A 0.3 m well has a 25 m long screen that covers the entire depth of an aquifer. The aquifer medium has an effective grain size of 1.5 mm. The well is pumped at a rate of 0.2m³/s. Assess the validity of Darcy's law near the well. Assume, porosity = 0.25(Dynamic viscosity of water at 20°C is 1.005*10-3 Ns/m2)

Darcy's Law is an equation that describes the flow of a fluid through a porous medium. It is valid…

Answered: A 0.3 m well has a 25 m long screen…

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 7.13P

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2. A confined aquifer is recharged by a continuous supply of water from the certain source. The average thickness of the aquifer was determined to be 25 m and the average width is 4 km. The hydraulic conductivity of the aquifer was obtained at 40 m/day and its void ratio is 0.3333. The piezometer heads in two wells 1.325 km apart are 65 meters and 60 meters from a common reference datum. Determine the rate of flow in cubic meters per day. Determine: •compute the rate of flow through the aquifer in m3/day •compute the seepage velocity in m/day •compute the time of travel from the head of the aquifer to a point 8 km downstream in days
Given the following: H1 = 1.5 m H2 = 3.0 m H3 = 2.0 m K1 = 0.001 cm/sec K2 = 0.032 cm/sec K3 = 0.000041 cm/sec 1. Find the effective average permeability of the deposit in the horizontal direction. (in cm/s) 2. Find the effective average permeability of the deposit in the vertical direction. (in cm/s) 3. What is the ratio of the equivalent hydraulic conductivity?
A 30 cm well penetrates 45 m below the static water table. After a long period of pumping at a rate of 1200 lpm, the drawdown in the wells 20 m and 45 m from the pumped well is found to be 3.8 and 2.4 m respectively. Determine the transmissivity (-K*aquifer thickness) of the aquifer. What is the drawdown in the pumped well? [Hint: Use water table depth as aquifer thickness in the case of unconfined aquifer]
A field sample of an aquifer is packed in a test cylinder. The cylinder has a length of 120 cm and a diameter of 12 cm. The field sample with a porosity of 0.24 is tested under a constant head difference with water at 10°C. If the estimated hydraulic conductivity of the sample is 40 m/day and the hydraulic gradient is 1.5, calculate the average flow velocity (pore velocity). Ply Sand column Datum plane O a. u = 166.63 m/d O b. u = 250.00 m/d O c.u = 200.00 m/d O d. u = 48.00 m/d
A confined aquifer shown has hydraulic conductivity of 52 m/day with void ratio of 0.282. The average thickness is 30 m and the average width is 4 km. el = 85 m el = 55 m 30 m aquifer 1400 m Determine the nearest value of the time of travel from the head of aquifer to a point 5.2 km downstream in days (in a whole day).
Qs. The difference between the free water levels in two wells 48 m part in an aquifer is 0.6m. It took an interval of 8 hours between detecting the traces of a tracer material at the two wells in succession. The porosity of the aquifer is 25%. The coefficient of permeability of the aquifer is_______ cm/sec.please dont solve wrong
1. A confined aquifer is recharged by a continuous supply of water from the certain source. The average thickness of the aquifer was determined to be 18 m and the average width is 8 km. The hydraulic conductivity of the aquifer was obtained at 60 m/day and its void ratio is 0.1586. The piezometer heads in two wells 2,145m apart are 128 meters and 188 meters from a common reference datum. Determine: •compute the rate of flow through the aquifer in m3/day •compute the seepage velocity in m/day •compute the time of travel from the head of the aquifer to a point 8 km downstream in days
A well penetrates an unconfined aquifer, with undisturbed water level (ho) equal to 21m. After pumping the well at a constant rate of Q = 0.07 m/s, the steady-state drawdown at distances of 45 m and 110 m from the well are 3 m and 1 m. respectively. Assume the void ratio as 0.2. Compute the hydraulic conductivity of the aquifer. 215.0 m/day what is the porosity 0.16 find the darcy velocity in m/day 69.4 m/day
An artesian aquifer 25-m thick has a porosity of 17% and bulk modulus of compression 2400 kg/ cm?. Estimate the storage coefficient of the aquifer. What fraction of this is attributable to the expansibility of water ? Bulk modulus of elasticity of water = 2.14 × 104 kg/cm². Ans: (0.00106, 1.87%)
For a falling-head permeability test, the following values are given: Length of specimen = 200 mm Area of soil specimen = 1000 mm^2 Area of standpipe = 40 mm^2 Head difference at time t = 0 = 500 mm Head difference at timt t = 3 minutes = 300 mm Determine the hydraulic conductivity of the soil in ×10−4cmsec Please answer this asap. For upvote. Thank you very much
Problems An aquifer of 20m average thickness is overlain by an impermeable layer of 30m thickness. A test well of 0.5m diameter and two observation wells at a distance of 10m and 60m from the test well are drilled through the aquifer. After pumping at a rate of 0.1 m³/s for a long time, the following draw downs are stabilized in these wells. First observation well, 4m, second observation well, 3m. Show the arrangement in a diagram. Determine the coefficient of Permeability and the drawdown in the test well.
Please explain part 1 (ii) of the question given. 1) i) A 6 inch diameter well that fully penetrates a 40ft thick open aquifer is pumped at a rate of 100 gpm. The drawdown in the well is 22ft when a steady water level is established. The drawdown in a well 152ft distant is 12ft. Estimate the coefficient of permeabiliity of the soil deposit. Answer of permeability is K= 9.88 x10-4 ft/sec. ii) Discuss the validity of the answer obtained in 1( i ) and suggest how would you improve the test data obtained to produce a better value of k. Why?

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