Calcium carbide method for determination of water content in field embankments

Introduction:

Water content in field embankments is an important parameter to determine the stability of slopes and foundations. Several methods are available to determine the water content in soil. One of the commonly used methods is the calcium carbide method.

Principle:

The principle of the calcium carbide method is based on the reaction between water and calcium carbide. Calcium carbide reacts with water to produce acetylene gas, which can be measured using a pressure gauge. The amount of acetylene gas produced is proportional to the amount of water in the soil.

Procedure:

The following steps are involved in the calcium carbide method:

1. Take a representative soil sample from the field embankment.

2. Weigh the sample and record the weight as W1.

3. Crush the soil sample and mix it thoroughly.

4. Take about 10 g of the soil sample and place it in a metal container.

5. Add about 2 g of calcium carbide to the soil sample in the container.

6. Immediately close the container with a lid and shake it vigorously for about 30 seconds.

7. Place the container on a pressure gauge and open the valve to allow the acetylene gas to enter the gauge.

8. Record the pressure reading on the gauge after about 3 minutes.

9. Repeat the procedure with another soil sample to obtain a more accurate result.

Calculation:

The water content in the soil can be calculated using the following formula:

Water content (%) = (Volume of acetylene gas produced / Weight of soil sample) x 100

where the volume of acetylene gas produced is calculated using the pressure gauge reading and the ideal gas law.

Advantages:

The calcium carbide method has the following advantages:

1. It is a quick and easy method to determine the water content in field embankments.

2. It requires simple equipment and is relatively inexpensive.

3. It can be used in the field without the need for a laboratory.

Limitations:

The calcium carbide method has the following limitations:

1. It is not suitable for soils with high organic content or high salinity.

2. It may give inaccurate results for soils with high clay content.

3. It may give false results if the calcium carbide is not of good quality.

Conclusion:

The calcium carbide method is a quick and easy method to determine the water content in field embankments. However, it has certain limitations and should be used with caution. It is important to follow the procedure carefully and use good quality calcium carbide to obtain accurate results.

Answer is (D).....this method is quickest method -(3 to 5 minutes )
Calcium Carbide reacts with soil moisture to form acytelene gass (C2H2)
The amount of gass released represent water content in soil
calcium carbide पानी के प्रति बड़ा संवेदनशील होता है
इसका प्रयोग liquid, solid or gas तीनों में से किसी भी state मैं किया जा सकता है
this is a field method this method is not used for Organic soil or gypsum