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How do you draw a flow net diagram in soil mechanics?

How do you draw a flow net diagram in soil mechanics?

The procedure for drawing the flow net can be divided into the following steps:

  1. First identify the hydraulic boundary conditions.
  2. Draw a trial flow line ABC adjacent to boundary line.
  3. Starting from the upstream end, divide the first flow channel into approximate squares.

What is Flow Nets in soil mechanics?

Flow net represents the flow of water through a soil graphically. Applications include calculation of uplift pressure, exit gradient, heaving and pore water pressure.

What is flow net diagram?

A flow net is a graphical representation of two-dimensional steady-state groundwater flow through aquifers. Construction of a flow net is often used for solving groundwater flow problems where the geometry makes analytical solutions impractical.

What are the types of water flow in the soil?

Generally three types of water movement within the soil are recognized –saturated flow, unsaturated flow and water vapour flow (Fig. 23.1). Water in the liquid phase moves through the water filled pores within the soil (saturated condition) under the influence of gravitational force.

What is submerged unit weight of soil?

Buoyant unit weight or submerged unit weight is the effective mass per unit volume when the soil is submerged below standing water or below the ground water table.

Why is clay less permeable than sand?

Is Clay more permeable than sand? Sand particles are easier for water to maneuver through the pore spaces while clay particles because of their flat shape and electrically charge state has a more difficult time making it way through the matrix of particles, in other words, sand is more permeable that clay.

How can soil permeability be reduced?

It is common practice to alter the soil structure to reduce permeability, for example, in irrigated agriculture through the puddling of rice fields and in civil engineering through the mechanical compaction* of earthen dams. Similar practices may be applied to fish-ponds to reduce water seepage.

What is flow water of the soil?

Definition. Soil water flow is conditioned by the existence of a gradient of the total potential of soil water in both, the soil fully saturated by water (saturated flow) as well as in soil not fully saturated by water (unsaturated flow).

How to draw flow net by hand soil mechanics?

Aq = b x 1 x k x i = bki where b = distance between the two flow lines. In Fig. 2.7 the figure ABCD is bounded by the same flow lines as figure AiBiCiD, and by the same equipotentials as figure A2B2C2D2.

How is a flow net used for seepage?

Fig. 2.7 Flow net for seepage beneath a dam. maximum along a path normal to the equipotentials and in isotropic soil the flow follows the paths of the steepest gradients, so that flow lines cross equipotential lines at right angles. Figure 2.7 shows a typical flow net representing seepage through a soil beneath a dam.

What do you need to know about flow net problems?

Note In flow net problems we assume that the permeability of the soil is uniform throughout the soil’s thickness.

What’s the best way to draw a flow net?

A soft pencil, a rubber and a pair of dividers or compasses are necessary. The first step is to draw in one flow line, upon the accuracy of which the final correctness of the flow net depends. There are various boundary conditions that help to position this first flow line, including: