3400 Lab 1

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Georgia Institute Of Technology *

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3400

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Civil Engineering

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Apr 3, 2024

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Georgia Institute of Technology School of Civil and Environmental Engineering Soil Mechanics Laboratory MEMORANDUM To: Emre Duman Date: January 25, 2024 From: Sachinshripadh Dasu, A31 Lab Partners: Stephen Grafius, Marty Robert James Jr., Ashley Eun Joo Jhun Subject: CEE 3400 Sample Description: Name: Piedmont Red Clay Source: In-Situ Condition: Dry Visual Classification and Unified Symbol: SM Remarks: Piedmont Red Clay was used as a soil sample for Part 1 of this laboratory experiment. Test Procedure: Test Procedures: ASTM D2487: Standard Classification of Soils for Engineering Purposes (Unified Soil Classification System) ASTM D6913: Standard test Methods for Particle-Size Distribution (Gradation) of Soils Using Sieve Analysis ASTM D2499: Standard procedure for Description and Identification of Soils (Visual-Manual Procedures) The Visual manual Classification of Soils laboratory consists of two different lab procedures, or sections. The first section of the laboratory is Part 1: Grain Size Analysis, and the second part of the laboratory is Part 2: Classification. In Part 1, the Unified Soil Classification System is used; this system gives each soil type a two letter designation. In addition, ASTM D24287 describes the procedure to determine the classification using USCS. For the procedure of Part 1, the ASTM D6913 standard is used for the sieve analysis. For the procedure of Part 1, the 3 inch, ¾ inch, #4, #10, #40, and #200 sieves are used. They are first cleaned using a soft brass brush, then weighed using a scale to determine the mass of each sieve and pan. Then, 200 grams of dry soil are collected and poured into the sieve, where a shaker is used to separate the particles. The sieve is disassembled, and each sieve and pan are weighed out to determine the mass of the sieves and mass retained on each sieve. The sieves are then cleared and cleaned, and it is then determined that the final mass of the soil is within 2% of the initial mass, therefore, a second test does not need to be conducted. For the procedure of Part 2, ASTM D2488 is used as a standard procedure for the classification of coarse-grained versus fine-grained soils. Six different soil samples are analyzed and classified based on soil type (gravel, sand, silt, and clay) and descriptive information (angularity, shape, color, odor, and moisture content). Of these six samples, the last two samples are fine-grained soils that will be analyzed and categorized based on dry strength,

dilatancy, toughness, plasticity, and soil classification. There were no modifications or deviations in the test procedures when compared to the handout throughout the entirety of the laboratory. Test Results: 1. The table below, Table 1: Part 2: Visual-Manual Classification of Soil Worksheet Table, describes each of the soils using the visual-manual worksheet. Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 Soil Type Gravel Sand Sand Sand Silt Sand Angularity Subangular Rounded Subrounded Rounded Subrounded Rounded Shape Flat & Elongated - - - - - Color Red, gray, orange Cream Light Gray Red, orange White Cream Odor - - - - - - Moisture Content Dry Dry Dry Dry Moist Dry Table 1: Part 2: Visual-Manual Classification of Soil Worksheet Table 2. The table below, Table 2: Part 1 Laboratory Data Table, provides data recorded in the laboratory. The table provides data on sieve size, sieve or pan mass, mass sieve + soil retained, and mass soil retained. Sieve # Sieve Size (mm) Sieve or Pan Mass (g) Mass Sieve + Soil Retained (g) Mass Soil Retained (g) 3 inch 76.2 458.3 485.2 0.1 ¾ inch 19.1 514.4 514.4 0 #4 4.75 774.3 805.0 30.7 #10 2.06 471.5 498.3 26.8 #40 0.425 339.4 410.7 71.3 #200 0.074 301 359.9 58.9 Pan - 371 382.9 11.9 Σ = 199.7 grams (Sum of Total Remaining Mass) Table 2: Part 1 Laboratory Data Table The table below, Table 3: Part 1 Data Analysis Table, contains information regarding sieve #, weight retained, cumulative weight, and retained and cumulative % retained and passing. Some of the data in Figure 3 is calculated based on information from Figure 2.

Sieve # Sieve Size (mm) Mass Soil Retained (g) % Mass Retained on Sieve (%) Cumulative % Retained (%) Percent Finer Than Each Sieve 3 inch 76.2 0.1 0.05 0.05 99.95 ¾ inch 19.1 0 0 0.05 99.95 #4 4.75 30.7 15.35 15.40 84.60 #10 2.06 26.8 13.40 28.8 71.20 #40 0.425 71.3 35.65 64.45 35.55 #200 0.074 58.9 29.45 93.9 6.1 Pan - 11.9 5.95 99.85 0.15 Table 3: Part 1 Data Analysis Table Sample calculations for the values in the table are provided below. Mass Soil Retained = (Mass sieve + Soil Retained) – (Sieve or Pan Mass) = 805.0 – 774.3 = 30.7 % Mass Retained on Sieve = ((Mass Soil Retained)/(Sum of Total Remaining Mass))*100 = (.1/199.7)*100 = 0.05% Cumulative % Retained = Σ % Mass Retained on Sieve = 15.35 + 0.05 = 15.40 Percent Finer Than Each Sieve = 100% - (Cumulative % Retained) = 100% - 0.05% = 99.95% The graph below, Figure 1: Grain Size Distribution, provides the grain size distribution curves with appropriate semi-log axes. Figure 1: Grain Size Distribution 3. The following calculations are for the Coefficient of Uniformity and the Coefficient of Curvature for the grain size distribution. The D10 and D50 values are also calculated. The following table also provides effective particles sizes based on the grain size distribution of Figure 1, which is shown above. The effective particles sizes are calculated based off of linear interpolation. Sample Calculations are shown below. D 10 D 30 D 50 D 60 Effective Particle Size (mm) 0.118 0.356 1.088 1.546 99.95 99.95 84.6 71.2 35.55 6.1 0 10 20 30 40 50 60 70 80 90 100 0.01 0.1 1 10 100 % Finer Sieve Opening Diameter (mm)

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Table 4: Effective Particle Size Table Coefficient of Curvature = 𝐷𝐷 30 2 𝐷𝐷 10 𝐷𝐷 60 = ( 0 . 356 ) 2 0 . 118∗ ( 1 . 546 ) = 0.695 Coefficient of Uniformity = 𝐷𝐷 60 / 𝐷𝐷 10 = 13.102 4. The percentages of gravel, sand, and fines can be calculated for the soil sample tested in Part 1. Gravel particles are retained until the #4 sieve. Sand particles are retained until the #200 sieve, and fines are the particles that are left over in the pan. The percentage of gravel in the soil sample is 0.05%. The percentage of sand in the soil sample is 93.85%. The percentage of fine in the soil sample is 6.1%. 5. The sample tested in this laboratory for Part 1 is defined as well-graded. Well-graded soil is defined as a soil that has a wide range of particles sizes that represent soil that range from the #40 to #200 sieves. The grain size distribution curve also matches this assertion (McLaren 1981). 6. The table below classifies each soil sample from Part 2 of this laboratory. Group symbols and group names are used for each soil. Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 Sample Name GP SP SP SP ML SL Soil Type Gravel Sand Sand Sand Silt Sand Angularity Subangular Rounded Subrounded Rounded Subrounded Rounded Shape Flat & Elongated - - - - - Color Red, gray, orange Cream Light gray Red, orange White Cream Odor - - - - - - Moisture Content Dry Dry Dry Dry Moist Dry Table 5: Part 2: Visual-Manual Classification of Soil Worksheet Table Sample 5 Sample 6 Dry Strength Low Medium Dilatancy Slow Rapid Toughness Low Low Plasticity Low Medium Soil Classification Low Plasticity Silt MH Low Plasticity Silt MH Figure 4: Part 2: Identification of Fine-Grained Soils Table Analysis and Discussion (40 points) The purpose of this laboratory is to identify and classify different types of soils. Part 1 of this laboratory procedures uses a sieve analysis (ASTM D6913) to conduct a grain size analysis. A sieve analysis is conducted to quantify the relative distribution of grain sizes within a soil sample. Typically, only the coarse grained portion (larger than a #200 sieve) of a soil sample is analyzed using sieve analysis. However, the method is still applicable if the soil has a small fraction of grain sizes smaller

than the #200 sieve. Part 2 of this laboratory identifies the differences between coarse-grained (gravel and sand) and fine-grained soils (silt and clay). In Part 2 of the laboratory, ASTM D2488 is used as a standard procedure to determine the angularity, shape, color, odor, and moisture content of different soil types. Dry strength, dilatancy, toughness, and plasticity are used to identify and classify two different samples of fine-grained soils. Based on the procedures followed in this laboratory, it does seem as an accurate way to classify and identify various types of soil. Three possible sources of error and problems within the test would be human error involved with weighing the sieves in Part 1, human error with the classification of soils in Part 2, and scale error while weighing the sieves in Part 1. While weighing out the sieves, some sieves still had larger chunks of particles stuck in them that could not be pushed out while cleaning out the sieves. Some of the sieves’ mass were estimated as the scales would not display one single number but would rather change throughout the weighing process. For example, the 3 inch sieve would display as a number from anywhere from 458.2 to 458.4. Due to this, a best estimate was taken for a few sieves that displayed these problems. The human error during Part 2 would amount to the error in classification of the samples. The angularity was subjective for these samples, and for the fine-grained samples, the soil classification was debated heavily before deciding upon the given choices. There are numerous potential engineering applications that rely on these tests. Soil analysis is an important process of geotechnical engineering that can be used for construction as well. It can be important to understand the type of soil an engineer is working with to better design a structure that will be able to place a load on the given soil. Grain size distribution is also important for drainage and filter systems. Grain size analysis and distribution can also impact other industries, such as the pharmaceutical, food, and cosmetics industries, and clays are an important part of all of these industries. Pharmaceuticals and cosmetic industries all use clays for various gel and creams, and the food industry also relies on particle size analysis for water filtration systems. 1. On the measured grain size distribution, the shaking time can affect the sieve analysis. A longer shaking time would allow for particles that are stuck in the sieves to fall out and allow for any particles to better settle based on their size. A higher shaking time would also allow for any loosely packed rocks or larger particles to break up due to mechanical weathering and allow for these particles to settle in the lower sieves. A lower shaking time would have the opposite effects, as particles in the soil sample would not be able to fully settle. The results would display in a grain size distribution graph as having a larger mass (or percent of soil sample) at the bottom of the graph, where the finer particles are settled. 2. The particle shape would have a large effect on the grain size distribution. Angular shaped particles would not be able to easily pass through sieves, despite theoretically being able to. This is due to the fact that the shape would making it harder for particles to pass through the square shaped sieve opening due to the angular and jagged edges of the particles. A longer shaking time would be able to alleviate tis issue as the increased time would allow for more particles to fully settle through the sieve analysis. 3. Particle shape does have an effect on soils sample strength. This is shown with how well soils can be compressed and packed together. Rounded sand particles are not able to pack together as tightly as angular sands. Due to this loose packing, rounded sands would not be as strong as angular sands (Matthews 1991). 4. Grain size distribution affects the minimum void ratio (maximum density) achievable as finer particles are able to be tightly packed which allows for smaller void spaces in the soil samples. Larger particles would have larger void spaces in between particles in the soil samples, which would man a lower density. Soil samples with finer particles would be able to have a higher

density in the soil sample, as compared to a soil sample of mainly larger particles. Therefore, a poorly graded, course-grained soil sample would have a lower density than a well-graded sample with a good distribution of course-grained and fine-grained soil sample. Concluding Remarks: After the laboratory experiment for Part 1, it can be concluded that the soil sample tested in the sieve analysis is a soil that is well-graded, with a Coefficient of Uniformity of 13.102, and a Coefficient of Curvature of 0.695. It is also determined that this sample mainly consists of sand, with some amount of gravel and fines particles. Part 2 of the laboratory experiment consisted of classifying and identifying six different soil samples based on the Visual-Manual worksheet. There were also no significant modifications of the traditional test procedures, and all ASTM standard practices were followed while conducting the experiments in this laboratory. There are limitations to the procedures in Part 1, as the experiment is mainly focused on coarse-grained soil particles. There are also limitations in Part 2, as the Visual-Manual worksheet procedures that cause identification error due to human error. There are various instances where properties of various soils can be disputed, which would cause confusion on accurately identifying the various soils. Despite these limitations, these procedures are important for engineers as they can be used in a variety of industries, not just the civil industry, that rely on grain size distribution and particle size. References: Budhu, M., (2015), “Soil Mechanics Fundamentals – Imperial Version,” John Wiley & Sons, Ltd. Matthews, M. D. (1991). The effect of grain shape and density on size measurement. Principles, Methods and Application of Particle Size Analysis , 22–33. https://doi.org/10.1017/cbo9780511626142.004 McLaren, Patrick. (1981). An interpretation of trends in grain size measures. SEPM Journal of Sedimentary Research , Vol. 51 . https://doi.org/10.1306/212f7cf2-2b24-11d7- 8648000102c1865d Appendix: The data below was recorded in the lab and is presented in this laboratory report.

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Sieve # Sieve Size (mm) Sieve or Pan Mass (g) Mass Sieve + Soil Retained (g) Mass Soil Retained (g) 3 inch 76.2 458.3 485.2 0.1 ¾ inch 19.1 514.4 514.4 0 #4 4.75 774.3 805.0 30.7 #10 2.06 471.5 498.3 26.8 #40 0.425 339.4 410.7 71.3 #200 0.074 301 359.9 58.9 Pan - 371 382.9 11.9 Σ = 199.7 grams (Sum of Total Remaining Mass) Sieve # Sieve Size (mm) Mass Soil Retained (g) % Mass Retained on Sieve (%) Cumulative % Retained (%) Percent Finer Than Each Sieve 3 inch 76.2 0.1 0.05 0.05 99.95 ¾ inch 19.1 0 0 0.05 99.95 #4 4.75 30.7 15.35 15.40 84.60 #10 2.06 26.8 13.40 28.8 71.20 #40 0.425 71.3 35.65 64.45 35.55 #200 0.074 58.9 29.45 93.9 6.1 Pan - 11.9 5.95 99.85 0.15 Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 Soil Type Gravel Sand Sand Sand Silt Sand Angularity Subangular Rounded Subrounded Rounded Subrounded Rounded Shape Flat & Elongated - - - - - Color Red, gray, orange Cream Light Gray Red, orange White Cream Odor - - - - - - Moisture Content Dry Dry Dry Dry Moist Dry Sample 5 Sample 6 Dry Strength Low Medium Dilatancy Slow Rapid Toughness Low Low Plasticity Low Medium Soil Classification Low Plasticity Silt MH Low Plasticity Silt MH

3400 Lab 1

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