Q1: Flow net is used for the determination of

ANS:E - all the above.

1. Quantity of Seepage: By analyzing the flow channels and equipotential lines, engineers can estimate the quantity of water passing through a given cross-section of soil or rock. The spacing of flow channels and equipotential lines provides information about the flow rate and direction of seepage.
2. Hydrostatic Pressure: Hydrostatic pressure refers to the pressure exerted by a fluid at rest due to the weight of the fluid above it. In a flow net, the spacing between the equipotential lines represents the hydraulic head, which is related to the pressure exerted by the water. By analyzing the spacing of the equipotential lines, engineers can determine the hydrostatic pressure distribution within the soil mass.
3. Seepage Pressure: Seepage pressure refers to the excess pressure exerted by flowing water within the soil mass. It is typically caused by the flow of water through soil pores or fractures. Flow nets help engineers visualize the flow patterns and gradients within the soil mass, allowing them to estimate the seepage pressure at different points.
4. Exit Gradient: The exit gradient represents the ratio of the hydraulic gradient (change in hydraulic head per unit distance) to the critical hydraulic gradient at the exit point of the flow. It indicates the stability of the soil mass and the potential for piping or erosion at the exit point. By analyzing the flow net, engineers can determine the exit gradient and assess the risk of soil instability or erosion.