Specific Gravity of Soil Solids by Pycnometer Method Calculator

Specific Gravity Formula:

\[ G = \frac{w2 - w1}{(w4 - w3) + (w2 - w1)} \]

Weight of Empty Pycnometer (w1):

Weight of Empty Pycnometer and Moist Soil (w2):

Weight of Empty Pycnometer, Soil and Water (w3):

Weight of Empty Pycnometer and Water (w4):

Specific Gravity of Soil Solids (G):

1. What is Specific Gravity of Soil Solids by Pycnometer Method?

Definition: This method determines the specific gravity of soil solids, which is the ratio of the weight of soil solids to the weight of an equal volume of water.

Purpose: It's a fundamental property used in soil mechanics for phase relationships, density calculations, and classification of soils.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ G = \frac{w2 - w1}{(w4 - w3) + (w2 - w1)} \]

Where:

\( G \) — Specific Gravity of Soil Solids
\( w1 \) — Weight of Empty Pycnometer (g)
\( w2 \) — Weight of Empty Pycnometer and Moist Soil (g)
\( w3 \) — Weight of Empty Pycnometer, Soil and Water (g)
\( w4 \) — Weight of Empty Pycnometer and Water (g)

Explanation: The formula compares the weight of soil solids to the weight of an equivalent volume of water.

3. Importance of Specific Gravity Measurement

Details: Specific gravity is crucial for calculating void ratio, porosity, degree of saturation, and other soil properties in geotechnical engineering.

4. Using the Calculator

Tips: Enter all weights in grams. The ±5% indicates the typical accuracy range for pycnometer measurements.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical range for soil specific gravity?
A: Most soils range between 2.60 and 2.80, with organic soils being lower (1.2-2.0) and heavy minerals higher (up to 3.2).

Q2: Why use a pycnometer method?
A: It provides accurate volume measurements for irregular soil particles by water displacement.

Q3: How should I prepare the soil sample?
A: Soil should be oven-dried at 110°C and pulverized to pass a No. 10 sieve (2mm openings).

Q4: What temperature should the water be?
A: Measurements should be at a standard temperature (usually 20°C) as water density varies with temperature.

Q5: How many decimal places are significant?
A: Specific gravity is typically reported to 3 decimal places (e.g., 2.675).