SS Seehra Black Cotton Soil Areas Final

8/9/2019 SS Seehra Black Cotton Soil Areas Final

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GROUND IMPROVEMENT TECHNIQUIESFOR HIGHWAY CONSTRUCTION

IN BLACK COTTON SOIL AREAS :A Case Histo !

B!B!

D " S" S" See# aD " S" S" See# a

A$$itio%a& Di e'to (Hi)#*a!s+A$$itio%a& Di e'to (Hi)#*a!s+

I%te 'o%ti%e%ta& Co%s,&ta%ts a%$ Te'#%o' ats P-t" Lt$".I%te 'o%ti%e%ta& Co%s,&ta%ts a%$ Te'#%o' ats P-t" Lt$".Ne* De&#i / 001 102Ne* De&#i / 001 102

33

(Fo 4e Di e'to / G a$e S'ie%tist 3 Hea$.(Fo 4e Di e'to / G a$e S'ie%tist 3 Hea$.Ri)i$ Pa-e4e%ts Di-isio%. CRRI. Ne* De&#i+Ri)i$ Pa-e4e%ts Di-isio%. CRRI. Ne* De&#i+

I%te 'o%ti%e%ta& Co%s,&ta%ts a%$ Te'#%o' ats P-t" Lt$". Ne* De&#i



I%t o$,'tio%W#at a e B&a'5 Cotto% (BC+ Soi&s6

BC soils are inorganic clays of medium to high compressibility and forma major soil group in India (20% of the total area of India)

These soils are characterised by high shrinkage and s elling properties

!oad construction in BC soils has been a challenge to the "igh ay#ngineers

BC soil is $ery hard hen dry but loses its strength completely hen inet condition

&n drying the BC soil de$elops cracks ('ig )

*s a result of etting and drying process $ertical mo$ement takesplace in the BC soil mass

This $ertical mo$ement leads to failure of high ay pa$ement in the formof settlement hea$y depression cracking and une$enness etc



Fi)"0: C a'5s i% BC Soi& o% D ! State



B&a'5 Cotto% Soi&: Pe',&ia C#a a'te isti's

BC soil is a highly clayey soil

It is so hard that the clods cannot be easily pul$erised

The black colour in BC soil is due to the presence of Titanium &+idein small concentration

"igh percentage of clay is predominantly montmorillonite instructure

BC soil forms a $ery poor foundation material for road construction

CB! $alues of BC soils are found in the range of ,2%

-ue to $ery lo CB! $alues of BC soil e+cessi$e crust thickness isre.uired for road pa$ements

The engineering properties of BC soil (Table )/



Ta7&e 0: P#!si'a& P o8e ties o9 BC Soi&



P o7&e4s o9 Hi)#*a!Co%st ,'tio% i% BC Soi& A eas

It is a ell kno n fact that ater is the orst enemy ofroad pa$ement particularly in e+pansi$e soil areas

ater penetrates into the road pa$ement from threesides i e Top surface side berms and from subgradedue to capillary action

1teps must be taken that road surface must beimper$ious side berms pa$ed and subgrade ell

treated to check capillary rise of aterFi)" sho s de$elopment of alligator cracks inBituminous pa$ements in BC 1oil areas



Fi)" : A&&i)ato C a'5s i% Bit,4i%o,s

Pa-e4e%ts i% BC Soi& A eas



G o,%$ I48 o-e4e%t Te'#%o&o)ies 9oI48 o-i%) CBR o9 BC Soi&s

The materials for BC soil stabilisation comprise limeor &rdinary 5ortland Cement (&5C) 67 grademoorum of appro$ed .uality sand and Cohesi$e8on,s elling 1oil (C81)

Cement or hydrated lime in the range of 7,9% bringsremarkable impro$ement in the engineeringcharacteristics of BC soils

:se of ;eote+tiles 3 ;eofabrics 3 ;eogridsTa7&e indicates the impro$ement in the BC soilcharacteristics



Ta7&e : I48 o-e4e%t i% BC Soi&C#a a'te isti's *it# Li4e Ce4e%t



Use o9 Geo;te<ti&es = Geo;) i$s = Geo;9a7 i's9o G o,%$ I48 o-e4e%t

This techni.ue has tremendous potential for its application inBC soil areas

;eote+tile layer acts as a reinforcing layer and is used tocombat reflecti$e cracking in the pa$ement structure

*lso thickness reduction of pa$ement from 0 to 29%

The cost of ;eote+tiles is the stumbling factor for its iderapplication in India

"o e$er in special areas such as BC soil areas ;eo,te+tilesoffer a $iable solution to high ay engineering problems(Fi)" >. ? a%$ @ use of ;eo,te+tiles)



Fi)" >: Geo) i$s 9 o4 Ne* Po&!4e s



Fi)" ?: As8#a&t Rei%9o 'e4e%t *it# Geo;Te<ti&es



Case;Histo ies o9 Hi)#*a!Co%st ,'tio% i% BC Soi& A eas

'our <aning of 8ational "igh ay,6 (8",6) passing through BC1oil *reas

8",6 is one of the four arms of 8ational "igh ay 8et orkpopularly kno n as ;olden =uadrilateral ha$ing length ofabout >000 km as a component of 8ational "igh ay-e$elopment 5roject (8"-5)

idening of the e+isting 2,lane stretch passing through BC 1oilarea from 1atara (km ?29 00) to @aharashtra 1tate Border1ection of 8",6 (km 9A2 260) to 6,lane di$ided carriage ayand strengthening of the e+isting 2,lane section on B&T basisConstruction of Bombay,5une #+press ay passing through BC1oil *rea from 5une end (1ection -)



Co%st ,'tio% o9 Ne* ; &a%e Ce4e%t Co%' etePa-e4e%t (Ri)i$ Pa-e4e%t+ Ca ia)e*a! (NH;?+

The BC soil deposits e+isting on the road alignment ere carefullyreplaced ith C81 soil ha$ing 5I $alue ranging bet een 9 to 9 and1 elling Inde+ (1I) ranging bet een ? to 79 in the entire length of thene carriage ay

1ince the good .uality C81 soil (@oorum) as readily a$ailable inabundance from the nearby moorum .uarries along the e+istingcarriage ay hence no BC soil stabilisation as re.uired

Fi)" 2 a%$ sho compaction of C81 soil (moorum) for the ne2,lane carriage ay

Fi)" sho s compaction of -ry <ean Concrete (-<C) as sub,base layerunder constructionFi)" sho s pa$ement =uality concrete (5=C) layer under construction

Fi)"01 * $ie of si+ lane di$ided Bombay,5une #+press ay



Fi)" : Co48a'tio% o9 CNS Soi& (4oo ,4+ i% S,7) a$eCo%st ,'tio% 9o Ne* ;La%e Ca ia)e*a! (NH;?+



Fi)" : D ! Lea% Co%' ete (DLC+o% NH;? (Ko&#a8, ;Sata a Se'tio%+



Fi)" : Pa-e4e%t Q,a&it! Co%' ete (PQC+

o% NH;? (Ka)a&;Sata a Se'tio%+



Met#o$o&o)! o9 E47a%54e%t Co%st ,'tio%Case / I (i% C,tti%)+ (NH;?+

here the stretches of high ay embankment are incutting on BC 1oil (Fi)" 00+ and are belo 8;</



Fi)" 00: Hi)#*a! E47a%54e%t o% BC Soi&

i% C,tti%) 7e&o* NGL (NH;?+

Case – I (In Cutting)



Case / II (i% Fi&&i%)+

here the stretches of high ay embankment are infilling on BC soil (Fi)" 0 + and are abo$e 8;</



Fi)" 0 : Hi)#*a! E47a%54e%t

o% BC Soi& i% Fi&&i%) 7e&o* NGL (NH;?+

Case – II (In Filling)

C %'& i %



Co%'&,sio%s

There is a strong need for ground impro$ement in theengineering characteristics of BC soil for roads and "igh ay

Construction:se of <ime 3 Cement 1oil stabilisation technology has agreat potential in BC soil areas

:se of C81 (moorum) layer as a barrier bet een subgradeand subbase layer has been in practice in $ie of its cost,effecti$eness

:se of 229 mm thick sand filter layer on soft soils as a barrierto stop intrusion of subgrade soil in the granular sub,base layer

(;1B) as a drainage layer

Contd..



T#a%5 !o,

SS Seehra Black Cotton Soil Areas Final

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