From a flownet which of the following information can be obtained 1. Rate of flow 2. Pore water pressure 3. Exit gradient 4. Permeability Select the correct answer using the codes given below:?

Option 2 : 1, 2 and 3

Flow Nets:

It is a graphical solution to the Laplace equation for two-dimensional seepage flow. Two orthogonal sets of curves forming a flow net are:

• Equi potential lines → connecting points of the equal total head
• Flow lines → indicating the direction of seepage down under a hydraulic gradient.

In the case of isotropic soil, these lines are orthogonal to each other but need not be orthogonal in anisotropic soil.

Application of flow net is as follows:

1. Determination of seepage
2. Determination of hydrostatic pressure
3. Determination of seepage pressure
4. Determination of exit gradient

Various methods of obtaining flow nets are: 

1) Graphical method

2) Electrical Analogy method

3) Soil Model

4) Plastic Model

5) Solution of Laplace equation/Analytical method.

Sand model is not used to obtain flow nets.