qatar university college of engineering department of civil and arch e

Question

Qatar University
College of Engineering
Department of Civil & Arch. Engineering
1. Direct shear box test results for clayey sand specimens tested at three different normal stresses
are shown in Table 1.
a. Plot the shear stress-shear displacement relationship and determine the peak shear strength at
each normal stress. At which value of shear displacement would the peak shear strength be
mobilized?
b. Draw the failure envelope for the peak shear strength. Use the same scale for the x and y axes.
e. Determine the shear strength parameters and write the equation that can be used to estimate
the peak shear strength (5,) of the tested soil.
Table 1. Test results for soil tested in direct shear apparatus
Normal Stress (G)-42 kPa
Time, see (t)
0
30
60
90
120
150
Proving ring reading
(Div.)
0
15.9
27.4
37.1
45
52
Foundation Engineering I (CVEN 330)
Assignment No. 1 (Sep. 21, 2023)
180
210
240
270
300
330
360
390
420
450
480
510
540
Use the following to process the data:
57.4
61.8
65.2
68.8
69.7
68
61.8
15.9
G-78 kPa
Proving ring reading
(Div.)
0
31.8
51.2
65
• Area of shear box-6×6 cm² -0.0036 m²
Shear rate=0.01 mm/sec
• Proving ring constant-0.00204 kN/div
•
74.1
85.4
93.2
104.8
108.7
109.4
108.5
98.8
31.8
G-130 kPa
Proving ring reading
(Div.)
0
45.9
70.6
91.75
Shear Displacement, &-Shear rate time
Shear Force, T-Proving ring constant Proving ring reading
Shear Stress, T-T/cross-section area of shear box
107.65
120
129.5
138.7
146.1
151.2
157.95
162.35
166.2
169.4
171.9
174
175.5
173.5
169.4
Hint: You may use the following equations to process the data of the table, and show
detailed calculations in your solution.