A river bed consists of a layer of sand 8.25 m thick overlying impermeable rock; the depth of water is 2.50 m. A long cofferdam 5.50 m wide is formed by driving two lines of sheet piling to a depth of 6.00 m below the level of the river bed, and excavation to a depth of 2.00 m below bed level is carried out within the cofferdam. The water level within the cofferdam is kept at excavation level by pumping. If the flow of water into the cofferdam is 10.25 m'/h per unit length, a. Draw the flow net for the seepage flow -5.50m b. what is the coefficient of permeability of the sand? Sheet piling c. what is the hydraulic gradient immediately below the excavated surface? d. What is the lateral earth pressure at points A, B,. 2.50m Evi 2.00m vel Datum y=115 pcf =30° 6.00m 2.25m Natteale

A river bed consists of a layer of sand 8.25 m thick overlying impermeable rock; the depth of water is 2.50 m. A long cofferdam 5.50 m wide is formed by driving two lines of sheet piling to a depth of 6.00 m below the level of the river bed, and excavation to a depth of 2.00 m below bed level is carried out within the cofferdam. The water level within the cofferdam is kept at excavation level by pumping. If the flow of water into the cofferdam is 10.25 m'/h per unit length, a. Draw the flow net for the seepage flow -5.50m b. what is the coefficient of permeability of the sand? Sheet piling c. what is the hydraulic gradient immediately below the excavated surface? d. What is the lateral earth pressure at points A, B,. 2.50m Evi 2.00m vel Datum y=115 pcf =30° 6.00m 2.25m Natteale

Fundamentals of Geotechnical Engineering (MindTap Course List)

5th Edition

ISBN:9781305635180

Author:Braja M. Das, Nagaratnam Sivakugan

Publisher:Braja M. Das, Nagaratnam Sivakugan

Chapter11: Ground Improvement

Section: Chapter Questions

Problem 11.10CTP

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