative Cumulative % Size of sieve + retained retained % retained passing (mm) Sieve retained soil (g) mass (g) soil (g) 4.75 1004 1025 21 21 2.1 97.9 2.36 1060 1156 96 117 11.7 88.3 1.18 961 1204 243 360 36.1 63.9 0.6 921 1158 237 597 59.8 40.2 3 0.425 835 992 157 754 75.5 24.5 0.3 790 897 107 861 86.2 13.8 0.212 774 868 94 955 95.7 4.3 0.15 765 801 36 991 99.3 0.7 0.075 773 779 6 997 99.8 0.2 Pan 791 792 1 998 100 0 (2) See Appendix 1 for ‘Percentage Finer vs Particle Size’ (3) Using the ‘Percentage Finer vs Particle Size’ graph, the valu10 f30 D50 D , D and D60an be obtained. See Appendix 1 for how these values were obtained. D10 0.28mm D = 0.49mm 30 D50 0.79mm D60 1.05mm (4) The permeability of this test soil can be calculated using Henzan’s equation: Therefore: (5) Using the different values of ‘D’, the Coefficient of UniUormity (C ) and the Coefficient of CurvatureZ(C ) can be calculated for this sample using: And Therefore, U is calculated as: And CZis calculated as: (6) Using the Unified Soil Classification System (USCS), this soil sample can be given a classification according to its grain size. This sample is classified as Poorly Graded Sand because more than 50% of its coarse fraction is smaller than 2.36mm and its percentage of Fines is smaller than 5%. This classified it as Clean Sand but it couldn’t be graded as Well Graded Sand as Uts C Znd C were too small (see Appendix 2). 4 (7) Due to the grading of the soil sample, there are limited applications for this material. As it couldn’t be graded particularly well, the sample would not be appropriate for aggregate as there is a limited range of particle size. However, a more appropriate use for this graded soil is Sand Fill, the use of sand to fill in large spaces. Because of the small yet uniformed grain sizes, the soil could be easily compacted down to levelled ground, ideal for laying a slab for construction. Another use for Poorly Graded Sand is a natural sand filter. These filters are used in a large variety of water filtration situations on and off construction sites. Placed in water run offs, sand filters remove a large majority of the potential biohazard waste out of water flowing of a construction site. Stopping hazards such as litter, chemicals and oils from running into water streams and preventing contamination. Practical 2 – Constant Head Permeability Test Equipment The equipment required to undertake this test were:  Permeameter  Watch (or Stopwatch)  Electronic Balance  Graduated Cylinder  Thermometer Materials This practical required the following materials:  Sand (obtained from the same batch used for sieve analysis) Procedure a. Adjust the height between the constant head water tank and the permeameter cell b. The cell is then subjected to water flow under a constant head c. The test should commence with a small flow by opening the inlet and then the outlet taps a little; adjust these to get a constant and steady head difference on the manometers d. Using the graduated cylinder, measure the volume of water collected in about 10 sec and then measure the temperature of collected water e. Repeat step d for about 20 sec and 30 sec Calculations and Discussions (1) Data Table Internal diameter of 7.35 cm Permeameter cell (D) Height of Soil Specimen 19 cm Dry mass of Soil 1340g Reading of manometer 1 (H ) 1 16.5cm 5 Reading of manome
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