(b) Seepage takes place beneath a concrete dam as shown in Figure Q3. The soilbeneath the dam is fine silty sand with hydraulic conductivity (permeability) of4.2 x 10- cm/sec and saturated unit weight of 19.5 kN/m³.i. Calculate the rate of seepage beneath the dam in m/day/m.ii. If a standpipe (piezometer) is installed at point A, how high will the water rise?i. Calculate the pore water pressure at point A.R1.75mImpervious stratumFigure Q3

(a) The flow rate beneath the dam is calculated as, q=kHNfNd=4.2×10-4 cm/sec×10-2×24×3600 m/day1…

Answered: (b) Seepage takes place beneath a…

Principles of Geotechnical Engineering (MindTap Course List)

9th Edition

ISBN:9781305970939

Author:Braja M. Das, Khaled Sobhan

Publisher:Braja M. Das, Khaled Sobhan

Chapter7: Permeability

Section: Chapter Questions

Problem 7.4P

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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
An earth dam of homogeneous section with a horizontal filter is shown in Fig. below. If the coefficient of permeability of the soil is 3 x 10³ mm/s, Draw seepage line and find the quantity of seepage per unit length of the dam. Seepag 30 m 8m 200 m K 45 m
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
Refer 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 layer
For a homogeneous earth dam 32 m high and 2 m free board, a flow net was constructed with four flow channels. The number of potential drops was 20. The dam has a horizontal filter at the base near the toe. The coefficient of permeability of the soil was 9 × 10^–2 mm/s. Determine the anticipated seepage in m^3/s, if the length of the dam is 100 metres. a.0.98 b.0.120 c.0.054 d.0.045
Refer to the cross section of the earth dam shown in the figure. Calculate the rate of seepage through the dam (q in m3/ min / m) using L. Casagrande's method. K 5 m 1V: 2H 30 m 1V: 2H 25 m k = 3 x 10-4 m/min Impermeable layer Select the correct response: 5.91 x 103 m/min/m 2.37 x 103 m3/min/m 11.4x 104 m/min/m 29.5 x 104 m3/min/m
SITUATION 4 The soil under a dam has three layers with different coeffident of permeability. Determine the following: (a) Calculate the equivalent hydraulic conductivity in am/sec. (b) Compute the Transmissibility of the soil when the water table is at the ground surface, in sq.cm/ sec (Note: Transmissibility= k x distance) (c) Determine the seepage velocity of water moving through soil if it has a void ratio of 0.60 and a hydraulic gradient of 0.0018 in cm/hr. Illustration for Situation 4 KI = 0.000 I0 cm/sec at 3m K2= 0.032 cm/sec at 4m K3= 0.000041 cm/sec at Gm
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.
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A clay sample is 2.5 cm high and has a diameter of 6.5 cm. It is placed in an oedometer with a variable- head permeameter. The water percolation through the sample is measured in a standpipe whose inner diameter is 1.7 mm. The tube is graduated in centimeters from the top to the bottom. The top graduation is zero and is located 35 cm above the base of the oedometer. The overflow in the oedometer is 3 cmabove its base. At the start of the test, the water level in the tube is at zero; 6 mins and 35 sees later, the water level has dropped to graduation 2. What is the coefficient of permeability of the clay in cm/s?
#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 4m
12 Determine the quantity of seepage under the dam cross section shown in m3/s/m if the soil has hydraulic conductivity, k=0.0001 meter cube per second. Note the numbers in the figure from left to right are:2.0m, 1.8m, 2.4m and 8.0 m, respectively. 2.00m 8.00 m 1.80 m Datum 12.40m 777 Enter your answer

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