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[raveeleo]

Dear SEFI'ans
Hat's off to Er. Mr. N Subramanian sir, Er. Mr.T Rangarajan sir,  Er. Mr.Vivek,  Er. Mr.Suraj, Er. Mr.Vikrem jeet, Er. Mr Malik, Er. Mr. Indrajir, Er. Ms Sangeeta Wij..... and the list is Endless for your support to the STRUCTURAL ENGINEERS.

I've been ON an OFF to SEFI, and also miss a lot of Tempting/debatable/interesting and many more  topics in SEFI, since there is no internet access i our office.


back to the query
1. What type of soil is suitable for back filling?
2. The soil is excavated with the attached Properties.
3. Is there any standard value w.r.t the attached test Report
4. the Test Concucted by Ventateswara University
Thank You all
GOD BLESS
ravee Kumar C K

[vikram.jeet]

Dear Er Ravi Kumar ,

In case of an earth retaining structure
Free draining coarse grained soils are most suitable for backfill material
behind abutments and other earth retaining structures.Further a 600 mm  
thick uniform layer of filter media shall also be provided at back of wall
for full height from backfilled level. Weep holes at spacing not exceeding
1.0m in both directions in wall need to be provided for release of hydrostatic  
pressure.
Kindly refer to IRC 78 Appendix-6 wherein properties of backfill
materials are provided on basis of anticipated embankment
performance.

In case of building Basements
The excavated earth is generally used as backfilled material with  
plinth protection all- around the building.Basement wall outer surface
must have protective water proofing .  

best regards

vikramjeet
-- ­­

Posted via Email

[suraj]

Soil Samples
Sample 1 appears to be better.
Silt & Clay being 14.2%
Liquid Limit being OK in both samples
PI should be around 6
Max DD is better in sample 1
OMC is OK in both cases.
Properties of sand not mentioned.
In case, sand is coarse, fine sand can be added to reduce the LL.
In fact, non plastic fill material is most suitable.
It could be selected from excavated material or imported from source.
It can also depend whether or not, fill is meant for below structures or non structures or general layers.
Regards

[raveeleo]

Dear all
Extremly sorry for not mentioninig the Purpose.
Thanks to Suraj sir

The Purpose is to back fill on the foundations

This Soil is excavated and the same soil is used to backfill to a depth of 1.75m

ravee

[suraj]

Fills
For structural fill, 98 % FD is required
For non structural fills, 95 % FD is adequate.
For general fills, 90 to 95% FD is adequate.
For fills more than 1 m below foundations, 90 to 95% Fd would do.
Check which composition provides such FD
Regards

[sspawar]

Dear Mr. Ravee and all

My findings are as follows:

1. What type of soil is suitable for back filling?

§. Both samples are OK  for the purpose of backfill.
The excavated earth is generally used as backfilled material if its suitablilty has been tested- unlike If BC soil is taken out  - it will not be suitable for back fill.

2. The soil is excavated with the attached Properties.

§.OK, the whole soil strata  is good for back filling  on/around foundations.

3. Is there any standard value w.r.t the attached test Report

§.Yes, There are certain Standard values - as diffferent limits and ranges are specified in MORTH Specification as well as IRC 78, though these specs are related to Roads & Bridges and air field works. But it can be adapted for any backfilling ( Filling around and above foundations)
Secondly in IS 1498-1970, some guide lines with characteristics are given.
Refer attached Doc file.

4. the Test Concucted by Ventateswara University

§.Two test  samples are exibiting - little uncommon report.

Where in two samples (silt+ clay) percent is 14.6% and 49.15%, and respective  FSI and PI are  being decreased. Generally it should be incresed.
Such behavior of soil would be more clear, if complete Sieve analysis result will be given.( from coarser to finer  - 75mm---- 4.75mm --- 2mm --- 425 μ----- 75μ  ---- residuals)

Regards

[bkkk]

Sir

It appears that  soil type 1 is better than type 2 soil as the former contains lesser amounts of silt and clay. The swelling properties of clay may spoil the floor resting  above. Hence it  is prudent to avoid clayey materials and to go for  non cohesive materials like sand even for filling purposes.

Er. Balaji venkateswaran

[sspawar]