## How to Calculate and Solve for Soil Load on Rigid Pipe | Irrigation Water Requirement

The image above represents soil load on rigid pipe.

To compute for soil load on rigid pipe, three essential parameters are needed and these parameters are Load Co-efficient for Ditch Conduits (Cd), Unit Weight of Fill Material (w) and Width of Ditch at Top of Conduit (Bd).

The formula for calculating Soil Load on Rigid Pipe:

Wc = CdwBd²

Where:

Wc = Soil Load on Rigid Pipe
Cd = Load Co-efficient for Ditch Conduits
w = Unit Weight of Fill Material
Bd = Width of Ditch at Top of Conduit

Let’s Solve an example;
Find the soil load on rigid pipe when the load co-efficient for ditch conduits is 16, the unit weight of fill material is 6 and width of ditch at top of conduit is 2.

This implies that;

Cd = Load Co-efficient for Ditch Conduits = 16
w = Unit Weight of Fill Material = 6
Bd = Width of Ditch at Top of Conduit = 2

Wc = CdwBd²
Wc = (16)(6)(2)²
Wc = (16)(6)(4)
Wc = 384

Therefore, the soil load on rigid pipe is 384.

Calculating for the Load Co-efficient for Ditch Conduits when the Soil Load on Rigid Pipe, the Unit Weight of Fill Material and the Width of Ditch at Top of Conduit is Given.

Cd = Wc / w x Bd2

Where;

Cd = Load Co-efficient for Ditch Conduits
Wc = Soil Load on Rigid Pipe
w = Unit Weight of Fill Material
Bd = Width of Ditch at Top of Conduit

Let’s Solve an example;
Find the load co-efficient for ditch conduits when the soil load on rigid pipe is 40, the unit weight of fill material is 4 and the Width of ditch at top of conduit is 2.

This implies that;

Wc = Soil Load on Rigid Pipe = 40
w = Unit Weight of Fill Material = 4
Bd = Width of Ditch at Top of Conduit = 2

Cd = Wc / w x Bd2
Cd = 40 / 4 x 22
Cd = 40 / 4 x 4
Cd = 40 / 16
Cd = 2.5

Therefore, the load co-efficient for ditch conduits is 2.5.