Translate

Group index of soil

  • Group index of soil is a number used to refer the quality of soil used as a subgrade material in highway construction. 
  • Group index of soil is also used in AASHTO classification of soil. In AASHTO soil classification, group index is also included along with soil group and subgroup.
  • Group index of soil as a subgrade material is calculated using liquid limit,  plastic limit, plasticity index and % passing from US sieve #200 (i.e, 0.075 mm opening sieve). 
Note:  Plasticity index, PI = (liquid limit - plastic limit) 
  • So,  group index of soil can be defined as the combination of :
    1.  Partial group index obtained from liquid limit. 
    2. Partial group index obtained from plasticity index.

Group index of soil Formula

GI = (F₂₀₀-35) [0.2+0.005(LL-40)] + 0.01(F₂₀₀-15)(PI-10)

Here, (F₂₀₀ -35) [0.2+0.005(LL-40)] = partial group index obtained from liquid limit 

0.01(F₂₀₀ -15) (PI-10) = partial group index obtained from plasticity index

Note : In short form, the GI formula can also be written as

GI = 0.2a + 0.005ac + 0.01bd

here, a = (% passing # 200 sieve)-35
b = (%passing #200 sieve)-15
c =(LL-40)
d = (PI-10)
  • Group index of soil is always rounded off to nearest whole number. If group index of soil comes to be negative , then group index of soil in this case is considered zero.
  • The value of group index of soil ranges from 0 to 20. A soil having lower group index value is considered better subgrade material in comparison to that of soil having higher group index value.

  • In AASHTO soil classification system, the group index value for
    • Coarse grained soil
      •  A-1-a, A-1-b,  A-2-4,  A-2-5,  A-3, GI= 0
      • A-2-6 and A-2-7 , GI = 0.01(F₂₀₀-15)(PI-10) ,i.e, partial group index obtained from plasticity index.
    • Fine grained soil
      • GI = (F₂₀₀-35)[0.2+0.005(LL-40)] + 0.01(F₂₀₀-15)(PI-10)
Note : For coarse grained soil, the partial group index obtained from liquid limit is neglected.



19 comments:

  1. This comment has been removed by the author.

    ReplyDelete
  2. Good Blog, was very helpful also if you want Nut and Bolt Aashish Steel is a good option to go with. We are a Bolt Manufacturer in India and the best nut and bolt manufacturer.

    ReplyDelete
  3. Good Blog, was very helpful also if you want Alloy steel pipe Bright Steel Centre is a good option to go with. We are an Alloy steel pipe manufacturer in India and the best Carbon Steel pipe Manufacturer in India

    ReplyDelete
  4. Thank you for sharing this important information and helping us achieve our aim. You can visit here  Shashwat Stainless Inc, ERW Pipes Manufacturer in India, ERW Pipe Suppliers in Dubai, ERW Pipe Suppliers in UAE

    ReplyDelete
  5. This is a really good article! I appreciate you sharing this knowledge.. Look into it. Girish Metal India as well. We are also a leading SS Round Bar Supplier & Stainless Steel Round bar Manufacturer in India.

    ReplyDelete
  6. Thank you for this amazing blog, for posting this vital information with all of us.
    For more info visit: Trimac Piping Solutions
    You can also visit: ASME B16.47 Series B flanges manufacturer in India.

    ReplyDelete
  7. The details you have shared here are very instructive as it contains some best knowledge which is extremely helpful on my behalf. Thanks for posting it. Hot Finish IS4923 YST310 CHS.

    ReplyDelete
  8. Yes, It is very useful and informative article. Which provide best knowledge and your presenting way it’s also better. Thank you for this article. We also producing Stainless Steel 304 Hex Bolt at premium quality. You must visit here.

    ReplyDelete
  9. Thankyou for sharing this valuable article. I hope that you will continuously provide this kind of informative article to us. We are grateful to you And we also offer a 304 Stainless Steel Round bar in best quality.

    ReplyDelete
  10. I read your article. It’s a very informative. I think you have better knowledge about it. So, I thought you should write article on Stainless Steel 304 Bolt.

    ReplyDelete
  11. Thankyou for sharing this article. Your article have informative and authentic points. We also manufacturer of Duplex 2205 Plate. You must visit and check it. We provide high quality of Duplex Steel Sheets and Plates.

    ReplyDelete
  12. Thanks for this article, I read your article. It is very useful. We have various range of Stainless Steel Foil like 304 Stainless Steel Foil, 310 SS Foil. We offer premium quality of Foil.

    ReplyDelete
  13. You have worked nicely with your insights that makes our work easy. The information you have provided is really factual and significant for us. Keep sharing these types of article. Compression Tube Fittings

    ReplyDelete
  14. This comment has been removed by the author.

    ReplyDelete
  15. Great Blog! This post gives a better idea. Thanks for the useful information. I hope you will share some more content. Please keep sharing!

    Electrofusion

    ReplyDelete
  16. This comment has been removed by the author.

    ReplyDelete

Group index of soil

Group index of soil is a number used to refer the quality of soil used as a subgrade material in highway construction.  Group index of soil ...