Soil and weathering lab Niti Mankhemthong 15/10/10

-Roundness? - Grain size? -Sorting? Channel flow vs flow velocity vs sediment load & clasts

Speed water flow and Size???

122

Coarse-grained textures Texture Grain Sorting Grain Rounding

Grain Size

Sorting or Graduation

Grain Roundness or Particle shape

Look at a descriptive handout

Observational data in terms of fluid velocity and grain size:

~ 100 g Weight the dry clay (sieve no. 45 (~0.33 m)) Mixed with little water (2 spoon water ) 1 cm height

TAP!! 25 TIMES If you do not get Weight the final wet samples Add ½ spoon water each turn

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

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

If you don’t get it!! Then, weight the crumbles

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

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

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

Hint: We have clay and sand samples