Question

From a flow-net, which of the following information can be obtained?

A. Rate of flow 
B. Pore water pressure 
C. Exit gradient 
D. Permeability 
Choose the most appropriate answer from the options given below:

• A. A, B, C and D
• B. A, B and C only
• C. B, C and D only
• D. A only

Hint:

A flow-net helps in analyzing seepage quantities, pore pressures, and exit gradients, but not soil properties like permeability.

Answer 1

The Correct Option is B

Step 1: Defining Flow-Net.
A flow-net visually depicts the flow of groundwater through soil. It is constructed using flow lines and equipotential lines, providing a method to analyze seepage without complex differential equation solutions.

Step 2: Data Derivable from Flow-Net.
- (A) Flow Rate: Can be calculated based on the number of flow channels and potential drops.
- (B) Pore Water Pressure: Can be estimated at any specific location by referencing the equipotential lines.
- (C) Exit Gradient: Can be determined from the hydraulic head gradient close to the downstream edge.
- (D) Permeability: Cannot be determined from a flow-net. Permeability is an intrinsic soil characteristic requiring laboratory or field testing.

Step 3: Summary of Obtainable Data.
In summary, a flow-net allows for the determination of parameters A, B, and C.