Engineering Homework Help

• TEXTBOOK : Liquid Limit : Lab 6 in 8th, 9th edition, Plastic Limit: Lab 8 in 9th, Lab 7 in 8th

• Objective : To determine the liquid and plastic limits of the given soil sample
• Atterberg Limit : Basic measure of the critical water contents of a fine-grained soil, such as its shrinkage limit, plastic limit and liquid limit.
• Liquid Limit(LL) :
  • The moisture content, in percent, at which the cohesive soil will pass from a liquid state to a plastic state.
  • The moisture content at which it takes 25 drops of the cup to cause the groove to close over a distance of 13.5 mm (0.53 in)

• Plastic Limit(PL) :
  • The moisture content, in percent, at which the cohesive soil will pass from a plastic state to a semisolid state.
  • The moisture content at which a thread of soil will just crumble when rolled to a diameter of 1/8 in (3.2mm)

You will find more information with Virtual Labs of Atterberg Limits http://smfe-iiith.vlabs.ac.in/exp5/Introduction.html?domain=Civil%20Engineering&lab=Soil%20Mechanics%20Lab

Missouri University, (2012, Jun 2). Atterberg Limit Tests(LL and PL) [Video]. Youtube

Submit a lab report based on the video above and using experimental data given in Table 4-1 and 4-2.

Table 4-1. Liquid Limit Test Data – Percussion Cup Method

Item	No 1	No 2	No 3
Mass of can M1 (g)	50.94	51.55	51.78
Mass of can + Moist soil M2(g)	66.74	67.56	66.90
Mass of can + dry soil M3(g)	62.99	63.53	62.94
Moisture Content $w\left(\%\right)=\frac{M_2-M_3}{M_3-M_1}\times 100$	?	?	?
Number of Blows(N)	28	21	15

Table 4-2. Plastic Limit Test Data

Item	No 1	No 2
Mass of can M1(g)	51.80	50.90
Mass of can + moist soil, M2(g)	67.50	65.50
Mass of can + dry soil, M3(g)	65.04	63.26
$PL=\frac{M_2-M_3}{M_3-M_1}\times 100$	?	?

Lab Report should

1. Write down the procedures described in the video(Missouri University, 2012).
2. Present data tables for both tests, the plot of moisture content vs. number of blows for LL results reported in Table 4-1
3. Find the liquid limit(LL) obtained from the plot and the plastic limit(PL) of a soil
4. Report a PI(Plastic Index) and LI(Liquid Index) assuming w (natural moisture content) is 20
5. Estimate the LL using Eq (6.3) in the textbook with N-value between 20 and 30 in the results and compare the estimated LL with LL obtained from the graph.
6. Follow lab report guidelines under Modules/Lab Information on Canvas.

$LL=w_N\left(\%\right)\times {\left(\frac{N}{25}\right)}^{0.121}\left(Eq6.3\right)$where wN is the moisture content at N number of blows