Engineering

How to Calculate and Solve for Unit Weight | Soil Mechanics and Foundation

Last Updated on April 17, 2024

The image above represents unit weight. To calculate unit weight, three essential parameters are needed and these parameters are Bulk density of soil (g), Density of water (ρwand Unit Weight of water (γw).

The formula for calculating unit weight:

Γ = g . γw / ρw

Where:

Γ = Unit Weight
g = Bulk Density of Soil
ρw = Density of Water
γw = Unit Weight of Water

Let’s solve an example;
Find the unit weight when the bulk density of soil is 7, the density of water is 16 and the unit weight of water is 9.

This implies that;

g = Bulk Density of Soil = 7
ρw = Density of Water = 16
γw = Unit Weight of Water = 9

Γ = g . γw / ρw
That is, Γ = (7) . (9) / 16
Γ = 63 / 16
Γ = 3.93

Therefore, the unit weight is 3.93.

Calculating for the Bulk Density of Soil when the Unit Weight, the Density of Water and the Unit Weight of Water are Given

g = Γ x ρw / γw

Where;

g = Bulk Density of Soil
Γ = Unit Weight
ρw = Density of Water
γw = Unit Weight of Water

Let’s solve an example;
Find the bulk density of soil when the unit weight is 42, the density of water is 14 and the unit weight of water is 7.

This implies that;

Γ = Unit Weight = 42
ρw = Density of Water = 14
γw = Unit Weight of Water = 7

g = Γ x ρw / γw
So, g = 42 x 14 / 7
g = 588 / 7
g = 84

Therefore, the bulk density of soil is 84.

Read more: How to Calculate and Solve for Specific Gravity of Soil Particle | Soil Mechanics and Foundation

Calculating for the Density of Water when the Unit Weight, the Bulk Density of Soil and the Unit Weight of Water are Given

ρw = g x γw / Γ

Where;

ρw = Density of Water
Γ = Unit Weight
g = Bulk Density of Soil
γw = Unit Weight of Water

Let’s solve an example;
Given that the unit weight is 20, the bulk density of soil is 10 and unit weight of water is 6.

This implies that;

Γ = Unit Weight = 20
g = Bulk Density of Soil = 10
γw = Unit Weight of Water = 6

ρw = g x γw / Γ
Then, ρw = 10 x 6 / 20
ρw = 60 / 20
ρw = 3

Therefore, the density of water is 3.

Calculating for the Unit Weight of Water when the Unit Weight, the Bulk Density of Soil and the Density of Water are Given

γw = Γ x ρw / g

Where;

γw = Unit Weight of Water
Γ = Unit Weight
g = Bulk Density of Soil
ρw = Density of Water

Let’s solve an example;
Find the unit weight of water when the unit weight is 18, the bulk density of soil is 8 and the density of water is 2.

This implies that;

Γ = Unit Weight = 18
g = Bulk Density of Soil = 8
ρw = Density of Water =2

γw = Γ x ρw / g
So, γw = 18 x 2 / 8
γw = 36 / 8
γw = 4.5

Therefore, the unit weight of water is 4.5.

How to Calculate Unit Weight in Soil Mechanics and Foundation Using Nickzom Calculator

Nickzom Calculator – The Calculator Encyclopedia is capable of calculating the unit weight.

To get the answer and workings of the unit weight using the Nickzom Calculator – The Calculator Encyclopedia. First, you need to obtain the app.

You can get this app via any of these means:

Web – https://www.nickzom.org/calculator-plus

To get access to the professional version via web, you need to register and subscribe for NGN 2,000 per annum to have utter access to all functionalities.
You can also try the demo version via https://www.nickzom.org/calculator

Android (Paid) – https://play.google.com/store/apps/details?id=org.nickzom.nickzomcalculator
Android (Free) – https://play.google.com/store/apps/details?id=com.nickzom.nickzomcalculator
Apple (Paid) – https://itunes.apple.com/us/app/nickzom-calculator/id1331162702?mt=8
Once, you have obtained the calculator encyclopedia app, proceed to the Calculator Map, then click on Agricultural under Engineering.

Now, Click on Soil Mechanics and Foundation under Agricultural

Now, Click on Unit Weight under Soil Mechanics and Foundation

How to Calculate and Solve for Unit Weight | Soil Mechanics and Foundation

The screenshot below displays the page or activity to enter your values, to get the answer for the unit weight according to the respective parameters which is the Bulk density of soil (g), Density of water (ρwand Unit Weight of water (γw).

Now, enter the values appropriately and accordingly for the parameters as required by the Bulk density of soil (g) is 7, Density of water (ρwis 16 and Unit Weight of water (γw) is 9.

How to Calculate and Solve for Unit Weight | Soil Mechanics and Foundation

Finally, Click on Calculate

How to Calculate and Solve for Unit Weight | Soil Mechanics and Foundation

As you can see from the screenshot above, Nickzom Calculator– The Calculator Encyclopedia solves for the unit weight and presents the formula, workings and steps too.

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