Experiment No.:
Date:
Experiment Title:
Determination of Field Density of Soil by Core Cutter Method
Objective:
To determine the field density of soil using the Core Cutter Method, following the procedure outlined in IS 2720 (Part 29): 1975.
Apparatus Required:
- Core Cutter (Standard dimensions: 100 mm internal diameter and 130 mm height)
- Steel Rammer (9 kg weight with a drop height of 310 mm)
- Weighing Balance (Accurate to 1 g)
- Steel Rule (For measuring the dimensions of the core cutter)
- Straight Edge (For trimming excess soil from the core cutter)
- Moisture Content Containers
- Oven (For moisture content determination)
- Desiccator
- Chisel and Hammer (For removing the core cutter from the soil)
Theory:
The Core Cutter Method is used to determine the in-situ density of soil, which is essential for analyzing soil compaction at construction sites. In this method, a core cutter is driven into the soil, and the soil sample collected in the cutter is weighed to calculate the field density using the following formula:
Where:
- ρ = Field Density (g/cm³ or kg/m³)
- W_s = Weight of soil sample (g or kg)
- V_c = Volume of the core cutter (cm³ or m³), calculated as
- d = Internal diameter of the core cutter (cm)
- h = Height of the core cutter (cm)
Procedure:
Measure the Core Cutter:
- Measure the internal diameter (d) and height (h) of the core cutter using a steel rule and calculate its volume using the formula:
Drive the Core Cutter into Soil:
- Place the core cutter on the soil surface.
- Using the steel rammer, drive the cutter into the soil until its top is flush with the soil surface.
Extract the Core Cutter:
- Carefully dig around the core cutter and extract it without disturbing the soil inside it.
Trim and Weigh the Soil:
- Use a straight edge to trim off excess soil from the top and bottom of the core cutter.
- Weigh the core cutter with the soil sample and record the weight as W1.
Weigh the Empty Core Cutter:
- Weigh the empty core cutter and record its weight as W2.
Determine the Field Density:
- Calculate the weight of the soil sample as:
- Now calculate the field density (ρ) using the formula:
Moisture Content Determination:
- Take a small portion of the soil sample and place it in a moisture content container.
- Dry the sample in an oven at 110°C for 24 hours and calculate the moisture content using the formula:
Where:
- W_w = Weight of wet soil
- W_d = Weight of dry soil
Observation Table:
Observation | Measurement |
---|---|
Weight of Core Cutter + Soil (W1) | ______ g |
Weight of Empty Core Cutter (W2) | ______ g |
Weight of Soil Sample (W_s = W1 - W2) | ______ g |
Volume of Core Cutter (V_c) | ______ cm³ |
Field Density (ρ) | ______ g/cm³ |
Moisture Content (w) | ______ % |
Results:
- The field density of the given soil sample is found to be _______ g/cm³.
Diagram of Core Cutter Method:
Conclusion:
The field density of the given soil sample was determined using the Core Cutter Method according to IS 2720 (Part 29): 1975. This method provides accurate field density, essential for analyzing soil compaction in construction projects.
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