Numerical of G.I. Method - Design of Highway Pavements - Transportation Engineering - I

TL;DR

Calculating the thickness of a pavement using the group index method, based on soil data such as % passing 75 micrometer sieve, liquid weight, and plastic limit.

Transcript

hello students today we are going to solve numerical of group index method question is given as a soil subgrade has following data soil portion passing 75 micrometer sieve is equal to 60 percent liquid weight is equals to 45 percent and plastic limit is equals to 20 percent find out the thickness of pavement required for above soils upgrade if thic... Read More

Key Insights

• 🫰 The group index method is commonly used in pavement design to assess the suitability of soil and determine pavement thickness.
• ⛔ Soil properties like particle size distribution, liquid limit, and plastic limit are considered in the group index calculation.
• 🧡 The group index value falls within a range in a table, which corresponds to a specific thickness value for the pavement layer.

Questions & Answers

Q: What is the purpose of determining the group index value in pavement design?

The group index value is used to classify the soil and estimate its relative strength, which is crucial for designing the thickness of the pavement layer.

Q: How is the group index value calculated?

The group index value is calculated using the formula: group index = 0.2a + 0.005ac + 0.01bd, where a, b, c, d are determined based on the given soil data.

Q: What is the significance of the abcd values in the group index formula?

The abcd values represent various characteristics of the soil, such as its particle size distribution, liquid limit, plastic limit, and velocity index, which collectively determine the group index value.

Q: How is the thickness of the pavement calculated using the group index value?

The thickness can be determined by interpolating the given values in the table based on the group index value, using the formula provided in the content.

Summary & Key Takeaways

• Soil subgrade data is provided, including % passing 75 micrometer sieve (60%), liquid weight (45%), and plastic limit (20%).

• The group index formula is used to find the group index value, which is 11.625 in this case.

• Based on the group index value and the values given in a table, the thickness of the pavement is estimated to be 67.2 cm.