A sand deposit of 12 m thick overlies a clay layer. The water table is 3 m below the ground surface. In a field permeability pump-out test, the water is pumped out at a rate of 540 liters per minute when steady state conditions are reached. Two observation wells are located at 18 m and 36 m from the Centre of the test well. The depths of the drawdown curve are 1.8 m and 1.5 m respectively for these two wells. Determine the coefficient of permeability

A sand deposit of 12 m thick overlies a clay layer. The water table is 3 m below the ground surface. In a field permeability pump-out test, the water is pumped out at a rate of 540 liters per minute when steady state conditions are reached. Two observation wells are located at 18 m and 36 m from the Centre of the test well. The depths of the drawdown curve are 1.8 m and 1.5 m respectively for these two wells. Determine the coefficient of permeability

Fundamentals of Geotechnical Engineering (MindTap Course List)

5th Edition

ISBN:9781305635180

Author:Braja M. Das, Nagaratnam Sivakugan

Publisher:Braja M. Das, Nagaratnam Sivakugan

Chapter6: Hydraulic Conductivity

Section: Chapter Questions

Problem 6.15P

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A sand deposit of 12 m thick overlies a clay layer. The water table is 3 m below the ground surface. In a field permeability pump-out test, the water is pumped out at a rate of 540 liters per minute when steady state conditions are reached. Two observation wells are located at 18 m and 36 m from the Centre of the test well. The depths of the drawdown curve are 1.8 m and 1.5 m respectively for these two wells. Determine the coefficient of permeability. Include FBD.
A sand deposit of 12 m thick overlies a clay layer. The water table is 3 m below the ground surface. In a field permeability pump-out test, the water is pumped out at a rate of 540 litres per minute when steady state conditions are reached. Two observation wells are located at 18 m and 36 m from the centre of the test well. The depths of the drawdown curve are 1.8 m and 1.5 m respectively for these two wells. Determine the coefficient of permeability. a. 625 X 10^-2 b. 2.15 x 10^-2 c. 4.5 x 10^-1 d. 1.6 X 10^-1
An artesian aquifer 5 m thick with a piezometric surface 65 m above the bottom confining layer is being pumped by a fully penetrating well. The aquifer is a mixture of sand and gravel. A steady-state drawdown of 7 m ・ s−1 is observed at a nonpumping well located 10 m away. If the pumping rate is 0.020 m3 ・ s−1, how far away is a second nonpumping well that has an observed drawdown of 2 m?
A soil profile consists of a clay layer of 10 m thick between a permeable sand layer above and an impermeable rock layer below, the water table being in the sand layer. Before the construction of a reservoir raft foundation, piezometers were installed in the clay layer.The whole process of filling the reservoir may be approximated to applying rapidly a single pressure increment of 100 kN/m2 uniformly throughout the clay layer. One year after filling the reservoir, the settlement was 20 cm and the piezometers indicated the distribution of excess pore pressure as shown in the figure below. Estimate the final settlement and the time to complete 90 % of primary consolidation.
A 30 cm well completely penetrates an unconfined aquifer of saturated depth 40 m. After a long period of pumping at a steady rate of 1500 lpm, the drawdown in two observation wells 25 and 75 m from the pumping well were found to be 3.5 m and 2.0 m respectively. a.) Determine the transmissivity (m^2/s) of the aquifer. b.) What is the drawdown (m) at the pumping well?
a 30 cm well penetrates an unconfined aquifer of saturated depth 25m. When a discharged of 2100 lpm was being pumped for a long time, observation wells at radial distances of 30 and 90 m indicated drawdown of 5 and 4 m respectively. estimate the coefficient of permeability of the aquifer and the drawdown at drawdown at pumping well.
The discharge from a fully penetrating well operating under steady state in a confinedaquifer of 35 m thickness is 2000 lpm. Values of drawdown at two observation wells 12 and 120 m away from the well are 3.0 and 0.30 m respectively. Determine the permeability of the aquifer.
An unconfined aquifer is known to be 32 m thick below the water table. A constant discharge of 2 cubic metres per minute is pumped out of the aquifer through a tubewell till the water level in the tubewell becomes steady. Two observation wells at distances of 15 m and 70 m from the tubewell show falls of 3 m and 0.7 m respectively from their static water levels. Find the permeability in mm/s of the aquifer. a.3.28 x 10^-1 b.4.68 x 10^-1 c.2.58 x 10^-1 d.1.18 x 10^-1
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.
A well penetrates an unconfined aquifer. Prior to pumping the water level(head) is ho = 25m after a long period of pumping at a constant rate of 0.05 m^3/s the drawdowns at distances of 50m and 150 m from the well were observed to be 3 m and 1.2 m respectively. Compute the hydraulic conductivity of the aquifer and the radius of influence of the pumping well. What type of deposit is the aquifer material?
An unconfined aquifer exists where a buried river channel cut into underlying impermeable bedrock. The figure below shows the orientation and pertinent dimensions. The flow rate at the pumping well is 250 gpm, and its radius of influence is 1000 ft. The hydraulic conductivity of the aquifer is 15 ft/d, and the initial saturated thickness is 120 ft. Find the drawdown at the observation well under equilibrium conditions.
An unconfined aquifer is known to be 32 m thick below the water table. A constant discharge of 2 cubic meters per minute is pumped out of the aquifer through a tube well till the water level in the tube well becomes steady. Two observation wells at distances of 15 m and 70 m from the tube well show falls of 3 m and 0.7 m respectively from their static water levels. Find the permeability of the aquifer (mm/s).