Geotechnical Engineering

Question 1

Think of inverses for soil sizes
ie 40% larger than .45 mm so…

Answer 1

60% is smaller than .45 mm
D_60=.45 mm

Question 2

Remaining unsettled in a hydrometer test is comprised of

Answer 2

Clay

Question 3

To find unit weight given S, ω, G_s

Answer 3

Use saturated unit weight BUT use ( Se) in numerator

Question 4

Shear stress on failure surface given

σ_1, σ_3, θ

Answer 4

τ = [(σ_1 + σ_3)/2] x sin(180 - 2θ)

Question 5

σ_1 when given;

σ_3, φ, c

Answer 5

σ_1 = σ_3tan^2(45+φ/2) +2c*tan(45+φ/2)

Question 6

φ given

Κ_Ρ - Rankine value

Answer 6

2arctan(sqrt(K_P))

Question 7

q_gross = ΣW/A

Question 8

vertical effective stress q

Answer 8

= γD_f

Question 9

q_net =

Answer 9

q_u - q

Question 10

FS with respect to q

Answer 10

= q_net / q_all

Question 11

Strip footing used for

Answer 11

Supporting a row of columns or a wall

Question 12

Criteria for loose footing

Answer 12

Length/width = 10

Question 13

What foundation supports larger loads

Answer 13

End bearing cum friction piles

Question 14

Type of settlement that causes problems for doors and windows

Answer 14

Differential

Question 15

All types of settlement cause problems for the main entrance if the settler is large

Answer 15

True

Question 16

H_A

Answer 16

H_total - (# of equipotential lines on one side)*(H/(all equipotential lines +1))

Question 17

Weight per unit

Answer 17

W = A*γ

Multiply by radians if specific section

Question 18

M_mob

Answer 18

W_Mxcos(β)

X is the x_c Eq from concurrent forces

Question 19

Aspect of Portland cement that contributes to soil stabilization

Answer 19

Cement hydration

Question 20

What aspect of asphalt in soil contributes to soil stabilization

Answer 20

Bonding effect of asphalt

Question 21

Effective unit weight of a fully submerged soil sample will be

Answer 21

Less than saturated soil sample

Question 22

Density of water in g/cm^3

Answer 22

1.0

Question 23

Round down for effective stress

Answer 23

81.2 -> 80

Question 24

Red block denotes A

Answer 24

NOT THE ARROW

Question 25

REMEMBER degree of saturation multiplies top e in saturated unit weight

Answer 25

If S not given, sub in Eq

Question 26

Hydraulic gradient

Answer 26

(γ_sat - y_w)/y_w

Question 27

Slope failure W_m

Answer 27

y_sat - y_w * area

Question 28

Effective weigh sample compared to saturated unit weight after full submersion

Answer 28

Eff < sat

Question 29

Trapezoidal footing

Answer 29

For two columns close together

Question 30

The higher H is in slope stability

Answer 30

The lower the FS is

Question 31

In slope stability analysis, using the method of slices, which of the following assumptions is made?

Answer 31

The forces on the sides of each slice are assumed to be horizontal

Question 32

What limes can be used for soil stabilization

Answer 32

Calcium oxide Calcium carbonate