Assignment 1
Deadline 11/02/2022
Please type the answers
1. The sieve analysis and plasticity data of two soils are given as follows [30 marks]
Soil #1
Soil #2
Sieve Size
Percentage Passing
Percentage Passing
No. 4
98
100
No. 10
91
93
No. 20
65
89
No. 40
39
87
No. 100
9
77
No. 200
6
61
Atterberg Limits Water Content (%)
Water Content (%)
LL
-
20
PL
-
15
Plot the particle size distribution curves of these soils, and classify them according to the
Unified Soil Classification System. (The particle size distribution curves can be drawn either
by hand or by computer software.)
2. A sieve analysis on a sample of initial total mass 411 g gave the following results: [30
marks]
Sieve size, mm
6.3 1.2
Mass retained, g 0
60
0.3
0.063
126 92
A sedimentation test on the 121 g of soil collected in the pan at the base of the sieve stack
gave:
Size, μm
<2 2-10 10-60
% of pan sample 33
24
43
Plot the particle size distribution curves of these soils, and classify them according to the
Unified Soil Classification System. (The particle size distribution curves can be drawn either
by hand or by computer software.)
3. A soil has an in-situ (in-place) voids ratio e =1.87, water content w = 60%, and specific
gravity Gs = 2.75. What are the bulk unit weight γ and the degree of saturation Sr? [10
marks]
4. A sand with Gs = 2.66 and e = 0.60 is completely dry. It then becomes wetted by a rising
groundwater table. Compute the total unit weight (kN/m3) under the following conditions:
[30 marks]
a) When the sand is completely dry (Sr = 0%)
b) When Sr = 40%
c) When Sr = 100%