Consultancy rendered to SR Two GE-CR-0146

For official use only

Consultancy Report On

Gauge conversion

Between

Villupuram- Vellore Cantt section

Tiruchchirappalli division: Southern

Railway,

nf{k.k jsyos d¢ fr:fpjkiYyh eaMy esa foYyqiqje&o¢Yy©j dSUV [k.M d¢ ¬vkeku¬ifjorZua d¢ fy, ijke'kZ vk[;k

Consultancy No. RDSO/2010/GE: CR-0146

ijke'kZ la[;k RDSO/2010/GE:CR-0146

October, 2010

vDrwcj z 2010

Geo-technical Engineering Directorate

Hkw&rduhdh bathfu;jh funs’kky; Research Designs & Standards Organisation

vuqla/kku vfHkdYi vkSj ekud laxBu Lucknow – 226011

y[kuÅ & 226011

1

PREFACE

This report is based on the basis of soil exploration, field investigation, soil testing and literature survey. The views expressed are subject to modifications from time to time in the light of future developments on the subject. The views do not represent the views of Ministry of Railways (Railway Board), Government of India.

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

2

SYNOPSIS

Gauge conversion between Villupuram-Vellore cantt section, Tiruchchirappalli

division, Southern Railway has been completed in Dec-2009. CRS inspection was carried out in March-April 2010 but not given the authority to open

the section. Sectional speed of the section is 100km/h. Presently goods

are permitted in the section since June-2010. Longitudinal cracks on cess,

erosion of slope of embankment, steeper slope, loose earth on cess and slope etc. has been reported by the railways as pointed out by CRS.

On request of Railway, RDSO carried out detailed soil investigation of the

six locations and collected soil samples from site. These undisturbed &

disturbed soil samples are tested in GE lab/RDSO.

Present Report includes proper re-profiling of slope including compaction,

provision of cross slope of 1:30 at the top of formation, pitching/turfing on finished slope etc..

3

fo"k;&lwph INDEX

dze SL

fooj.k Particulars

i`"B Page

izkDdFku Preface

1

Lkkjka’k Synopsis

2

1. izLrkouk Introduction

4

2. lanHkZ References

4

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

5

4. bfrgkl

History 5

5. jsyiFk lajpuk Track Structure

5

6. e`nk uewukas dk fooj.k Details of soil samples 6

7. {®= fujh{k.k ,oa {®=h; vkdM+®a dk ,d=hdj.k Site Inspection And Collection Of Field Data

6

8. fo'ys"k.k ,oa ijh{k.k ifj.kke®a ij fopkj foe'kZ Analysis & Discussion Of Test Results

10

9. leL;k”dkšdkj.k Causes of problem

17

10. <ky dh fLFkjrk dk fo'ys"k.k Slope Stability Analysis

17

11. laLrqfr;ka Recommendations

18

v-v-ek-l- dh Vhe Team Of RDSO

22

12. fp= Figures –

¼i½ lwph fp= Index Map (fp= 1/ Fig 1) ¼ii½ orZeku iz®Qkby Existing Profiles (Fig 2 to Fig 7)

¼iii½ laLrqra iz®Qkby Recommended Profiles (fp= 8/ Fig 8) (v) laLrqra iz®Qkby Recommended Profiles (fp= 9 Fig 9) (vi) Sandwich Construction ( Sketch F)

(vii) Slope Stability Analysis ( Annexure I &II)

23

24-29 30 31 32

33-34

4

1.0 INTRODUCTION

The Gauge conversion work from km 000.00 to km 149.58 between

stations villupuram to vellore cantt of Tiruchchirappalli Division has been

carried out by Southern Railways from Dec. 2007 to Nov. 2009. CRS,

Southern circle inspection was carried out in March-April 2010 but

authorisation for running passenger trains was not given. However goods

traffic at 60kmph are running (1-2 trains per day) since June 2010. After

CRS inspection, six problematic locations were identified by the railway

and approach RDSO for an appropriate solution for the problematic

locations.

CE/C/S.Rly letter No. W/347/XXII/II/CN dated 26.06.2006 referred six

locations of the section to RDSO for investigation & suggesting remedial

measures. Accordingly RDSO team consist of Shri S.K.Ojha, ARE/GE and

Shri Shiv Kumar, SSRE/GE visited six locations in the month of August-10

along with Railway officials Sh.Mohd.Saliya, Dy.CE/C/TBM, Sh.Sriniwas,

AXEN/CN/TBM, Sh.Ethiraj AXEN/CN/TBM, Sh Manohar, SE/W/TBM, Sh.

Gaffor, JE/W/TBM and Sh. Appavoo, SE/Work/CN,TBM to investigate and

suggest remedial measures.

The soil used in the formation in three categories:

i) The original core of MG formation was constructed about 117 year

old and made with blackish colour soil by visual examination and after testing it is classified as clayey sand.(SC Type)

ii) The soil used in the widening is radish colour coarse grained soil by

visual examination and after testing it is classified as clayey sand except one location.(SC Type)

iii) The soil used from borrow pit for repair of bank after CRS

inspection.

Vide reference this office letter No. RS/G/72-SR dated 16.07.2010,

Railway authority told that they are still doing the necessary work in

compliance of CRS note, hence RDSO team inspection postponed for 15

days. Hence the RDSO team inspection was carried out in the month of

August’ 2010. RDSO team inspected the site and collected soil samples

from these six locations. These locations are primarily bridge approaches.

2.0 REFERENCE

CE(Con.), vide his letter No. W/347/XXII/II/CN dated 26.06.2010

requested RDSO for investigating and advising remedial measures.

5

3.0 SCOPE OF WORK

Site inspection of six locations i.e. Km 135/100-200, Km 134/100-200,

Km 120/900-121/000, Km 63/550, Km 33/100-200, Km 09/000-100, Soil

sampling and testing for checking the stability of bank, assessment of

compaction and other geo-technical aspects of the above mentioned

locations and suggest suitable measures.

4.0 HISTORY This is gauge conversion project, the new BG line is almost at the

centerline of the existing old MG line except at km63/500-600 location

(Diversion portion). The old MG bank is about 117 year old made with

locally available blackish colour clayey soil which has consolidated over

the years. In this section there was no formation problem on old bank

and no speed restriction as stated by Railway officials. The earth work in

formation commenced during dec.2007 and completed during nov.2009.

CRS inspection was carried out in March-April 2010 but the authority to open the section were not given. However goods traffic at 60kmph (1-2

trains per day) were permitted by zonal railway and goods trains are running since June 2010. Maximum height of the bank is 5.7 m at

km.63/550 among the 6 locations inspected. Index map showing all the six locations placed at Fig.1. As per discussion during inspection with

railway authorities, following deficiencies brought out as under:

1. No benching and compaction was done during earthwork (widening). 2. No sand layer was provided in the widened portion as per para 6.7

(Sketch F) of Guidelines of Earth work in Railway Projects, GE:G-1, July’ 2003.

3. Formation width 7-8m is provided during construction. No field lab was

provided during construction.

4. All the testing had been carried out from private institutions. No slope

stability analysis had been carried out but 2:1 slope provided.

5.0 TRACK STRUCTURE

Km 0 to 149

Rail : 52Kg, LWR/SWR laid during 2008-10

Sleeper : PSC laid during 2008-10

Sleeper Density : 1540

GMT : 0.61 to 1.06 (MG) Yet to assessed on new BG track

Ballast cushion : 300 mm

Condition of Track

: Good

6

6.0 DETAILS OF SOIL SAMPLES

Fourteen numbers of Disturbed/Undisturbed soil samples were collected

from the locations given in Table-I

Table-I

SL Location Disturbed Undisturbed Total Figure

1 Km 135/100-

200

1 1 2 2

2 Km 134/100-

200

1 1 2 3

3 Km 120/900-

121/000

3 - 3 4

4 Km 63/550 3 1 4 5

5 Km 33/100-200 1 - 1 6

6 Km 09/000-100 2 - 2 7

These soil samples were tested in Geo-technical Engineering Laboratory

at RDSO for the following tests:

• Natural Moisture Content (NMC)

• Natural Dry Density (NDD)

• Grain Size Analysis

• OMC & MDD

• Differential free swelling index (DFS)

• Triaxial shear test in Consolidated Undrained condition with measurement of pore pressure (CU)

• California Bearing Ratio (CBR)

7.0 SITE INSPECTION OBSERVATIONS

7.1 Km.135/100-200 (Bridge No 371)

• Earth dumped for profiling of slope & cess is not properly

compacted.

• Presently no cracks are visible on cess. Cracks were not visible

due to earth filling on cess & slope. Cess is high on LHS (facing

Vellore).

• To stabilise the bank, RCC retaining wall constructed between

km 135/350-133/500 (approx 2.8km) on LHS (facing Vellore).

Height of retaining wall = 2m above GL. This will have stabilising effect.

• Borrow pits of 1.5m depth & 3m wide at the distance of about 2m from the toe of the bank have been observed near the toe

of bank at km 135/100-200.

7

• Rain cuts observed near km 135/200.

• On RHS side slope is not properly dressed. • Boulders are also seen in the soil dumped for profiling and are

to be removed.

• Formation width = 7.0m, Side slope(LHS) = 2.12:1, Cess width

= 90cm-1.0m. • One UDS & one DS soil sample collected for testing (Fig. 2).

• Final profiling is done with radish colour clayey soil. After testing

soil is reported as clayey sand.

Km.135/100-200 Km.135/100-200

7.2 km. 134/000-100 (Bridge no 366)

• As per CE letter no. W.347/XXII/11/CN dated: 25.06.2010 it is

mentioned that Cracks was visible on the cess and as per D.O. letter W.347/XXII/11/CN dated: 29.07.2010, the all works in six locations has been completed. During inspection, no cracks was visible as earth is filled on cess/slope.

• Earth work on slope is loose on LHS & RHS and to be compacted Cess is high on LHS but low on RHS side.

• RCC retaining wall on LHS of 2m high above GL has been constructed after CRS inspection at the toe of the bank.

• Slope made 2:1 above retaining wall. • Water is flowing from LHS to RHS. • Rain cuts are seen at some places on bank slope on RHS. • Formation width is 7.15 m and side slope 2.25:1, • Two samples (one UDS & one DS) have been collected for testing. • Locally available radish colour clayey soil used for subsequent bank

profiling. • No turfing is provided.

8

km. 134/000-100 km. 134/000-100

7.3 Km.120/900- 121/000 ( Bridge no. 315 )

• No cracks are visible as soil filled on cess. • Retaining wall provided in 60m length on all four sides of the bridge after

CRS inspection. Above retaining wall 2:1 side slope is provided. On slope CC block pitching is in progress in 60m length on all four sides.

• As this is major bridge and high variation in alignment and surface unevenness, hence ballast wall is 20m length and 65 cm high on all four sides are constructed. Ballast is to be filled up between ballast retainers.

• Two density checks to assess the degree of compaction has been carried out and found field dry density as 1.59 and 1.71 gm/cc.

• Soil used for repair is radish clayey not compacted. • Final reading of track parameter after ballast filling is required. • Formation width = 7.8m, cess width = 1.0m, side slope (RHS) = 2.17:1. • Three disturbed soil samples have been collected for testing.

Km.120/900- 121/000 Km.120/900- 121/000

9

7.4 Km.63/550 (Diversion portion)

• A borrow pit (4m wide & 1m deep) at the distance of 3m from the toe

of the bank is seen all along at km 63/400-63/700 (RHS). Retaining wall is provided along the bank.

• Soil for slope and cess repair is not compacted. • RCC retaining wall constructed between Km 63/400-64/000 which

was designed by Railway itself. • Rain cuts observed on cess & slope between km 63/500-600 due to

non compaction. Cess is high on RHS. • Still settlement cracks are visible on cess & slope on LHS. • Soil used for cess repair near km 63/400 is local fine grained soil. • Face wall is required on LHS of bridge. • Retaining wall is required between km 63/400-600 (LHS) where MG

bank was not adjacent to new B.G. bank. • Four soil samples (one UDS & three DS) are collected for testing. • Formation width = 8.8m, cess width= 1.5-2.0m, side slope (LHS)=

1.941:1. Height of bank is 5.7m.

Km.63/550 Km.63/550

7.5 Km. 33/100-200 (Bridge no. 78)

• It is yard portion. • Slope is not properly dressed. • Cess is uneven and not properly leveled. • Rain cuts observed at number of places between km33/150-200

(RHS). • Railway affecting tank is situated 10m away from the embankment. • RCC retaining wall constructed between km33/350-32/975 (On

tank side i.e.,LHS) and km.31/100-32/940 (RHS). • Pitching is to be done on all four sides of bridge. • Soil on cess and slope is radish colour fine grained soil is to be

removed. • One disturbed soil sample taken for testing. • C/C of track 5.5-5.7m and side slope (LHS)= 2.12:1.

10

Km. 33/100-200 Km. 33/100-200

7.6 Km.9/000-100 Bridge no 24

• Existing old MG bank was 7m wide but railway has widened the

bank to 10m formation width with radish colour clayey soil. • Bank height is 0.6m. • Guide wall and face walls are to be made on bridge • Two soil samples (one for existing old MG bank and one for filling

material) are taken for testing. • M/s COS consultant soil tests result is not verified with the soil used

for widening as well as old MG bank. • Side slope is 2:1.formation width is 10m.

Km.9/000-100 Km.9/000-100

8.0 Analysis & Discussion of Test Results

8.1 Location km 135/180

One undisturbed soil sample and one disturbed soil sample collected from

this location were tested & test results are as under:

11

Soil Properties

S.No. Soil Parameters Formation Soil

Disturbed (D1)

Formation Soil

Undisturbed

(UDS1) 1. Classification SC SC

Grain size distribution

Gravel (%) 10.28 6.06

Sand (%) 56.82 45.32

Silt (%) 31.98 41.74

Clay (%) 0.92 6.88

Fines passing 75µ sieve (%)

32.9 48.62

3. Consistency Limits:

Liquid Limit 41 40

Plastic Limit 23 22

Plasticity Index 18 18

Specific Gravity 2.15 --

4. OMC(%) 10.00 --

MDD(g/cm3) 2.02 --

NMC -- 16.21

NDD -- 1.847

5. Cu 41.82 62.50

Cc 1.02 3.91

6. Shear parameters:

C′(kg/cm2) -- 0.053

φ′ (degree) -- 31.19

� Grain size distribution & test for consistency conducted on the collected soil samples classify the soil as SC (Formation soil) i.e. sandy clay and it is suitable for bank formation.

� However looking the Liquid Limit around 40%, Plasticity index is 18%, Plastic Limit around 23% and fines in the soil around 49%, the bank will require more maintenance efforts for some time. .

� Shear strength parameter (C′, φ′) were determined for slope stability analysis.

� Natural Dry Density of the soil is 1.847 gm/cc and MDD as 2.02 gm/cc gives

91.4% degree of compaction. It is seen that degree of compaction at site is less than the desired value which may adversely affect the strength of formation.

8.2 Location Km. 134/075

One undisturbed soil sample & one disturbed soil sample collected from this

location were tested & test results are as under:

12

Soil Properties

S.No. Soil

Parameters

Formati

on Soil

(D2)

Formation Soil

(UDS2)

1. Classification SC SC

2. Grain size distribution:

Gravel (%) 21.36 18.30

Sand (%) 57.08 55.06

Silt (%) 21.28 23.89

Clay (%) 0.28 2.75

Fines passing

75µ sieve (%)

21.56 26.64


Liquid Limit 42 40

Plastic Limit 25 24


4. OMC(%) 7.88 --

MDD(g/cm3) 2.07 --

NMC -- 11.08

NDD -- 1.944

5. Cu 94.74 78.57

Cc 1.42 0.65


C′(kg/cm2) -- 0.035

φ′ (degree) -- 33.22

� Grain size distribution & test for consistency conducted on the collected soil samples classify the soil as SC (Formation soil) i.e. sandy clay.

� However looking the Liquid Limit around 42%, Plasticity index is 17%, Plastic Limit around 25% and fines in the soil around 27%, the bank will require more maintenance efforts for some time.

� Natural Dry Density of the soil is 1.944 gm/cc and MDD as 2.073 gm/cc gives

93.7% degree of compaction. It is seen that degree of compaction at site is less than the desired value which may adversely affect the degree of compaction.


One disturbed soil sample collected from this location was tested & test results are as under:

13

Soil Properties

S.No. Soil

Parameters Formation Soil (D3)

1. Classification SC

2. Grain size Distribution:

Gravel (%) 20.04

Sand (%) 58.60

Silt (%) 21.36

Clay (%) 00.00


21.36


Liquid Limit 40

Plastic Limit 25

Plasticity Index 15

4. OMC(%) 7.55

MDD(g/cm3) 2.125

5. Cu 45.00

Cc 0.67

� Grain size distribution & test for consistency conducted on the collected soil

samples classify the soil as SC (Formation soil) i.e. sandy clay.

� However looking the Liquid Limit is 40%, Plasticity index is 15%, Plastic Limit is 25% and fines in the soil around 21%, the bank will require more maintenance efforts for some time. .

� Field dry density is 1.587 gm/cc of top of formation soil and MDD as determined in RDSO’s GE-Lab is 2.125 gm/cc. Therefore, degree of compaction comes out as 74.7% which shows less compaction at this location. Since degree of compaction is less than the desired limit which adversely affects the strength of formation


Two disturbed soil samples collected from this location were tested & test results are as under:

14

Soil Properties

S.No.

Soil

Parameters

Formation

Soil (D4)

Formation Soil

(D5) 1. Classificati

on SW-SC SC


Gravel (%) 20.50 2.92

Sand (%) 70.88 74.36

Silt (%) 8.62 22.26

Clay (%) 00.00 0.46


8.62 22.72


Liquid Limit 31 41

Plastic Limit 18 23

Plasticity Index

13 18

4. OMC(%) 8.15 7.93

MDD(gm/cm3)

2.12 2.08

5. Cu 22.35 46.67

Cc 1.55 1.61

� The soil, which is being used in the existing embankment, classifies as SW-SC and SC (Formation soil) i.e. well graded sand with sandy clay and sandy clay.

� However looking the Liquid Limit around 41%, Plasticity index around 18%, Plastic Limit around 23% and fines in the soil around 23%, the bank will require more maintenance efforts for some time. .

� Field dry density is 1.709 gm/cc of top of formation soil and MDD as determined in RDSO’s GE-Lab is 2.12 gm/cc for top of formation soil. Therefore, degree of compaction comes out as 80.61% which shows less compaction at this location. Since degree of compaction is less than the desired limit which adversely affects the strength of formation


Two undisturbed soil samples collected from this location were tested & test results are as under:

15

Soil Properties

S.No. Soil Parameters

Ground

Soil

(D6)

Ground

Soil

(UDS3)

Formation

Soil

(D7)

Formation

Soil

(D8) 1. Classification SM SM SC SC


Gravel (%) 0.54 00 5.37 11.89

Sand (%) 69.85 64.91 70.31 69.57

Silt (%) 27.54 31.88 22.70 18.08

Clay (%) 2.07 3.25 1.62 0.46


29.61 35.09 24.32 18.54


Liquid Limit NP NP 28 31

Plastic Limit NP NP 17 19

Plasticity Index NP NP 11 12

Specific Gravity -- -- 2.47 --

Shrinkage Limit -- NP -- --

Differential Free Swell

-- 10 -- --

4. OMC(%) 7.00 -- 8.50 7.20

MDD(g/cm3) 2.12 -- 2.17 2.15

NMC -- 4.88 -- --

NDD -- 1.601 -- --

5. Cu 22.50 28.38 50.83 37.50

Cc 1.74 3.34 1.65 1.60


C′(kg/cm2) -- 0.01 -- --

φ′ (degree) -- 35.15 -- --

� Grain size distribution & test for consistency conducted on the collected soil samples classify the soil as SM (Ground soil) i.e. Silty sand and the soil as SC (Formation soil) i.e. sandy clay. The ground soil is a silty sand and formation

soil is sandy clay, which come under the category of coarse grained soil.


� Shear strength parameter (C′, φ′) were determined for slope stability analysis


One number of disturbed soil sample collected from this location was tested & test results are as under:

16

Soil Properties

S.No. Soil Parameters Formation

Soil (D9)

1. Classification SC 2. Grain size distribution

Gravel (%) 7.34

Sand (%) 79.87

Silt (%) 12.79

Clay (%) 00.00


12.79


Liquid Limit 31

Plastic Limit 17

Plasticity Index 14

4. OMC(%) 7.00

MDD(g/cm3) 2.13

5. Cu 22.86

Cc 2.90



� However looking the Liquid Limit is 31%, Plasticity index is 14%, Plastic Limit around 17% and fines in the soil is 13%, the bank will require more maintenance efforts for some time. .

8.7 Location Km 9/050

One number of undisturbed soil sample collected from this location was tested & test results are as under:

Soil Properties

S.No. Soil Parameters Formation BG

Soil (D10)

Formation MG

Soil (D11) 1. Classification SC SC 2. Grain size distribution:

Gravel (%) 9.96 5.11

Sand (%) 53.19 57.96

Silt (%) 33.41 19.06

Clay (%) 3.44 17.87


36.85 36.93

17


Liquid Limit 34 33

Plastic Limit 18 17


Shrinkage Limit - 14

Differential Free Swell - 40

4. OMC(%) 10.5 8.5

MDD(g/cm3) 2.07 2.07

5. Cu 97.14 -

Cc 1.03 -




� Shrinkage limit is 14 indicate that soil is moderate shrinkable. Therefore

shrinkage cracks may form on drying.

� Differential free swell is 40 indicate that soil is moderate swelling.

9.0 CAUSES OF DEVELOPMENT OF LONGITUDINAL CRACKS

Following aspects facilitates development of cracks on top of formation:

� RDSO lab test results shows varied degree of compaction values from 74.6% to 93.7% which are below than the stipulated value (95% in case of gauge conversion).

� Under gauge conversion project during widening of bank perhaps proper benching had not been carried out as stated by railway officials and this has resulted into improper bonding between fill material of top of formation and old bank.

� At km. 9/050, Shrinkage limit as determined in the lab reported as 14 and shrinkable in nature, crack will develop when soil shrink and create problem. Differential free swell index varies up to 40% for formation and ground soil indicates that formation and ground soil is moderate swelling in nature and create problem.

� No sand layer (Sandwich construction, Fig. F) has been provided during widening of embankment as stated by railway officials; pore pressure from the soil has not dissipated in early period. Resulted into shrinkage cracks in the formation.

10.0 SLOPE STABILITY ANALYSIS

Slope stability analysis for designing side slope has been carried out with the help of Slope-W software for Ch. 63/550 where height of embankment is 5.70m and at km 135/180 where height of embankment is 5.05 m. (Cross section placed at figure3&5). The following assumptions have been made during analysis:-

18

i) Pore water pressure ratio (ru) assumed- 0.25 (formation soil) & 0.35

(sub-soil) ii) Depth factor (Df) – 1.5 With above assumptions at km 63/550, for height of embankment 5.70m and side slope of 2.25:1, the factor of safety works out to be 1.428 and at km 135/180, height of embankment 5.05m and side slope of 2.0:1, the factor of safety works out to be 1.434 which is more than minimum required factor of safety i.e. 1.4 as per Para – 2.1 of Annexure-III of “Guidelines For Earthwork In Railway Projects”, July 2003, hence safe. Slope stability analysis is attached as Annexure-I & II, based on Slope-W analysis output sheet.

11.0 RECOMMENDATIONS

Based on details of site inspection of six problematic stretches and test results of

soil samples, the following recommendations are made for all the six locations:

1. Slope stability analysis has been carried out with effective shear parameter.

2.25H:1V side slope is found safe for bank height more than 5.0m and 2H:1V

side slope for bank height less than 5.0m. Railway should provide slope

accordingly. The slope should be from top of retaining wall/toe wall where ever

provided. If side slope will not be provided as per the designed value,

embankment may fail in service.

2. Repair and re-profiling should be done with good soil duly compacted up to

95% of MDD value otherwise it will need for maintenence.

3. Erosion control measures such as turfing/ pitching should be providing on the

re-profiled side slope of the embankment.

4. Minimum formation width of 6.85m with sufficient cess width (not less than

90cm) should be ensured. Low/high cess should be properly dressed.

5. All borrow pits near to the toe of the embankment should be properly filled up

duly compacted up to 95% of MDD value where ever retaining wall is not

provided.

6. Cracks developed in formation should be properly filled with sand and sealed

with non expansive cohesive soil.

7. Rain cuts should be properly repaired.

8. Compaction of earth work varies from 74.6% to 93.7% which are below than the stipulated value (95% in case of gauge conversion) results settlement in the formation. Since compaction of the embankment may not feasible at this stage, hence Railway have to watch the behaviour of the embankment for one or two years by monitoring on the following points-

• Settlement by providing settlement platform.

• Monitoring track parameters such as regular recording of track parameters, variation in cross level and undulation of the track.

19

• Monitoring of track attention from gang chart.

• Check of any heaving of soil between sleepers, heaving/lower of cess and cracks on cess.

In addition to above following recommendations are made location wise:

i) Km 135/100-200

1. As per slope stability analysis 2H:1V side slope is safe up to 5m height of

embankment. If existing slope is flatter than 2H:1V in the section, then flatter

slope should be properly dressed and duly compacted upto 95% of MDD value

as height of bank is 5.0m.

2. Boulders used in the embankment during widening of the bank should be

removed between km 135/100-200.

3. Cracks developed in formation should be properly filled with sand and sealed

with non expansive soil.


5. Borrow pits near to the toe of the embankment should be properly filled up duly

compacted up to 95% of MDD value.

6. All loose earth dumped on side slope of the embankment should be properly


ii) Km 134/100-200








4. Erosion control measures should be providing on the re-profiled side slope of the

embankment.

5. Low cess has been observed on RHS and high cess on LHS during inspection

near km 134/100. It should be properly dressed.

iii) Km 120/900-121/000





2. As stated by railway officials pitching will be done with CC blocks, hence pitching

with CC blocks should be done on all four sides slopes of the bridge near km

120/900.

20

3. Ballast should be filled between ballast retainers on approaches of bridge near

120/900. Final reading of track parameters should be taken after ballast filling

and verified.




embankment

iv) Km 63/550

1. Bank re-profiling should be carried out with 2.25H:1V side slope duly compacted

upto 95% of MDD value as height of bank is 5.7m.

2. Protective RCC retaining wall is to be constructed on LHS between km 63/400-

63/600 (200m length) where existing MG bank is not adjacent to newly

constructed BG bank.

3. Face wall is required on LHS of bridge near km 63/550.

4. So many organic matters, boulders present in the soil used for slope repair near

km 63/550. All these should be removed. B.C. soil has also been used for slope

repair. Bad soil should be removed and replaced with good soil. Soil should be

properly compacted. Low cess should be properly dressed.



embankment.

7. Borrow pits near to the toe of the embankment should be properly filled up duly


8. Cracks have been observed on the cess and side slope. These should be properly

filled with sand and sealed with non expansive soil.

v) Km 33/100-200



slope should be properly dressed and duly compacted up to 95% of MDD value


2. As stated by railway officials will be done with CC blocks hence pitching with CC

blocks should be done on all four side slopes of the bridge near km 33/100.


embankment.

vi) Km 9/000-100

1. As bank height is less than 1m and widening of embankment was under

progress, widening should be done with 2H:1V side slope duly compacted up to

95% of MDD value.

21

2. As per RDSO lab test results soil used in MG bank is SC type i.e. clayey sand

and soil used in bank widening is also SC type.

3. Guide wall and face wall are to be made on bridge no.24 near km 9/000-100.

4. Erosion control measures should adopted on the finished slope.

Special attention on all six locations

As stated by railway officials (AXEN/C/TBM) the crack on cess have been filled

with good soil. During inspection these cracks are not visible as earth dumped

on cess for repair purpose. If cracks were not properly repaired, then water

seeps into the cracks during monsoon and formation becomes unstable.

Moreover, compaction, benching and sandwich construction have not been

adopted during the widening of the embankment, these cracks (tension cracks)

may be the point of formation of slope failure. Hence as a safety point of view,

railway have to watch the track for one to two years by monitoring the

embankment, Monitoring track such as regular recording of track parameters,

variation in cross level and undulation of the track, monitoring of track

attention from gang chart, check the heaving of soil between sleepers,

heaving/lower of cess and cracks on cess. If cracks appear, immediately

properly filled with sand and sealed with non expansive soil.

Tension Cracks

Tension cracks are usually present in all slopes affected by instability. These are

produced due to the strains caused by the incipient mass movements and are

thus indicators of impending instability. These open cracks serve as a direct

path for the infiltration of surface run of water, enabling it to reach deep into the

slope mass, thereby further decreasing the factor of safety of the slope.

In addition to diverting surface water away from open tension cracks, it is

advisable to prevent water from entering the cracks by sealing them with a

flexible impermeable material such as clay. When the crack is more than a few

inches wide, it should be filled with gravel before locking with the flexible seal is

placed. The purpose of this fill is not to allow any water, which does find its way

into the crack to flow out again as freely as possible. Under any circumstances

the crack should not be filled with concrete or grout. The top layer should be

finished in such a manner that the original shape / gradient of the slope are

retained to the maximum possible expert. The filled up surface over the tension

crack should then be made waterproof.

------------------------------------

22

OFFICERS AND STAFF ASSOCIATED WITH PREPARATION OF REPORT

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 were associated in preparation of the Consultancy Report :

1. Shri S.K.Ojha, ARE 2. Shri Shiv kumar, SSRE 3. Shri Anil Ram, JRE-II

4. Shri Sushil Kumar, JE-I

Following officials of Geo-technical Engineering Directorate of RDSO were associated in soil exploration, testing and slope stability analysis:

1. Shri Nirbhay Kumar Singh, SRE

2. Shri Jayant Chowdhury, SRE 3. Shri D.K.Srivastava, SRE 4. Shri S. D. Sharma, SRE 5. Shri Bimal Kumar, JRE-I

23

ADICHCHANUR KM. 42.14

TO

PO

ND

ICH

ER

Y

KM. 09/000-100

TO

TIR

UCH

CH

IRAPPALLI

VENKATESAPURAM KM. 08.03

TELI KM. 12.03

TIRUKKOVILUR KM. 33.56

Index Plan Showing Locations of

Gauge conversion between

Villupuram-Vellore Cantonment

section, Tiruchchirappalli

Division, Southern Railway

DRG. NO. GE/SK/SR/647/REV.0/2010NOTE:- NOT TO SCALE

TO THANJAVUR

Research Designs & Standards Organisation

KM. 33/100-200

TANDARAI KM. 50.57

TIRUVAMMAMALAI KM. 67.28

KANNAMANGALAM KM. 129.47

KANIYAMBADI KM. 138.36

TO TRIVENDRAM

VELLORE CANTONMENT KM. 149.98

TO CHENNAI

VILLUPURAM JN. KM. 0.00

KM. 63/500-600

KM. 120/900-121/000

KM. 134/100-200

SEDARAMPATTU KM. 120.26

KM. 135/100-200

NKATPADI JN.

24

2. UD AND D INDICATES UNDISTURBED & DISTURBED SOIL SAMPLE RESPECTIVELY.

Cross section at Km. 135/150 (Facing Vellore)

RCC RETAINING WALL

1. ALL DIMENSIONS ARE IN mm.

NOTES:

G. L.

1850

300

3200

200

2.12:1 (Average Slope)

UD1

D1

10700

16000

Recommended profile of gauge

conversion between Villupuram &

Vellore Cantonment of

Tiruchchirapalli Division on

Southern Railway

DRG. NO. GE/SK/SR/651/Rev.0/2010


NOT TO SCALE

2.0:1(Average Slope)

C

3900

L

4900

6900

1000G. L.

Figure 2

25


Cross section at Km. 134/150 (Facing Vellore)300


NOTES:

G. L.

2900

200 2.25:1 (Average Slope)

RCC RETAINING WALL

2000

D2

UD2

9100

12400





Southern Railway



NOT TO SCALE


35004600

L C

7500

G. L.

1800

Figure 3

26

L


2. D INDICATE DISTURBED SOIL SAMPLE.

300


NOTES:

G. L.

200

2000

2000

C

9460

RCC RETAINING WALL


750

D3

4460

620

2500

1500

RCC RETAINING WALL







Southern Railway

NOT TO SCALE

300

G. L.

2000

200

D4

2440

1540

4000

620 720

9200


D5

2400

Figure 4

27


4700



NOTES:

G. L.

1.70:1 (Ave

rage

Slop

e)

5700

570

13800

500

D7

1700

4100

2400

2000

2600

L C

5000G. L.





Southern Railway



NOT TO SCALE

2000

300

D6

UD3

2000

RCC RETAINING WALL


480 610

D8

13800

2000

200

2400

Figure 5

28


G. L.



NOTES:

300

RCC RETAINING WALL

5500

2.12:1 (Avera

ge Slope)

2000

2450

200

4500 5400

CL CL

2000





Southern Railway



NOT TO SCALE

300

G. L.

RCC RETAINING WALL

40005700

CL

D9


7200

3100

200

Figure 6

29

10.0 m

L C

Cross section at Km. 9/000-100 (Facing Vellore)

(From MG)



NOTES:

G. L. 630 2:1

D11





Southern Railway



NOT TO SCALE

(From BG)

D102:1

G. L.580

Figure 7

30

FORMATION WIDTH = 6850 (MINIMUM)

Typical Recommended Profile(Bank Height Is More Than 5.0m)

2. RECOMMENDED PROFILE IS SHOWN IN RED.


NOTES:

G. L.

30cm THICK LAYERS OFLOCAL GRANULAR MATERIAL

2.25:1 (Proposed design Slope)

H>50001 IN 30

MINIMUM CESS = 900

1 IN 30

1 IN 30

1 IN 30

4880 (MG)

L C





Southern Railway



NOT TO SCALE

5000

BORROW PIT

2000

G. L.

H>5000

EXISTING PROFILE (MG)2.25:1 (Proposed design Slope)

BENCHING

MINIMUM CESS = 900

'X'FILLED UP WITH GOODSOIL DULY COMPACTED

Figure 8

31

FORMATION WIDTH = 6850 (MINIMUM)

Typical Recommended Profile(Bank Height Is Less Than 5.0m)

2. RECOMMENDED PROFILE IS SHOWN IN RED.


NOTES:

G. L.

30cm THICK LAYERS OFLOCAL GRANULAR MATERIAL

2:1 (Proposed design Slope)

H<5000

MINIMUM CESS = 900

1 IN 30

1 IN 30 1 IN 30

4880 (MG)

L C





Southern Railway



NOT TO SCALE

5000

BORROW PIT

G. L.

2000

EXISTING PROFILE (MG)2:1 (Proposed design Slope)

BENCHING

MINIMUM CESS = 900

'X' H<5000

FILLED UP WITH GOODSOIL DULY COMPACTED

Figure 9

33

ANNEXURE –I

Slope 2.25:1

Project: Gauge Conversion Between Villupuram-Vellore Cantonment SectionLocation: Km 63/550

Height = 5.7 mSlope 2.25:1Factor of safety = 1.428

Embankment Soil

Sub Soil

Bed Rock

Soil 1Embankment SoilSoil Model Mohr-CoulombUnit Weight 21.8Cohesion 3.5Phi 33.22Unsaturated Phi B 0Piezometric Line # 0Ru (added) 0.25Pore-Air Pressure 0

Soil 2Sub SoilSoil Model Mohr-CoulombUnit Weight 19.5Cohesion 1Phi 35.15Unsaturated Phi B 0Piezometric Line # 0Ru (added) 0.25Pore-Air Pressure 0

Soil 3BedrockSoil Model BedrockUnit Weight -1Piezometric Line # 0Ru (added) 0Pore-Air Pressure 0

Horizontal Distance (m)

3 5 7 9 11 13 15 17 19 21 23 25 27 29 31

Elevation (m)

2

3

4

5

6

7

8

9

10

11

12

13

14

34

ANNEXURE –II

Slope 2:1

Project: Gauge Conversion Between Villupuram-Vellore Cantonment sectionLocation: Km 135/180Height = 5.05 mSlope 2:1Factor of safety = 1.434

Embankment

Sub Soil

Bed Rock

Soil 1Embankment SoilSoil Model Mohr-CoulombUnit Weight 21.81Cohesion 5.3Phi 31.19Unsaturated Phi B 0Piezometric Line # 0Ru (added) 0.25Pore-Air Pressure 0

Soil 2Sub SoilSoil Model Mohr-CoulombUnit Weight 19.5Cohesion 1Phi 35.15Unsaturated Phi B 0Piezometric Line # 0Ru (added) 0.25Pore-Air Pressure 0

Soil 3BedrockSoil Model BedrockUnit Weight -1Piezometric Line # 0Ru (added) 0Pore-Air Pressure 0

Horizontal Distance (m)

3 5 7 9 11 13 15 17 19 21 23 25 27 29 31

Elevation (m)

2

3

4

5

6

7

8

9

10

11

12

13

14

Consultancy rendered to SR Two GE-CR-0146

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