GOVERNMENT OF INDIA MINISTRY OF RAILWAYS · issued by RDSO in November 2009 came under discussion. Eastern railway requested, ... Axle Load” issued by RDSO report no. RDSO/2007/GE:0014,

GOVERNMENT OF INDIAH k kjr ljdkj

MINISTRY OF RAILWAYSj sy e a= ky;

Consultancy ReportOn

Review of Blanket Thickness as per Guideline and Specification of Higher Axle

Load of New Line Between

Tarkeshwar-Bishnupur Section and Doubling Projects of Ambikakalna- Nabadwip Dham and Katwa-Patuli

Sections

Howrah Division: Eastern Railway

Consultancy No. RDSO/2010/GE: CR-0147ijke'kZ la[;k RDSO/2010/GE:CR-0147

tuojh 2011

Geo-technical Engineering DirectorateHkw&rduhdh bathfu;jh funs’kky;

Research Designs & Standards Organisationvuqla/kku vfHkdYi vkSj ekud laxBu

Lucknow – 226011y[kuÅ & 226011

FOR OFFICIAL USE ONLY

fo"k;&lwph

INDEX

dze fooj.k Particulars

i`"BPage

izkDdFku Preface

2

Lkkjka’k Synopsis

3

1. izLrkoukIntroduction

4

2. lanHkZReferences

4

3. v/;;u {ks=Scope of work

4

4. Site Details And Collection Of Field Data 4-6

5. e`nk uewukas dk fooj.k Details Of Soil Samples

7

6. fo'ys"k.k ]ijh{k.k ifj.kke®a ij fopkj foe'Kz ,oa laLrqfr;ka

Analysis & Discussion Of Test Results and Recommendations

7-18

7. LohÑ`frAcknowledgement

19

8.Annexures –¼i½ Specification of blanket material (Annexure I)¼ii½ Index Map ( Fig 1)

20

21

Page 1

PREFACE

This report is prepared on the basis of soil investigation and Soil samples collected by RDSO officials, and tested in Geo-technical Engineering lab of RDSO. Views expressed in this report are subjective and do not represent the views of the Ministry of Railways (Railway Board), Government of India. However same are subject to modification from time to time in the light of future developments on the topic.

This report is the property of the RDSO and is meant essentially for official use. It may not be loaned, reproduced in part /full or quoted as an authority without the permission of Director General, RDSO,

(Rajesh Agarwal) (Mahesh Kumar Gupta)Director/Geo-tech Engg. Executive Director/B&S

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SYNOPSIS

On Eastern Railway, large number of projects on new line and doubling are in progress. During one of M.E.’s visit item for review of blanket thickness as per Guidelines and specification for design of formation for heavy axle load of 2007, issued by RDSO in November 2009 came under discussion.

Eastern railway requested, RDSO to review the thickness of blanket given in (up to 25 ton axle load) Guidelines and specification for design of formation for heavy axle load report of new line between Tarkeshwar-Bishnupur section & doubling projects of Ambika Kalna-Nabadwip Dham and Katwa-Patuli sections of Howrah division, Eastern Railway.

On request of Railway, RDSO carried out detailed soil investigation and collected soil samples from site. These disturbed soil samples are tested in GE lab/RDSO. Present Report is based on strength criteria considering CBR value of subgrade layer, recommends specifications & thickness of two alternative systems of formation layers, viz.a conventional single blanket layer system over embankment fill and two layer system comprising blanket and prepared subgrade layer over the normal fill layers.

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1.0 INTRODUCTION

Case has been referred by Chief Engineer(Cons)/Co-ordination/Eastern Railway to RDSO to review the thickness of blanket as per Guidelines and specification for design of formation for heavy axle load report.

Accordingly, RDSO team along with railway officials investigated new line between Tarkeshwar-Bishnupur section & doubling projects of Ambika Kalna-Nabadwip Dham and Katwa-Patuli sections of Howrah division, Eastern Railway from 25.05.10 to 28.05.10. Subsequently, site observations were recorded & soil samples were collected from the location for testing at GE Laboratory, RDSO.

2.0 REFERENCE

CE/Con/Co-ordination/ER, vide letter no. CE/Con/W/1940/Pt.IV/ER, dated 16.03.10, referred RDSO to review the thickness of blanket as per Guidelines and specification for design of formation for heavy axle load report of new line between Tarkeshwar-Bishnupur section & doubling projects of Ambika Kalna-Nabadwip Dham and Katwa-Patuli sections of Howrah division, Eastern Railway.

3.0 SCOPE OF WORK

Soil exploration, testing and recommendations for the blanket thickness on the sections indicated vide (Para 2.0) above.

4.0 SITE DETAILS AND COLLECTION OF FIELD DATA

4.1 TARKESHWAR-BISHNUPUR SECTION:

Tarkeshwar is the terminal station of Sheoraphuli-Tarakeshwar broad gauge line branched off from the station Sheoraphuli on Howrah_Burdwan main line. The distance of Tarkeshwar is about 57 km from Howrah. This line was commissioned during January, 1884. The construction work from Tarkeshwar-Bishnupur via Arambagh approximate 84 km is in progress.On 25.05.10 & 27.05.10, RDSO team along with railway officials visited the Tarkeshwar-Bishnupur section. Eleven disturbed soil samples were collected. As per railway officials construction work of 52 km length,(from km 5.00 to km 35.00 and from km 62.75 to km 84.75) up to 25 ton axle load, is in progress. As per railway officials only classification tests has been done and SQ2 & SQ3 soils are not easily available in the nearby places. Total length of the project is 84.75 km. Acquisition of remaining land (approximately 27.75 km) is under process.

Earthwrok between Tarkeshwar-Bishnupur section

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Main observations are given below :

4.1.1 Km 0.00 to Km 5.00

Earthwork is completed and line is commissioned in April 2010.

4.1.2 Km 5.00 to Km 10.00

During site visit, earthwork was in progress.In the total stretch, soil from Mundeswari river side used as sub grade material. The blanket material was not approved and maximum height of bank is 7m. Three disturbed soil samples were collected.

4.1.3 Km 10.00 to Km 16.50

Earthwork is in progress. Maximum height of bank is 5 m. In the section, one disturbed soil sample collected.

4.1.4 Km 16.50 to Km 21.50

Work has been stopped as the contract is terminated and maximum height of bank is 5 m. Only one disturbed soil sample collected.

4.1.5 Km 21.50 to Km 25.00

Earthwork completed. In the section, blanket has been provided, hence one disturbed blanket material sample and one subgrade soil sample taken. The blanket thickness is 1m and maximum height of bank is 6 m.

4.1.6 Km 25.00 to Km 35.00

Earthwork is in progress. The maximum height of bank is 9.5 m. Two disturbed soil samples were collected.

4.1.7 Km 62.75 to Km 67.25/Km 17.50 to Km 22.00 (from Bishnupur side)

Earthwork was in progress. In the total stretch soil from Bankura district has been used as sub grade material. The blanket material yet not decided and maximum height of bank is 6 m. Two disturbed soil samples were collected.

4.1.8 Km 67.25 to 84.75/Km 0.00 to Km 17.50 (from Bishnupur side)

Earthwork is completed.

The factual information about height of bank etc has been given by railway officials during inspection.

4.2 AMBIKA KALNA-NABADWIP DHAM DOUBLING PROJECT :

Bandel-Katwa section is an electrified single line section. This section passes through Hooghly and Bardhman districts of west Bengal serving sub-divisions of the two districts viz. Chinsurah in Hooghly district, Kalna and Katwa in Bardhman district. Express trains including Jan Shatabdi Express to North Bengal are running via this route. In order to cater to the increasing passenger traffic over this section, the project has been sanctioned in 2010-2011.

On 26.05.10, RDSO team along with railway official investigate the Ambika Kalna (km 42.24)-Nabadwip Dham (km 65.53) section. As the construction work pertaining to formation was not started during visit, therefore only four disturbed sub-soil samples have been taken. As per railway officials tender work of above section is expected shortly. Bushes and cultivation of crops were observed on both sides of existing track. As per

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railway officials SQ2 & SQ3 soils are not easily available in the nearby places. Maximum height of bank is 6.0 m. Total length of the project is 23.29 km.

Existing track of Ambika Kalna -Nabadwip Dham section

4.3 KATWA-PATULI DOUBLING PROJECT:

Bandel-Katwa section is an electrified single line section. This section passes through Hooghly and Bardhman districts of west Bengal serving sub-divisions of the two districts viz. Tribeni in Hooghly district, Kalna and Katwa in Bardhman district. Express trains including Jann Shatabdi Express to North Bengal are running via this route. In order to cater to the increasing passenger traffic over this section, the project has been sanctioned in 2010-2011.

On 26.05.10, RDSO team along with railway official investigate the Katwa(km 104.70)-Patuli (km 87.00) section. As the construction work pertaining to formation was not started during visit, therefore only four disturbed sub-soil samples have been taken. Bushes and cultivation of crops was observed on both sides of existing track.As per railway officials tender work of above section is expected shortly. As per railway officials SQ2 & SQ3 soils are not easily available in the nearby places. Maximum height of bank is 4.5m. Total length of the project is 17.70 km.

Existing track of Katwa-Patuli Section

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5.0 DETAILS OF SOIL SAMPLES

Soil investigation was carried out by RDSO team from 25.05.10 to 28.05.10. During site investigation nineteen numbers of disturbed soil/blanket samples were collected from Tarkeshwar-Bishnupur section, Ambika Kalna-Nabadwip Dham and Katwa-Patuli sections of Howrah division, Eastern Railway. Details of disturbed samples collected from the locations given in Table-1.

Table-1SL Section Location Disturbed1 Tarkeshwar-Bishnupur km 5.500 1

2 Tarkeshwar-Bishnupur km 9.250 2




6 Tarkeshwar-Bishnupur km 32.375 27 Tarkeshwar-Bishnupur(From Bishnupur side) km 18.900 28 Ambika Kalna-Nabadwip Dham km 44.100 1

9 Ambika Kalna-Nabadwip Dham km 52.000 1



12 Katwa-Patuli km 87.900 113 Katwa-Patuli km 91.600 114 Katwa-Patuli km 97.000 1

15 Katwa-Patuli km 102.000 1

Total 19

These soil samples were tested in Geo-technical Engineering Laboratory at RDSO for the following tests:

(a) Soil Classification(b) Differential free swelling(c) Grain Size Analysis(d) California Bearing Ration (CBR)(e) Shrinkage limit(f) OMC & MDD(g) UCC test in saturation condition

6.0 ANALYSIS & DISCUSSION OF TEST RESULTS AND RECOMMENDATIONS:

To appraise the recommendations, the study of “Guideline and Specification for Design of Formation for Heavy Axle Load” is necessary and it is available at www.rdso.indianrailways.gov.in/Directorate/GeotechnicalEngineering/Geotechnicalreports.

General recommendation:

Blanket layer as per “Guideline and Specification for Design of Formation for Heavy Axle Load” issued by RDSO report no. RDSO/2007/GE:0014, Nov 2009, following should be adopted for thickness of blanket:

a) Two layer system [Blanket & prepared sub grade(PI<=12) on embankment fill]: 100 cm thick prepared sub grade (good/imported soil) with CBR >=7 generally but not <6 in isolated case and MDD=98% should be provided. Over prepared sub

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http://www.rdso.indianrailways.gov.in/Directorate/GeotechnicalEngineering/Geotechnicalreports

grade 30 cm/45 cm blanket well graded sand gravel layer should be provided if prepared sub grade is SQ3/SQ2 soil respectively.

b) If option a) is not feasible due to site condition or economically, single layer of 100 cm thick blanket for SQ1 (SQ1, only with dispensation of PCE/CAO) or 60 cm for SQ3

or 75 cm for SQ2 soil may be provided.Blanket should be provided in full width of formation. Specification of blanket materials is placed at Annexure-I.

6.1 TARKESHWAR-BISHNUPUR SECTION :

6.1.1 Km 5.00 to Km 10.00

Three disturbed soil samples were collected.

Soil Properties

SNo Soil Parameters

Subgrade Soilat

km 5.300(D1)

Subgrade Soilat

km 9.250(D3)

Ground Soilat

km 9.250(D2)

1 Classification CI CH CI

2 Particle size distributionGravel (%) 00 00 00Sand (%) 15 20 18Silt (%) 55 63 74Clay (%) 30 17 08

Fines passing 75µ sieve (%) 85 80 823 Cu - - 20.83

Cc - - 0.534 Consistency limits:

Liquid Limit 46 54 41Plastic Limit 18 23 21

Plasticity Index 28 31 20Shrinkage limit 12.6 12.3 -

Differential Free Swell 30 40 -5 OMC (%) 10.00 10.50 10.80

MDD (g/cm3) 1.97 1.79 1.946 California bearing ratio

CBR value at 2.5 mm penetration in %

1.17 1.53 5.91


0.92 1.47 7.01

7 Shear Parameters Unconfined Compressive strength, Cu (kg/cm2)

0.494 0.508 0.616

Grain size distribution & test for consistency conducted on the collected soil samples classify the soil as CI/CH (Formation soil) and CI (Ground soil).

Shrinkage limit varies from 12.3% to 12.6%, shows soil is moderate shrinkable and very near to the borderline of high shrinkable soil.

Differential free swell index varies from 30 to 40 for formation soil indicates that formation soil is not swelling in nature.

Subgrade soil contains fines upto 80% to 85% and liquid limit varying from 46% to 54%. The PI varies from 28% to 31%. The soil is cohesive and having quite low MDD

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value at km 9.250.

Undrained shear strength, Cu of ground soil and subgrade soil is more than the stipulated value.

California bearing ratio of embankment fill material at km 5.300 is 1.17 and at km 9.250 is 1.53, which is less than the stipulated value.

RECOMMENDATION:

From lab test results soil in this section does not fall in SQ2 and SQ3 category.

As per lab test results, percentage of fines at km 5.300 is 85% and CBR value is 1.17 and percentage of fines at km 9.250 is 80% and CBR value is 1.53.

As per GE:0014, Nov 2009, this soil cannot be used as subgrade. As the fill material is not desirable, the thickness of blanket at this location cannot be suggested. Alternative construction method of sandwich layer can be explored.

As per Para 5.1.1(b) of “Guidelines for earthwork in railway projects”-July 2003, for top 3m of embankment, clays and silts of high plasticity (CH & MH) should be avoided. The sub grade soil at km 9.250 is of CH type, it should be avoided, as it will create formation troubles in future.

As per lab test results, at km 9.250 the subsoil is CI and subgrade soil is CH. As CI soil is already available as subsoil, it is not clear why CH type of soil is used for subgrade.

As the maximum height of bank is 7m therefore, at this location slope stability analysis should be carried out using effective soil shear parameters.

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6.1.2 Km 10.00 to Km 16.50

In the section, one disturbed soil sample collected.

Soil PropertiesSNo

Soil Parameters Subgrade Soil at km 16,450(D4)

1 Classification CH2 Particle size distribution

Gravel (%) 05Sand (%) 17Silt (%) 57Clay (%) 21

Fines passing 75µ sieve (%) 783 Cu -

Cc -4 Consistency limits:

Liquid Limit 52Plastic Limit 22

Plasticity Index 30Shrinkage limit -

Differential Free Swell -5 OMC (%) 10.20

MDD (g/cm3) 1.906 California bearing ratio

CBR value at 2.5 mm penetration in % 1.02CBR value at 5.0 mm penetration in % 0.88

7 Shear Parameters Unconfined Compressive strength, Cu

(kg/cm2) 0.499

Grain size distribution & test for consistency conducted on the collected soil samples classify the soil as CH (Formation soil).

Soil contains fines upto 78% and liquid limit is 52. The PI of soil is 30. The soil is cohesive.

California bearing ratio of embankment fill material is 1.02 which is less than the stipulated value.

RECOMMENDATIONS:

As per lab test results, percentage of fines at km 16.450 is 78% and CBR value is 1.02.


As per para 5.1.1(b) of “Guidelines for earthwork in railway projects”-July 2003, for top 3m of embankment clays and silts of high plasticity (CH & MH) should be avoided. Therefore subgrade soil at km 16.450 is of CH type, it should be avoided, as it will create formation troubles in future.

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6.1.3 Km 16.50 to Km 21.50

Only one disturbed soil sample collected.

Soil Properties

SNo Soil Parameters Subgrade Soil at km 20.000(D9)

1 Classification CI2 Particle size distribution

Gravel (%) 00Sand (%) 16Silt (%) 57Clay (%) 27

Fines passing 75µ sieve (%) 843 Cu -

Cc -4 Consistency limits:

Liquid Limit 48Plastic Limit 23

Plasticity Index 25Shrinkage limit -

Differential Free Swell -5 OMC (%) 11.20

MDD (g/cm3) 1.8206 California bearing ratio

CBR value at 2.5 mm penetration in % 1.35CBR value at 5.0 mm penetration in % 1.27

7 Shear Parameters Unconfined Compressive strength, Cu

(kg/cm2) 0.526

Grain size distribution & test for consistency conducted on the collected soil samples classify the soil as CI (Formation soil).

Soil contains fines upto 84% and liquid limit is 48. The PI of soil is 25.


RECOMMENDATIONS:


As per GE:0014, Nov 2009, this soil cannot be used as subgrade. As the fill material is not desirable, hence thickness of blanket at this location cannot be suggested. Alternative construction method of sandwich layer can be explored.

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6.1.4 Km 21.50 to Km 25.00

One disturbed blanket material sample and one subgrade soil sample taken.

Soil Properties

SNo Soil Parameters

Blanket materialat

Km 23.850(D7)

Subgrade Soilat

Km 23.850(D8)

1 Classification SM CI

2 Particle size distributionGravel (%) 19 00Sand (%) 63 26Silt (%) 12 48Clay (%) 06 26

Fines passing 75µ sieve (%) 18 743 Cu 20.00 -

Cc 2.31 -4 Consistency limits:

Liquid Limit NP 43Plastic Limit NP 19

Plasticity Index NP 24Shrinkage limit - 18

Differential Free Swell - 205 OMC (%) 8.00 12.00

MDD (g/cm3) 2.164 1.986 California bearing ratio


1.39 3.87


1.22 7.69


0.212 0.467

Grain size distribution & test for consistency conducted on the collected soil/blanket samples classify the blanket material as SM and CI (Formation soil).

Shrinkage limit of formation soil is 18, shows soil is moderate shrinkable and very near to the borderline of high shrinkable soil.

Differential free swell index of subgrade soil is 20, which indicates that subgrade soil is not swelling in nature.

Subgrade soil contains fines upto 74% and liquid limit is 43. The PI value is 24. The soil is cohesive and having quite low MDD value. Blanket material contains fines upto 18% which is more than the stipulated value.

California bearing ratio of embankment fill material is 7.69 which is more than the stipulated value. California bearing ratio of blanket material is 1.39 which is less than the stipulated value.

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Cu value of blanket material is 20.00 is more than the stipulated value and Cc value of blanket material lies between the permissible limits. Also the blanket material does not follow the enveloping curve.

RECOMMENDATIONS:

As per lab test results, California bearing ratio of blanket material is 1.39 which is less than the stipulated value. Also blanket material contains fines upto 18% which is more than the stipulated value. As per “Guideline and Specification for Design of Formation for Heavy Axle Load” issued by RDSO report no. RDSO/2007/GE:0014, Nov 2009, minimum CBR value of blanket material should be 25 and percentage of fines passing through 75 microns should lie between 3% to 10%. Therefore, blanket material used in this location does not satisfy specification of blanket material.

As per lab test results, percentage of fines at km 23.850 is 74% and CBR value is 7.69. Therefore, this soil comes in SQ1 category. Therefore at this location, as per GE:0014, Nov 2009, single layer of 100 cm thick blanket for SQ1 (SQ1, only with dispensation of PCE/CAO) may be provided.

Considering cost aspect, SQ3/SQ2 soil can be brought for prepared subgrade and follow Para 6.0 a) of page 7. This will reduce blanket thickness. However overall economy should be seen.

As the maximum height of bank is 6m therefore, at this location slope stability analysis should be carried out using effective soil shear parameters.

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6.1.5 Km 25.00 to Km 35.00

Two disturbed soil samples were collected.

Soil Properties

SNo Soil Parameters

Ground Soilat

Km 32.375 (D5)

Subgrade Soilat

Km 32.375(D6)

1 Classification ML CI2 Particle size distribution

Gravel (%) 00 15Sand (%) 41 31Silt (%) 52 43Clay (%) 07 12

Fines passing 75µ sieve (%) 59 553 Cu 31.25 2.69

Cc 176.47 0.784 Consistency limits:

Liquid Limit NP 39Plastic Limit NP 18

Plasticity Index NP 21Shrinkage limit - 13.1




6.50 0.95


19.80 0.90


0.402 0.348

Grain size distribution & test for consistency conducted on the collected soil samples classify the soil as CI (Formation soil) and ML (Ground soil).

Shrinkage limit of formation soil is 13.1, shows soil is moderate shrinkable and very near to the borderline of high shrinkable soil.

Differential free swell index is 20 for formation soil, which indicates that formation soil is not swelling in nature.

Formation soil contains fines upto 55% and liquid limit is 39. The PI value is 21. The formation soil is cohesive and having quite low MDD value.

Undrained shear strength, Cu of ground soil is 0.402 kg/cm2, which is more than the stipulated value.

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RECOMMENDATIONS:



As per lab test results, at km 32.375 the subsoil is ML and subgrade soil is CI. As ML soil is already available as subsoil, it is not clear why CI type of soil is used for subgrade.

The maximum height of bank is 9.5m therefore, at this location slope stability analysis should be carried out using effective soil shear parameters.

6.1.6 Km 62.75 to Km 67.25/Km 17.50 to Km 22.00 (from Bishnupur side)Two disturbed soil samples were collected. Soil Properties

SNo Soil Parameters

Ground Soilat

Km 18.900(D10)

Subgrade Soilat

Km 18.900(D11)

1 Classification CI ML2 Particle size distribution

Gravel (%) 00 11Sand (%) 18 15Silt (%) 56 74Clay (%) 26 00

Fines passing 75µ sieve (%) 82 743 Cu - 8.40

Cc - 0.804 Consistency limits:

Liquid Limit 43 NPPlastic Limit 21 NP

Plasticity Index 22 NPShrinkage limit - NP




1.59 4.60


1.31 6.23


0.350 0.198

Grain size distribution & test for consistency conducted on the collected soil samples classify the soil as ML (Formation soil) and CI (Ground soil).

Differential free swell index is 20 for formation soil indicates that formation soil is not swelling in nature.

Soil contains fines upto 74% to 82%. The soil is cohesive.

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Undrained shear strength, Cu of ground soil is 0.350 kg/ cm2, which is more than the stipulated value but undrained shear strength of subgrade soil is 0.198 kg/ cm2, which is less than the stipulated value.

California bearing ratio of embankment fill material is 6.23 which is more than the stipulated value.

RECOMMENDATIONS:

As per lab test results, percentage of fines at km 18.900 is 74% and CBR value is 6.23. Therefore, this soil comes in SQ1 category. At this location, as per GE:0014, Nov 2009, single layer of 100 cm thick blanket for SQ1 (SQ1, only with dispensation of PCE/CAO) may be provided.

However, considering cost aspect, SQ3/SQ2 soil can be brought for prepared subgrade and follow Para 6.0 a) of page 7. This will reduce blanket thickness. However overall economy should be seen.

The maximum height of bank is 6m therefore, at this location slope stability analysis should be carried out using effective soil shear parameters.

6.2 AMBIKA KALNA-NABADWIP DHAM DOUBLING PROJECT :

Four disturbed sub-soil samples were collected.

Soil Properties

SNo

Soil Parameters

Ground Soilat

Km 44.10(A1)

Ground Soilat

Km 52.00(A2)

Ground Soilat

Km 56.00(A3)

Ground Soilat

Km 61.80(A4)

1 Classification CH CH CL CI

2 Particle size distributionGravel (%) 03 00 00 02Sand (%) 32 13 09 21Silt (%) 60 43 69 62Clay (%) 05 44 22 15

Fines passing 75µ sieve (%) 65 87 91 773 Cu 18.68 - - 41.43

Cc 1.07 - - 0.794 Consistency limits:

Liquid Limit 53 68 34 43Plastic Limit 27 31 21 23

Plasticity Index 26 37 13 20Shrinkage limit 15 - - -

Differential Free Swell 25 - - -5 OMC (%) 13.60 14.80 9.00 12.88

MDD (g/cm3) 1.752 1.66 1.98 1.886 California bearing ratio


2.12 2.25 2.89 -


2.34 1.87 3.60 -

7 Shear Parameters

Unconfined Compressive strength, Cu (kg/cm2)

0.638 0.806 0.743 -

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Grain size distribution & test for consistency conducted on the collected ground soil samples classify the soil as CH/CL/CI.

Shrinkage limit is 15, shows soil is moderate shrinkable and very near to the borderline of high shrinkable soil.

Differential free swell index is 25, which indicates that ground soil is not swelling in nature.

Soil contains fines upto 65% to 91% and liquid limit varying from 34% to 68%. The PI varies from 13% to 37%. The soil is cohesive and having quite low MDD value at km 44.10 and km 52.00.

Undrained shear strength, Cu of ground soil varies from 0.638 to 0.806 kg/ cm2 is more than the stipulated value.

RECOMMENDATIONS:

Undrained shear strength, Cu of ground soil varies from 0.638 to 0.806 kg/ cm2 is more than the stipulated value.

As the construction work pertaining to formation was not started and subgrade soil was not decided during visit, therefore it is not possible to predict about blanket thickness without testing of subgrade soil. When the subgrade soil is decided then as per Para 5.1.1(b) of “Guidelines for earthwork in railway projects”-July 2003, for top 3m of embankment, clays and silts of high plasticity (CH & MH) should be avoided and railway should also follow “Guideline and Specification for Design of Formation for Heavy Axle Load” issued by RDSO report no. RDSO/2007/GE:0014, November 2009, which is available at www.rdso.indianrailways.gov.in/Directorate/GeotechnicalEngineering/Geotechnicalreports.

6.3 KATWA-PATULI, DOUBLING PROJECT :

Four disturbed samples of ground soil were collected.

Soil Properties

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SNo

Soil Parameters

Ground Soilat

Km 87.90(K1)

Ground Soilat

Km 91.60(K2)

Ground Soilat

Km 97.00(K3)

Ground Soilat

Km 102.00(K4)

1 Classification CI ML CL SM

2 Particle size distributionGravel (%) 00 19 05 02Sand (%) 08 21 20 66Silt (%) 64 56 68 30Clay (%) 28 04 07 02

Fines passing 75µ sieve (%) 92 60 75 323 Cu - 10.71 16.55 5.20

Cc - 1.01 1.03 1.604 Consistency limits:

Liquid Limit 45 NP 34 NPPlastic Limit 24 NP 21 NP

Plasticity Index 21 NP 13 NPShrinkage limit - NP - NP

Differential Free Swell - - - 105 OMC (%) 10.60 10.60 10.20 10.20

MDD (g/cm3) 1.880 2.00 1.908 1.966 California bearing ratio


5.29 3.58 2.04 8.61


5.18 7.10 3.02 9.44

7 Shear Parameters

Unconfined Compressive strength, Cu (kg/cm2)

0.537 0.507 0.826 0.186

Grain size distribution & test for consistency conducted on the collected ground soil samples classify the soil as CI/ML/CL/SM.

Differential free swell index is 10 of ground soil indicates that ground soil is not swelling in nature.

Soil contains fines upto 32% to 92% and liquid limit varying from NP to 45. The PI varies from NP to 21. The soil is cohesive except at km 102.00.

Undrained shear strength, Cu of ground soils at Km 87.90, Km 91.60, and Km 97.00 are more than the stipulated value but undrained shear strength, Cu of ground soil at km 102.00 is 0.186 kg/ cm2, which is less than the stipulated value.

RECOMMENDATIONS:

Undrained shear strength, Cu of ground soils at Km 87.90, Km 91.60, and Km 97.00 are more than the stipulated value but undrained shear strength, Cu of ground soil at km 102.00 is 0.186 kg/cm2, which is less than the stipulated value. As per para 17.2 of “Guideline and Specification for Design of Formation for Heavy Axle Load” issued by RDSO report no. RDSO/2007/GE:0014, Nov 2009, this location will require ground improvement. Brief on ground improvement techniques has been given in Annexure-I of above mentioned guideline. However, details of some ground improvement techniques are available in various RDSO reports on RDSO website – www.rdso.indianrailways.gov.in/Directorate/GeotechnicalEngineering/Geotechnicalreports.

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As the construction work pertaining to formation was not started and subgrade soil was not decided during visit, therefore it is not possible to predict about blanket thickness without testing of subgrade soil. When the subgrade soil is decided then as per Para 5.1.1(b) of “Guidelines for earthwork in railway projects”-July 2003, for top 3m of embankment, clays and silts of high plasticity (CH & MH) should be avoided and railway should also follow “Guideline and Specification for Design of Formation for Heavy Axle Load” issued by RDSO report no. RDSO/2007/GE:0014, November 2009, which is available at www.rdso.indianrailways.gov.in/Directorate/GeotechnicalEngineering/Geotechnicalreports.

ACKNOWLEDGEMENTS

The report has been prepared by Geo-technical Engineering Directorate under guidance of Shri M.K.Gupta, Executive Director/B&S/RDSO and Shri Rajesh Agarwal Director/Geo-technical Engineering/RDSO.

Following officials of Geo-technical Engineering Directorate of RDSO were associated in preparation of the Consultancy Report:

1. Shri S.K. Ojha, ARE 2. Shri S.K. Goyal, SRE 3. Shri M.Maingi, SRE

4. Shri S.K.Pal, SRE

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Following officials of Geo-technical Engineering Directorate of RDSO were associated in laboratory testing:

1. Shri Nirbhay Kumar Singh, SRE2. Shri Jayant Chowdhury, SRE3. Shri D.K.Srivastava, SRE4. Shri S. D. Sharma, SRE5. Shri Bimal Kumar, JRE-I

………..

ANNEXURE-I

RECOMMENDED SPECIFICATIONS OF BLANKET MATERIAL (Mandatory)

Specifications of the material for blanket layer over prepared sub-grade should be such that it is well-graded sandy gravel layer of adequate hardness. Particles size gradation curve should be more or less within Enveloping Curves of blanket material as shown in Figure below & Grading Percentages within the range given in Table below and should also have following criteria satisfied :

i) Cu > 7 and Cc between 1 and 3. ii) Fines (passing 75 microns): 3% to 10%.iii) Los Angeles Abrasion value < 35%.iv) Minimum required Soaked CBR value 25 of the blanket material compacted at

100% of MDDIn exceptional cases on technical and economic considerations, LAA value may be relaxed up to 40% by Pr CE on Open Line & CAO/C in construction projects.

v) Filter Criteria should be satisfied with prepared subgrade/subgrade layer just below blanket layer, as given below:

Criteria–1: D15 (blanket) < 5 x D85 (sub-grade)Criteria–2: D15(blanket) > 4 to5 D15 (sub-grade)

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Criteria–3: D50(blanket) < 25 x D50 (sub-grade)

Filter Criteria is optional, at present. This can be adopted with the experienced gained of its compliance for different types of soils with blanket.

Table: Grading Percentage of Blanket Material

SL IS Sieve Size Percent Passing (by weight)1. 40 mm 1002. 20 mm 80 - 1003. 10 mm 63 - 854. 4.75 mm 42 - 685. 2 mm 27 - 526. 600 micron 13 - 357. 425 micron 10 - 328. 212 micron 6 - 229. 75 micron 3 - 10

Figure: Enveloping Curves for Blanket Material

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KAMARKU

NDU (KQ

U) (VIA CH

ORD) KM

. 32.93

TARAKESW

AR (KM. 5

7.09) KM

. 0.00

1. DOUBLING SECTIONS SHOWN AS REFERRED

AND CONSULTANCY RENDERED2. NEW CONSTRUCTION - SECTION SHOWN

AND CONSULTANCY RENDERED

LEGEND:-

KHARAGPUR (KGP) KM. 115.365

S.E. RLY.

Index Plan Showing Locations of review of blanket thickness of

Tarkeshwar-Bishnupur section, & doubling projects of Ambikakalna-

Nawadipdham & Katwa-Patuli section, Howrah Division, Eastern Railway

DRG. NO. GE/SK/ER/657/REV.0/2010NOTE:- NOT TO SCALE

HOWRAH (HWH) KM. 0.00

Research Designs & Standards Organisation

TO NAIHA

TI JN. (NH

)

TO BARDDHAMAN JN. (BWN)

KATWA JN. (KWAE) KM. 143.99

NABADWIPDHAM KM. 104.82

PATULI (PTAE) KM. 126.29

TO BARHARWA JN. (BHW)BISH

NUPUR (VS

U) KM. 84.

75

TALPUR K

M. 04.50

ARAMBAG

H KM. 24.

50MAY

ANAPUR K

M. 62.75

TO ASANS

OL JN. (A

SN)

AMBIKA KALANA(ABKA) KM. 81.53

N

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Documents

GOVERNMENT OF INDIA MINISTRY OF RAILWAYS · issued by RDSO in November 2009 came under discussion. Eastern railway requested, ... Axle Load” issued by RDSO report no. RDSO/2007/GE:0014,