Question

problem 8.3 pls thank you

Problems 179 8.2 In Problem 8.1, what is the rate of upward seepage of water? Given: hydraulic conduc- tivity of soil, k- 0.13 em/sec, and area of tank 052 m2. Give your answer in m'min. 8.3 through 8.7 Refer to Figure 8.16. Calculate σ. ", and σ' at A, B, C and D for the following cases and plot the variations with depth. (Note: e void ratio. mois- ture content, G, s ific gravity of soil solids. γ.-dry unit weight, and γ- saturated unit weight.) Hy Layer l : .. Layer แ Hi Dry sand SandClay Rock Figure 8.16 Details of soil layer Problem Hi 1.5 m H: 183 m H 244 m 8.3

Answer 1

We have

Total stress = Effective stress + Pores water pressure

q = q'+ u

=> q' = q - u

where q = Y_sxh_s

u = Y_wxh_w

Y_s = unit wt of soil

h_s = height of soil

Y_w = unit wt of water = 9.81 kN/m³

h_w = ht of water table

At A

q = 0 , u = 0 , q' =0

At B

q = 17.6x1.5 = 26.4 kN/m²

u = 0

q' = 26.4 kN/m²

At C

q = 17.6x1.5 + 18.87x1.83

= 60.93 kN/m²

u = 9.81x1.83 = 17.95 kN/m²

q' = 60.93 - 17.95 = 42.98 kN/m²

At D

q = 17.5x1.5 + 18.87x1.83 + 19.65x2.44

= 108.72 kN/m²

u = 9.81x(1.83+2.44)

= 41.84 kN/m²

q' = 108.72 - 41.84

= 66.88 kN/m²
0 1.5 26.4 0 26.4 1.83 60.93 42.98 17.95 0: 2.44 66.88 108.72 Pore pressure (u) Effective stress(q) Total stress(q)