Concept explainers
Find the hydraulic uplift force at the base of the hydraulic structure per meter length.
Answer to Problem 8.5P
The hydraulic uplift force at the base of the hydraulic structure per meter length is
Explanation of Solution
Given information:
The hydraulic conductivity of the permeable soil layer k is
The head difference between the upstream and downstream H is 10 m.
The height of the water level
The depth of permeable layer up to the tip of the hydraulic structure D is 1.67 m.
The depth of permeable layer
Calculation:
Draw the free body diagram of the flow net for the given values as in Figure 1.
Determine the head loss for each drop using the relation.
Here,
Refer Figure 1.
The number of potential drop
Substitute 10 m for H and 12 for
Determine the pressure head at D using the relation.
Here, flow dis is the flow net distance.
Substitute 10 m for H, 3.34 m for
Determine the pressure head at E using the relation.
Substitute 10 m for H, 3.34 m for
Determine the pressure head at F using the relation.
Substitute 10 m for H, 1.67 m for D, 3.5 m for flow dis, and 0.833 for
Determine the pressure head at G using the relation.
Substitute 10 m for H, 1.67 m for D, 8.5 m for flow dis, and 0.833 for
Determine the pressure head at H using the relation.
Substitute 10 m for H, 3.34 m for
Determine the pressure head at I using the relation.
Substitute 10 m for H, 3.34 m for
Determine the hydraulic uplift force at the base of the hydraulic structure per meter length using the relation.
Here,
Take unit weight of water
Substitute
Draw the pressure head diagram as in Figure 2.
Therefore, the hydraulic uplift force at the base of the hydraulic structure per meter length is
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Chapter 8 Solutions
Principles of Geotechnical Engineering (MindTap Course List)
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