Pengujian CBR (California Bearing Ratio) Unsoaked - Praktikum Survey dan Penyelidikan Geoteknik

Summary

This video tutorial explains the California Bearing Ratio (CBR) test, a critical assessment for evaluating soil strength in construction. It details the purpose of the CBR test, the equipment used, and a step-by-step procedure for preparing soil samples and conducting the test. The process involves measuring soil density, mixing with water, and compacting to determine the CBR values. Results indicate the soil's suitability for road construction, with recorded CBR values reflecting medium quality. The video aims to provide useful insights into soil testing for engineering applications, encouraging better understanding and practices in civil engineering.

Takeaways

• 📊 The California Bearing Ratio (CBR) test evaluates the strength and load-bearing capacity of soil, which is essential for construction.
• 🔍 CBR value is a percentage that compares the pressure needed to penetrate a soil sample versus a standard material.
• 🏗️ This test is crucial for assessing soil suitability for airport runways and road construction.
• 🛠️ Key equipment for the CBR test includes a CBR testing machine, compaction cylinder, and penetration piston.
• ⚖️ Soil samples, typically sandy soil, must pass through a No. 4 sieve for accurate testing.
• 💧 The testing process involves mixing the soil with a specific amount of water before compaction.
• 🔨 The soil is compacted in layers, with a standard number of blows applied to ensure consistency.
• 📏 Measurements are taken during the test to record penetration depth at various load levels.
• 🧪 Data analysis involves calculating moisture content and CBR values from the compacted soil samples.
• ✅ The results indicate soil quality, with specific CBR values categorizing the soil for potential use in construction.

Q & A

What is the purpose of the California Bearing Ratio (CBR) test?

The purpose of the CBR test is to determine the bearing capacity of soil, which is essential for evaluating its suitability for construction projects such as pavements and airfields.

How is the CBR value defined?

The CBR value is defined as the percentage ratio of the pressure required to penetrate the soil with a 3 square inch circular piston at a specific penetration rate compared to the pressure needed to penetrate a standard material.

What equipment is essential for conducting the CBR test?

Essential equipment includes the CBR testing machine, compaction cylinders, loading rings, a hammer for compaction, measuring tools like graduated cylinders and balances, and miscellaneous supplies such as plastic sheets and spirit for combustion.

What are the key steps in the CBR test procedure?

Key steps include preparing the testing site, compacting the soil in layers within a cylinder, adding water, conducting penetration tests, and analyzing soil samples for moisture content after combustion.

How is the soil sample prepared before the CBR test?

The soil sample is prepared by weighing 5 kg of soil, mixing it with a specific amount of water, and then placing it into the compaction cylinder in layers, which are compacted using a hammer.

What measurements are taken during the CBR test?

Measurements taken during the CBR test include the diameter and height of the soil sample, the penetration depth during the test, and the weights of the soil samples before and after combustion.

What were the CBR values obtained from the test?

The CBR values obtained were 9.2539% at a penetration depth of 2.54 mm and 11.062% at a penetration depth of 5.08 mm.

What does the CBR value indicate about the soil quality?

The CBR value indicates the quality of the soil; in this case, the results suggest that the soil is of moderate quality, making it suitable for use as subgrade material in road construction.

What is the significance of measuring the moisture content of the soil?

Measuring the moisture content of the soil is significant because it affects the soil's strength and stability, influencing its performance as a subgrade material in construction.

How does the CBR test contribute to civil engineering projects?

The CBR test provides essential data that civil engineers use to ensure the structural integrity and suitability of soil for pavement designs and other construction applications.