The USC and AASHTO soil classifications test Question

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It's only three pages, not that long. I would like to get help from someone who is expert in Geotechnical Engineering!

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TEST NO. 1: TAKE HOME 1. Describe the USC and AASHTO soil classifications and list one similarity, one difference, one advantage, and one disadvantage of each system. 2. Why do we have soil classification systems? What use are they? 3. Develop a conceptual visual model of a soil element? Describe how you use this model to envision soil strength and volumetric changes of the soils element? 4. Draw the phase diagram and label the various elements of the diagram. Why is the phase diagram useful in the study of geotechnical engineering? Draw two phase diagrams for a soil having the same amount of solid material. One of the phase diagrams is at its liquid limit and the other is at its plastic limit. 5. Define the following: void ratio, water content, degree of saturation, total unit weight, dry unit weight, and submerged unit weight. 6. Derive the following two relationships: Se=wG SASATURATION e-VOID RATIO wa water content es Edry G-specike Gnavery on SOLID sw - unit weight of water Edy: dry density 7. What is the significance of the No. 4 sieve, the No. 40 sieve, the No. 200 sieve, and a particle size equal to 0.002 mm. بالای -1 8. Given the following soil weight data of a soil that passed a No. 40 sieve: Liquid limit test results Weight of wet soils and can = 33.86 g Weight of dry soil and can = 25.4 g Weight of can = 11.38 Plastic limit test results Weight of wet soils and can = 25.04 g Weight of dry soil and can = 20.8 g Weight of can = 10.2 g a. Determine the liquid and plastic limits of the soil. b. If the soil had a clay content of 20 percent determine the Activity ratio of the soil. c. Determine corresponding liquid limit, plastic limit, and plastic index of the soil if it was 100 percent clay. d. If the limiting void ratio that a plastic limit or liquid limit could be obtained was 0.8, determine the percent of clay that would define the point at which a soil similar to the one tested would corresponding to where the plastic limit could not be determined. What is the corresponding liquid limit at the limiting plastic limit? What was the plastic index at the limiting plastic limit clay content? 9. Draw the phase diagram of a soil that has oversize material, coarse material from No. 4 sieve to No. 40 sieve, fine sands, silts, and clays. 10. Draw a soil element that has just a coarse grain particle skeleton structure. Draw a soil element that has primarily a soil matrix made up of fines passing the No. 200 with coarse grain particles suspended in the matrix. Draw a soil element that has a coarse grain particle skeleton structure with its voids filled with finer soils. Sketch the grain-size distributions of these three soil elements. 11. What is the difference between a soil that classifies as a SC and as a CL soil? Can the SC soil behave as the CL and if so why? Can a soil that classifies as a CL act or behave very similar to a soil that is classified as an ML and if so why? 12. Using the plasticity chart, draw or sketch the relationship between liquid limit and plastic index of to the point where you believe the liquid and plastic index tests would have no meaning. a soil mixture that starts with 100 percent clay and then has a fine sand added to it. Extend the sketch 13. Consider that you could pour sand that had a specific gravity of 2.64 into any volume or container such that the resulting soil would have a void ratio of 0.8. Develop a method that you could use to determine the total unit weight, dry unit weight, and moisture content of a soil at the ground surface or at the exposed surface in a test pit that was dug. Outline the calculations you would use to determine the total unit weight, dry unit weight, and moisture content of a soil
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Explanation & Answer

Here is your assignment :).

TEST NO. 1: TAKE HOME
1. Describe the USC and AASHTO soil classifications and list one similarity, one difference, one
advantage, and one disadvantage of each system.
Answer:
USC: This applied to most unconsolidated material represented by two letter symbol: 𝐺 =
𝑔𝑟𝑎𝑣𝑒𝑙, 𝑆 = 𝑠𝑎𝑛𝑑, 𝑀 = 𝑠𝑖𝑙𝑡, 𝐶 = 𝑐𝑙𝑎𝑦 𝑂 = 𝑜𝑟𝑔𝑎𝑛𝑖𝑐. Second letter: 𝑃 =
𝑝𝑜𝑜𝑟𝑙𝑦 𝑔𝑟𝑎𝑑𝑒𝑑 𝑊 = 𝑤𝑒𝑙𝑙 𝑔𝑟𝑎𝑑𝑒𝑑, 𝐻 = ℎ𝑖𝑔ℎ𝑙𝑦 𝑝𝑙𝑎𝑠𝑡𝑖𝑐, 𝐿 = 𝑙𝑜𝑤 𝑝𝑙𝑎𝑠𝑡𝑖𝑐𝑖𝑡𝑦.
AASHTO: This classification depends on three different soil properties: particles size
distribution, liquid limit, and plasticity index.
Similarity: Both classification considers finding the percentage of particles of soil in different
soil. The analysis is intensive in case of AASHTO a whole sieve analysis for low sieve is done.
Difference: USCS classification is based on sieve no 200, plasticity index and AASHTO is based
on plasticity index and group index value. In case of USC classification, coefficient of
uniformity and coefficient of curvature is used which helps to classify the soil to be well or poor
depending on their value and whether it is gravel or sand.
Advantage: UCS gives an idea about the distribution of larger sized particles and there range
with help of coefficient of curvature and coefficient of uniformity with help of AASHTO, we
have a lot of different groups for a single soil.
Disadvantage: AASHTO requires intensive or time talking sieve analysis as well as various other
limits such as liquid and plastic limit making it a very lengthy procedure. In UCS classification,
knowing the soil type is just dependent on soil size distribution and silt size, the factor other than
that are not kept in consideration.

2. Why do we have soil classification systems? What use are they?
Answer:
We need Soil classificatio...


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