Principles of Geotechnical Engineering (MindTap Course List)
9th Edition
ISBN: 9781305970939
Author: Braja M. Das, Khaled Sobhan
Publisher: Cengage Learning
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Question
Chapter 7, Problem 7.4P
(a)
To determine
The rate of seepage per unit length of the dam.
(b)
To determine
The seepage velocity.
(c)
To determine
The quantity of seepage per day.
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Students have asked these similar questions
Q.1. The figure below shows the flow net for seepage under a concrete dam. The is silty sand
with coefficient of permeability of 4X104 cm/sec, a void ratio of 0.6 and specific gravity of 2.7.
The height of water upstream is H=( 6+)
(a) Determine the flow rate under the dam in m/day per m length of the dam.
(b) Determine the water pressure distribution at the base of the dam. (Select 3 points under the
base. Comment on your results.
m (where X is your group number).
(c) From (b), calculate the resultant uplift force and its location from the upstream face of the
dam. Also, calculate the weight of the dam to prevent uplift using a factor of safety of 5.
(d) What is the factor of safety against piping? Is the dam safe?
(e) Calculate the total vertical overburden stress, pore water pressure and the effective vertical
overburden stress at Points A and B. Comment on your results.
H
17.5 m
1.25 m
x B
4 m
Impervious clay
9) A well is located in a confined aquifer near the intersection of a constant head and
impervious boundary.
a) Estimate the steady state drawdown in the well for Q=2 ft³ s, rw = 1 ft,
distance from the well to stream= 300ft and distance from well to
impervious boundary= 150 ft. T = 0.14ft²/s
b)
Estimate the steady state drawdown at point P located midway between
the well and the steam.
The angle between the stream and the impervious boundary is 90°
Nf : 5
Nd=16
25 m
Question 4
Seepage take place beneath a concrete dam as shown in Figure 2. The soil beneath the dam is a
fine silty sand with hydraulic conductivity of 4.2 x 10“cm/s and saturated unit weight of 19.5
kN/m³.
6 m
1.75 m:
1) Find the rate of seepage beneath the dam in m³/day/m
2) If a standpipe piezometer is installed at the tip of the sheet pile, how high will the water
rise?
Impervious stratum
Chapter 7 Solutions
Principles of Geotechnical Engineering (MindTap Course List)
Ch. 7 - Prob. 7.1PCh. 7 - Prob. 7.2PCh. 7 - Prob. 7.3PCh. 7 - Prob. 7.4PCh. 7 - Prob. 7.5PCh. 7 - Prob. 7.6PCh. 7 - Prob. 7.7PCh. 7 - Prob. 7.8PCh. 7 - Prob. 7.9PCh. 7 - Prob. 7.10P
Ch. 7 - Prob. 7.11PCh. 7 - Prob. 7.12PCh. 7 - Prob. 7.13PCh. 7 - Prob. 7.14PCh. 7 - Prob. 7.15PCh. 7 - Prob. 7.16PCh. 7 - Prob. 7.17PCh. 7 - Prob. 7.18PCh. 7 - Prob. 7.19PCh. 7 - Prob. 7.20PCh. 7 - Prob. 7.21PCh. 7 - Refer to Figure 7.24. The following data were...Ch. 7 - Prob. 7.23PCh. 7 - Prob. 7.1CTP
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Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, civil-engineering and related others by exploring similar questions and additional content below.Similar questions
- Refer to Figure 7.24. The following data were collected during the field permeability measurement of a confined aquifer using a pumping test. Determine the hydraulic conductivity of the permeable layer. Use Eq. (7.49). Thickness of the aquifer, H = 4.5 m Piezometric level and radial distance of the first observation well: h1 = 2.9 m; r1 = 17.8 m Piezometric level and radial distance of the second observation well: h2 = 1.8 m; r2 = 8.1 m Rate of discharge from pumping, q = 0.5 m3/minarrow_forwardRefer to the cross section of the earth dam shown below. Calculate the rate of seepage through the dam (q in m/min/m) using Schaffernak's and Casagrande's solutions. +7 m→| 3 m G.W.T. 1 32 m 2.0 2.0 Impermeable layerarrow_forwardReferring to Figure Q3, calculate the following quantities: a. Elevation head, total head, and pressure head at point M on Figure Q3. b. The quantity of water seeping through the dam of Figure Q3 per day. The hydraulic conductivity of the soil is 10-8 Boundary equipotentials Na = 9 N = 3 Boundary flowlines %3D 10 m %3D 12 m 6 m M A (11 m7 m 1 m 2 m Fig. Q3: Earth Damarrow_forward
- A drainage pipe beneath a dam has clogged with sand whose coefficient ofpermeability is found to be 8.0 meters per day. The average difference inheadwater and tailwater elevation is 21.6 meters and it has been observed thatthere is a flow of 162 liters per day through the pipe. The pipe is 96.3 meterslong and has a cross-section area of 180 sq. cm. What length of the pipe isfilled with sand?arrow_forward#18 A non isotropic soil supporting the dam as shown in the figure. The flow net has 4 flow channels and 20 equipotential drops. Coefficient of permeability of soil. Vertical coefficient of permeability: Kv = 0.002 m/day Horizontal coefficient of permeability: Kx = 0.018 m/day 12m 4marrow_forwardAn earth dam is shown in (Figure 1). Determine the seepage rate, q, in m³/day/m Length using Schaffernak's method. Given: a₁ cm/sec. 35, a₁ = 40, L₁= 5m, H = 7m, H₁ = 10m, and k = 3 × 10-4 +44 Water level = Impervious base H₁arrow_forward
- Q2) For the concrete dam in Fig. 2, calculate the 1) seepage quantity in cm³/sec, and 2) pore water pressure (u) in the points 1 to 7 at the bottom of the dam. (yw = 10 kN/m³). the Nd. 1.5 m 10 m 3 1 .} 4 (k = 10-³ cm/sec) } 1 1 1 24 m " R I 1 1 Figure 2.arrow_forward5.4 The figure shows the cross-section of a levee that is 500 m long and is underlain by a 2-m-thick permeable sand layer. It was observed that the quantity of water flowing through the sand layer into the collection ditch is 250 m³/day. What is the hydraulic conductivity of the sand layer. Ans. k = 3.125 m/day Elv. 160 m Levee Elv. 150 m 2 m Ditch 125 m Impervious Sandarrow_forwardSituation 2: 4. 5. For the given figure, r₁ = 30 m r₂ = 10 m H = 20 m t = 15 m Q = 13 L/s h = 13.6 m h₁ = 17.6 m h₂ = 16.3 m d = 0.6 mø draw down H t d ₂1 C Find the permeability of the aquifer in m/s. Compute for the transmissivity of the impermeable layer in m²/s. h₂ 5 h₁ -observation wells -impermeable Confined layer Aquiferarrow_forward
- A pump well is dug through a confined aquifer having a thickness of 32 meters. The piezometric surface of the aquifer is 18 meters measured from the top impermeable layer. The first observation well is 75 feet directly west of the pump well and the second observation well is 75 feet directly north of the first observation well. Determine the hydraulic conductivity of the aquifer if it supplies a discharge of 10 liters per second and the drawdown of the observation wells are 13 feet and 23 feet.arrow_forwardQ3 Figure Q3 shows a flow net for flow through a weir, the base of which is 2m below the ground surface, in a permeable soil layer. Given that the coefficient of permeability =k = 5×10-³ cm/sec, determine the following: - 14 m 7 m 8 m 2 m 10 m kx = k, = k Impermeable laye Figure Q3 a) Total head (m) at point a, b, c, d, e, and f. b) Uplift pressure (or water pressure, kPa) at point a, b, c, d, e, and f. c) The total rate of seepage per unit length through the permeable layer. d) The approximate average hydraulic gradient at point f.arrow_forward8.12 An earth dam section is shown in Figure 8.28. Determine the rate of seepage through the carth dam using Pavlovsky's solution. Use k- 4x 10 mm/s. Critical Thinking Problem 8.C.I Refer to Problem 8.12. Given Ak = 4x 10 m/min and k =1X 10 m/min.arrow_forward
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