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Published byErnest Gilmore Modified over 9 years ago
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Soil and weathering lab Niti Mankhemthong 15/10/10
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-Roundness? - Grain size? -Sorting? Channel flow vs flow velocity vs sediment load & clasts
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Speed water flow and Size???
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Coarse-grained textures Texture Grain Sorting Grain Rounding
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Grain Size
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Sorting or Graduation
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Grain Roundness or Particle shape
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Look at a descriptive handout
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Observational data in terms of fluid velocity and grain size:
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~ 100 g Weight the dry clay (sieve no. 45 (~0.33 m)) Mixed with little water (2 spoon water ) 1 cm height
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TAP!! 25 TIMES If you do not get Weight the final wet samples Add ½ spoon water each turn
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Weight of wet sample and bowl Weight of day sample Weight sample – dry sample Water/dry sample A B C = B – A D E = C- DF %= (E/D) * 100 LL=F COMPARE results among GROUP in class
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Distilled water until the soil is at a consistency where it can be rolled without sticking to the hands. Plastic limit The plastic limit (PL) is the water content where soil starts to exhibit plastic behavior. A thread of soil is at its plastic limit when it is rolled to a diameter of 3 mm or begins to crumble. To improve consistency, a 3 mm diameter rod is often used to gauge the thickness of the thread when conducting the test. around20 g
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If you don’t get it!! Then, weight the crumbles
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Repeat all steps at least 3 times until get the sample at least 60 grams In this experiment, let 1 student do 1 sample of 20 g. Thus, we will have 60 g sample for Plastic limit calculation
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Weight of wet sample and bag Weight of day sample (from baking) Weight sample – dry sample Water/dry sample A B C = B – A D E = C- DF %= (E/D) * 100 PL=F
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Solid behaviorPlastic behaviorLiquid behavior Water content 0 Dry soil Wet soil Liquid limitPlastic limit Max Part 1 Then, add more water in bowl until Clay merge together ~0.5” wide STOP!! Mix water with clay Clay didn’t merge After 25 taps Part 2 Roll more to dry clay until Can roll clay into ½ diameter size Mix too much water with clay Cannot roll it anymore (break a part) STOP!! Liquid limit determination Plastic limit determination SUMMARY of LL and PL concepts
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Hint: We have clay and sand samples
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