832019 12949

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832019 12949

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Hydraulic Structures Instrumentation Sectional Committee RVD 16

FOREWORD

This Indian Standard was adopted by the Bureau of Indian Standards on 29 March 1990 after the draftfinalized by the Hydraulic Structures Instrumentation Sectional Committee had been approved by theRiver valley Division Council

The soil mass is composed of solid soil particles and voids filled with water and air The constructedembankment will always contain a certain volume of air and water within the voids The air iscompressible while water is highly incompressible Hence when embankment settles due to compactionby rolling or due to self weight the void space contract This causes pressure in the pore fluidcomprising air and water Thus the intergranular pressure is reduced due to opposing pore pressureand therefore the shear strength depends upon intergranular pressure

Pore pressure is also caused due to the seepage of water through an embankment The initial energy

head of percolating water at entrance into the dam isgreater than the-energy heat at any point in theinterior The difference represents the loss of energy due to friction forces of percolation The potentialof the water decreases as it seeps through the dam Pore pressure due to percolation is determined bysubtracting the corresponding elevation from the flow potential at that point being considered Thuspressure at any point in a dam at any time is the function of compaction consolidation and seepageProcedures for testing the pore pressure cells both in the laboratory and in the field before installationare under formulation

For the purpose of deciding whether a particular requirement of this standard is complied with thefinal value observed or calculated expressing the result of a test or analysis shall be rounded off inaccordance with IS 2 1960 lsquoRules for rounding off numerical values ( revised)lsquo The number ofsignificant places retained in the rounded off value should be the same as that of the specified value

in this standard

832019 12949

httpslidepdfcomreaderfull12949 311

IS 12949 1990

Indian Standard

CODE OF PRACTICE FOR INSTALLATION

MAINTENANCE AND OBSERVATION OF3NSTRUMENTS FOR PORE PRESSURE

MEASUREMENTS IN EARTH DAMS AND

ROCKFILL DAMS - ELECTRICAL PORE

PRESSURE CELLS VIBRATORY WIRE TYPE

1 SCOPE

11 This standard covers the details of installationobservation and maintenance of electrical porepressure cells ( vibrating wire type gt installed inearth and rockfill dams for measuring the porepressures in the embankment land the foundation

2 REFERENCES

21 The following Indian Standard is a necessaryadjunct to this standard

IS No Title

10034 1982 Code of practice for selectionsplicing installation andproviding protection to theopen ends of cables used forconnecting resistance typemeasuring devices in concreteand masonry dams

3 INSTALLATION EQUIPMENT

31 Electrical Pore Pressure Cells

The electrical pore pressure cell has a stainlesssteel diaphragm behind a porous filter element

The diaphragm is deflected by the pore waterpressure against one face the deflection beingproportional to the applied pressure Thedeflection of the diaphragm is measured bymeans of various electrical transducers mostcommon among them being unbounded resistancestrain gauge and vibrating wire strain gaugeElectrical piezometers have very small time lagsand are very sensitive Hence these are especiallysuited in the circumstances when the fluctuationsin pore pressures are very quick or in case ofdynamic observations

311 Vibrat ion W ire Type Pore Pressure Cells

The basic principle of the vibrating-wire straingauge is that the change in natural frequency ofvibration of a stretched wire depends qn the

change of the tension in the wire In practice agauge-wire is stretched between two points on astructural member or transducer element used tosense the physical quantities that are to bedetermined

3111 When the gauge-wire is caused tooscillate it will vibrate at its resonate or naturalfrequency of vibration which is dependent on thetension in the wire If strains are induced in theelement on which the gauge is mounted thedistance between the support posts -will changeAccordingly the tension in the gauge-wire and itsnatural frequency of vibration wihalso be changed

Thus the change in frequency of the gauge wireis a measure of the strain in the sensing elementof the transducer

3112 The main components of such an instru-ment are porous filter element diaphragmvibrating wire electro-magnet and connectingcable The pretensioned vibrating wire is suchconnected to the body of the cell and the~diaphragm that the tension of the wirechanges due to the deflection of the diaphragmonly Due to pore water pressure the diaphragm

is deflected and the natural frequency ofthe measuring wire is altered The mechanicaloscillation of the wire is converted toelectrical frequency signal by an electro-magnetand this electrical frequency is transmittedthrough the cable to the receiver unit andcorrelated to the pore pressure The frequency ofthe wire is independent of variations in voltagescurrents and resistance There are several typesof electrical piezometers and the main differencelies in the transducer package the porous elementand the arrangement of the body of the

piezometer

3113 The pore pressure cell should be structur-ally isolated from the surrounding concreteearthso that no apparent pore pressure are indicateddue to straining of the body of the instrument

I

832019 12949

httpslidepdfcomreaderfull12949 211

Hydraulic Structures Instrumentation Sectional Committee RVD 16

FOREWORD

This Indian Standard was adopted by the Bureau of Indian Standards on 29 March 1990 after the draftfinalized by the Hydraulic Structures Instrumentation Sectional Committee had been approved by theRiver valley Division Council

The soil mass is composed of solid soil particles and voids filled with water and air The constructedembankment will always contain a certain volume of air and water within the voids The air iscompressible while water is highly incompressible Hence when embankment settles due to compactionby rolling or due to self weight the void space contract This causes pressure in the pore fluidcomprising air and water Thus the intergranular pressure is reduced due to opposing pore pressureand therefore the shear strength depends upon intergranular pressure

Pore pressure is also caused due to the seepage of water through an embankment The initial energy

head of percolating water at entrance into the dam isgreater than the-energy heat at any point in theinterior The difference represents the loss of energy due to friction forces of percolation The potentialof the water decreases as it seeps through the dam Pore pressure due to percolation is determined bysubtracting the corresponding elevation from the flow potential at that point being considered Thuspressure at any point in a dam at any time is the function of compaction consolidation and seepageProcedures for testing the pore pressure cells both in the laboratory and in the field before installationare under formulation

For the purpose of deciding whether a particular requirement of this standard is complied with thefinal value observed or calculated expressing the result of a test or analysis shall be rounded off inaccordance with IS 2 1960 lsquoRules for rounding off numerical values ( revised)lsquo The number ofsignificant places retained in the rounded off value should be the same as that of the specified value

in this standard

832019 12949

httpslidepdfcomreaderfull12949 311

IS 12949 1990

Indian Standard

CODE OF PRACTICE FOR INSTALLATION

MAINTENANCE AND OBSERVATION OF3NSTRUMENTS FOR PORE PRESSURE

MEASUREMENTS IN EARTH DAMS AND

ROCKFILL DAMS - ELECTRICAL PORE

PRESSURE CELLS VIBRATORY WIRE TYPE

1 SCOPE

11 This standard covers the details of installationobservation and maintenance of electrical porepressure cells ( vibrating wire type gt installed inearth and rockfill dams for measuring the porepressures in the embankment land the foundation

2 REFERENCES

21 The following Indian Standard is a necessaryadjunct to this standard

IS No Title

10034 1982 Code of practice for selectionsplicing installation andproviding protection to theopen ends of cables used forconnecting resistance typemeasuring devices in concreteand masonry dams

3 INSTALLATION EQUIPMENT

31 Electrical Pore Pressure Cells

The electrical pore pressure cell has a stainlesssteel diaphragm behind a porous filter element

The diaphragm is deflected by the pore waterpressure against one face the deflection beingproportional to the applied pressure Thedeflection of the diaphragm is measured bymeans of various electrical transducers mostcommon among them being unbounded resistancestrain gauge and vibrating wire strain gaugeElectrical piezometers have very small time lagsand are very sensitive Hence these are especiallysuited in the circumstances when the fluctuationsin pore pressures are very quick or in case ofdynamic observations

311 Vibrat ion W ire Type Pore Pressure Cells

The basic principle of the vibrating-wire straingauge is that the change in natural frequency ofvibration of a stretched wire depends qn the

change of the tension in the wire In practice agauge-wire is stretched between two points on astructural member or transducer element used tosense the physical quantities that are to bedetermined

3111 When the gauge-wire is caused tooscillate it will vibrate at its resonate or naturalfrequency of vibration which is dependent on thetension in the wire If strains are induced in theelement on which the gauge is mounted thedistance between the support posts -will changeAccordingly the tension in the gauge-wire and itsnatural frequency of vibration wihalso be changed

Thus the change in frequency of the gauge wireis a measure of the strain in the sensing elementof the transducer

3112 The main components of such an instru-ment are porous filter element diaphragmvibrating wire electro-magnet and connectingcable The pretensioned vibrating wire is suchconnected to the body of the cell and the~diaphragm that the tension of the wirechanges due to the deflection of the diaphragmonly Due to pore water pressure the diaphragm

is deflected and the natural frequency ofthe measuring wire is altered The mechanicaloscillation of the wire is converted toelectrical frequency signal by an electro-magnetand this electrical frequency is transmittedthrough the cable to the receiver unit andcorrelated to the pore pressure The frequency ofthe wire is independent of variations in voltagescurrents and resistance There are several typesof electrical piezometers and the main differencelies in the transducer package the porous elementand the arrangement of the body of the

piezometer

3113 The pore pressure cell should be structur-ally isolated from the surrounding concreteearthso that no apparent pore pressure are indicateddue to straining of the body of the instrument

I

832019 12949

httpslidepdfcomreaderfull12949 311

IS 12949 1990

Indian Standard

CODE OF PRACTICE FOR INSTALLATION

MAINTENANCE AND OBSERVATION OF3NSTRUMENTS FOR PORE PRESSURE

MEASUREMENTS IN EARTH DAMS AND

ROCKFILL DAMS - ELECTRICAL PORE

PRESSURE CELLS VIBRATORY WIRE TYPE

1 SCOPE

11 This standard covers the details of installationobservation and maintenance of electrical porepressure cells ( vibrating wire type gt installed inearth and rockfill dams for measuring the porepressures in the embankment land the foundation

2 REFERENCES

21 The following Indian Standard is a necessaryadjunct to this standard

IS No Title

10034 1982 Code of practice for selectionsplicing installation andproviding protection to theopen ends of cables used forconnecting resistance typemeasuring devices in concreteand masonry dams

3 INSTALLATION EQUIPMENT

31 Electrical Pore Pressure Cells

The electrical pore pressure cell has a stainlesssteel diaphragm behind a porous filter element

The diaphragm is deflected by the pore waterpressure against one face the deflection beingproportional to the applied pressure Thedeflection of the diaphragm is measured bymeans of various electrical transducers mostcommon among them being unbounded resistancestrain gauge and vibrating wire strain gaugeElectrical piezometers have very small time lagsand are very sensitive Hence these are especiallysuited in the circumstances when the fluctuationsin pore pressures are very quick or in case ofdynamic observations

311 Vibrat ion W ire Type Pore Pressure Cells

The basic principle of the vibrating-wire straingauge is that the change in natural frequency ofvibration of a stretched wire depends qn the

change of the tension in the wire In practice agauge-wire is stretched between two points on astructural member or transducer element used tosense the physical quantities that are to bedetermined

3111 When the gauge-wire is caused tooscillate it will vibrate at its resonate or naturalfrequency of vibration which is dependent on thetension in the wire If strains are induced in theelement on which the gauge is mounted thedistance between the support posts -will changeAccordingly the tension in the gauge-wire and itsnatural frequency of vibration wihalso be changed

Thus the change in frequency of the gauge wireis a measure of the strain in the sensing elementof the transducer

3112 The main components of such an instru-ment are porous filter element diaphragmvibrating wire electro-magnet and connectingcable The pretensioned vibrating wire is suchconnected to the body of the cell and the~diaphragm that the tension of the wirechanges due to the deflection of the diaphragmonly Due to pore water pressure the diaphragm

is deflected and the natural frequency ofthe measuring wire is altered The mechanicaloscillation of the wire is converted toelectrical frequency signal by an electro-magnetand this electrical frequency is transmittedthrough the cable to the receiver unit andcorrelated to the pore pressure The frequency ofthe wire is independent of variations in voltagescurrents and resistance There are several typesof electrical piezometers and the main differencelies in the transducer package the porous elementand the arrangement of the body of the

piezometer

3113 The pore pressure cell should be structur-ally isolated from the surrounding concreteearthso that no apparent pore pressure are indicateddue to straining of the body of the instrument

I

832019 12949

httpslidepdfcomreaderfull12949 411

Is 12919 1990

32 Cable

The electrical type pore pressure cells shall besupplied with conductors of required length( see 321 ) attached to the instrument as agreedby the supplier and the purchaser The cable type

depends on the different makes of the instrumentsand for the details and specifications thecatalogue of the manufacturer may be referred toIn most installations the cable is recommended tobe further protected

When used in adverse environments cablesarmoured with steel wires having two layers ofinsulation with petroleum jelly filling to preventwater seepage may be used It is also recom-mended that the use of a junction box to connectseveral individual cables terminating in thejunction box and a steel armoured jelly filled

multi-core cable of 102040 conductors capabilitymay be used to connect these to a terminationswitch box installed in the terminal house

321 Cable Connections

The connection between the pore pressure cell andthe cable of required length to connect to thereadout unit is generally done in the factoryitself and in exceptional cases when the cable istoo short or has been damaged the cable connec-tions are done at site In such a case care shouldbe taken to get pressure-tight connections using

sealing compound The splicing shall be donein accordance with IS 10334 1982

322 Insulation Tests

After completion of the cable connections test thepore pressure cell for insulation by means of anohmmeter the value shall not be less than 500megaohms at 12 V There must -be no electricalconnection between each of the conductorsand the metal braiding or the body of thepore pressure cell After this the pore pressurecell shall be checked for proper functioning

These tests should be performed immediatelyafter the sealing resin has been applied

323 Identjfication of Cable Ends

After connecting the cable to the pore pressurecell the free end of the cable should be marked oridentified with permanent marks by use of aminimum of 3 tags at a maximum spacing of10 m over the entire exposed length of cable withnon-corrosive metal tags engraved or embossedwith appropriate transducer numbers Permanentidentification is necessary to prevent errors inidentifying the pore pressure cells

324 Cable Termination Arrangement

The number of cable joints should be minimisedusing continuous lengths wherever possible The

cable shall be of sufficient length to reach thepermanent readout station In case of necessityof joining the cables proper splicing kit shall beused The cables should be looped where theycross an interface and at joints to reduce thestrain in cables and joints due to differential

movement When there are sufficient porepressure cells to be installed which can justify useof an instrument house the cables have to belead through an entry duct connected to a suitableterminal unit If many pore pressure cells aregrouped together closely and the terminal unitis relatively far then suitable junction boxes shallbe used for connecting individual cables from thetransducers to a multicore cables which in turnconnected to the terminal unit

33 Installation of Pore Pressure Cells in the

Drill Holes

331 Pore pressure cells are installed in boreholes drilled below the foundations or throughalready completed embankments The minimumdiameter of bore holes shall be 100 mm for celldiameter up to 35 mm and 150 mm for celldiameter above 35 mm and up to 45 mm separatebore holes shall be drilled for each cell Casing ofthese wholes is usually required to maintain theholes during installation depending on localconditions and the type of equipment availableThe casing should be removed after the pore

pressure cell is placed in position3311 Procedure for installation of pore pressurecells in drill holes

a) Remove the high air entry filter from thecell and boil it in clear water for fiveminutes to saturate the filter with water

b) Reassemble the pore pressure cell undercool water by assembling the same in abucket of clean water The bucket shouldbe large enough to allow pore pressure cellto be reassembled and the placement of

the cell inside the cloth bag in submergedcondition

c) Place a cloth bag in the bucket of watermentioned above-and place some clean sandin the bag place the pore pressure cell in thebag and pack the sand above it as shownto get the assembly as indicated in Fig 1

d)

4

f 1

3

Tie the top of the bag by a suitable stringand place the same into the bronze metalscreen keeping the assembly submerged inwater

Take zero reading at this time to checkproper functioning of the cell

Clean the drill hole and fill up the bottom300 mm of hole with clean saturated sand

832019 12949

httpslidepdfcomreaderfull12949 511

If the hole has been provided with thecasing fill up the sand up to requireddepth and remove the casing from thebottom 300 mm prior to backfill operation

g) Lower the cell assembly into the hole up tothe top of the sand Test the pore pressurecell whether it is working satisfactorily

if yes continue with the steps below

h) Pour additional clean saturated sand tofill the hole up to 300 mm above the top ofthe cloth bag

i) Follow the backfilling as shown in Fig 2

332 Installation of Pore Pressure Cell in

Embankment

Pore pressure cells are placed in embankment inshallow trenches laid at right angles to the main

TIE STRING

I-zqAll dimensions in millimetres

IS 12949 990

trenches which carry the connecting cable from allthe cells The main trenches are offset 300 to600 mm from the location of cells Main trenchesare usually 450 to 600 mm wide and the depthshould provide for a minimum Of 100 mm ofselected material over the connecting cables and a300 mm thick protective cushion of selected fine

material in the bottom of the trenches below theconnecting cables A minimum of 450 mm ofembankment material should then be placed tocomplete the backfill to existing embankmentlevel

3321 Procedure for installation of pore pressurecells in embankment

a) Remove the high air entry filter from thecell and boil it in water for five minutes tosaturate the filter with water

PIEZOMETER CABLE

IfjBRONZE KETAL SCREEN

r---

_

-I

w [ TIE WIRE____ -

YCLkAN

8 ATuRA~_

-SMlD _B-0 l

Y

a __ -_

FIG 1 PORE PRESSURE CELL ASSEMBLY FORINSTALLATION IN ~)RXLL~OLES

3

832019 12949

httpslidepdfcomreaderfull12949 611

IS129491990

PXEZCMETER CALES 12 mm APMIT

HOLE FORFOUNDATION TYP E TIP

OFFSET TRENCH

b)

cl

d)

-_--OFFSET TRENCH

BENTONITE PLUG OF

SITE GONDITION DEMAND)

RE PRESSURE CELL ASSEMBLY

H

EAN SATURATED SAND

All dimensions in millimetres

F IG 2 TYP ICAL NSTALLATIONF P O R E P RESSURE ELL IN DRILL HOLES

Reassemble the pore pressure cell in abucket of cool water under submergedconditions

egt

Take zero reading at this time to check

proper functioning of the cell

f gt

g)Carry the cell to its desired location insubmerged condition

Place ICI0 mm thick layer of selected finematerial of the same type as that of thesurrounding embankment and compact

Place the pore pressure cell at its designedlocation as shown in Fig 3

Place selected fine embankment materialup to a thickness of 300 mm over the porepressure cell taking care so as to avoid

4

832019 12949

httpslidepdfcomreaderfull12949 711

large sized ~particles which can damage thepore pressure cell or the cable

h) Test the pore pressure cell for satisfactoryoperation

j) Backfill the lsquorest of the trench with typicalfill material and compact the same bymanual tamping

333 Laying of Cables

The cable shall be laid in main trenches wherebed is cleared of sharp edge objects and replacedwith selected material in slight wave lines Thetrench shall then be filled with selected finematerial up to a depth of 300 mm and handcompacted The main cable trenches should beprovided with a cross cut-off trench filled with1 3 soil bentonite mixture to prevent formationof a possible seepage path in the body of theearthrockfill dam Heavy machinery shall notbe allowed to pass within 2 000 mm of theinstrument and before 2 000 mm covering heightover the instrument

At locations where the cable passes in transitionzones of the embankment differential settlementof fill materials may shear the cable adequateprovision shall be made by providing extra looselength of cable in that portion

While routing of cables through rockfill themain trenches carrying cables shall be filled with

IS 12949 1990

coarse to fine sand completely passing 5 mm seiveThe relative spacing between individual layersof cables as shown in Fig 4 may be maintainedThe graded material surrounding the main trenchshall be provided with properly graded layers toprevent migration of sand filling in the maintrench

The cables shall be protected against prolongedexposure to sun and mechanical damage It istherefore necessary that the cable is properlycovered at all times

334 Cable Ends

The free ends of the installed cable shall beterminated immediately in water-tight connectionsEntry of moisture through open ends of cablecan ultimately result in making the pore pressurecell inoperative

335 Precautions Against At mos pheric O ver-

Voltages

Suitable over-voltage protection shall be providedto safeguard the transducer and the terminalunit from atmospheric over-voltages

4 OBSERVATIONS

41 Initial Reading

411 After the installation of each piezometer

VARIFS

I

~11 dimensions in millimetres

Bentonite plug ( lsquo4 mixture of 5 Bentonite ( by Volume ) and 950 Embankment Material Shoudbe placed lsquo15rsquo Metre Intervals or Midway Between the Plezometer TIPS Whenever Distance IS

Smaller )

FIG 3 TYPICAL INSTALLATION OF PORE PRESSURE CELL IN EMBANKMENT ( Contd )

5

832019 12949

httpslidepdfcomreaderfull12949 811

IS 12949 1990

SE

MANUALlYRACK

LECTEO FINE

MATERILL

COMPACTED

FILLLEVEL

FINE MATERIAL

A-A

EMBANKMENT

SOIL

c C-- crsquoNE

SOIL

RlAamp

All dimensions in mihpetres

FIG 3 TYPICALINSTALLATION OF PORE PRESSURE CELL INE MBANKMENT

sta bilizing near th e piezomcter tip will take sometime depending on soil permeability pore

pressure gradient etc A judgement in each case isnecessary to decide when piezometer readings cantake place Normally the pore pressure will bestable within 48 hours of installation A readingat this stage shall be taken and shall be recordedas the initial reading

412 The pore pressure cell is temperaturecompensated that is temperature fluctuations ofthe surrounding soil will not affect the measuringresult provide_d the entire cell is in a state oftemperature balance ( the measuring -wire should

be at the same temperat ure as the body of th e

cell)

42 Recording of Observation

Different systems of recording observations ofvibrating wire type instruments are available Forrecording observations instruments of the manu-facturers of the respective makes should be referredto

43 Frequency of Observation

Pore pressure readings shall be taken at every15 days interval during construction and atmonthly intervals during shut down After

6

832019 12949

httpslidepdfcomreaderfull12949 911

IS129491990

ROCK

All dimensions in millimetres

FIG 4 LAYING CABLES THROUGH ROCKFILL

construction during initial reservoir filling thereadings shall be taken for every 3 m rise or fall

be duly processed and the following graphsprepared

of the reservoir or at monthly intervals Aftertwo years the readings should be taken at every3-monthly intervals except during rainy seasonwhen readings should be taken at monthlyintervals

5 PRESENTATION OF DATA

51 The data from piezometric observations shall

Pore pressure reservoir level and embank-ment height versus time

Pore pressure versus total stress and

The distribution of the above parameteralong with geometry of the place with thecontours and cross sections

832019 12949

httpslidepdfcomreaderfull12949 1011

Standard Mark

The useStandards Act

of the Standard Mark is governed by the provisions of the Bureau of Indian1986 and the Rules and Regulations made thereunder The Standard Mark on

products covered by an Indian Standard conveys the assurance that they have been producedto comply with the requirements of that standard under a well defined system of inspectiontesting and quality control which is devised and supervised by BIS and operated by theproducer Standard marked products are also continuously checked by BIS for conformityto that standard as a further safeguard Details of conditions under which a licence for theuse of the Standard Mark may be granted to manufacturers or producers may be obtainedfrom the Bureau of Indian Standards

832019 12949

httpslidepdfcomreaderfull12949 1111

BiS ia a statutory institution amptamplamphamp under the -ampauamp o f I r d i k q S p e s l d a r i l sc t 986 to promoteharmonious development oftamp campampiampf standardizatioti marking and quality certification of goodsand atampding to connected mstbsrs in ttlre country

_

wdlP

z I

II lsquo1_ rsquo

BIS haq the copyright -dfrsquo amplsquoitamppublittio6 lsquoI$ii amprC of these publications may he reproduced inaxtyrsquoform without the prior -iampion inwriting of BIS This doamp not preclude the free use in thecoampse of implementing the ~standard of nesary details such as symbols and sizes type or gradedesignations Enquiries relating to copyrigtit be addressed to tbe Director ( Publications ) BIS

Revlsioa of Indian Stamdmls

Indian Standards are reviewed periodically and revised when necessary and amendments if any areissued from time to time Users of Indian Standards should ascertain that they are in possession ofthe latest amendments or edition Comments on this Indian Standard may be sent to BIS giving thefollowing reference

Dot No RVD 16 ( 2953 )

Amendments Issued Since Publication

Amend No Date of Issue Text Affected

BUREAU OF INDIAN STANDARDS

Headquarters

Manak Bhavan 9 Bahadur Shah Zafar Marg New Delhi 110002$lsquoelephones 331 01 31 331 13 75

Regional Offices Telephone

Central Manak Bhavan 9 Bahadur Shah Zafar Marg 33101 31

NEW DELHI 110002 331 13 75

Eastern l14 C I T Scheme VII M V I P Road ManiktolaCALCUTTA 700054

37 86 62

Northern SC0 445-446 Sector 35-C CHANDIGARH 160036

Southern C I T Campus IV Cross Road MADRAS 600113

Western Manakalaya E9 MIDC Marol Andheri ( East )

BOMBAY 400093

2 18 43

41 29 16

6 32 92 95

Branches AHMADABAD BANGALORE BHOPAL BHUBANESHWAR COIMBATOREFARIDABAD GHAZIABAD GUWAHATI HYDERABAD JAIPUR KANPURPATNA THIRUVANANTHAPURAM

Printed at Printwell Printers Delhi India

832019 12949

httpslidepdfcomreaderfull12949 511

If the hole has been provided with thecasing fill up the sand up to requireddepth and remove the casing from thebottom 300 mm prior to backfill operation

g) Lower the cell assembly into the hole up tothe top of the sand Test the pore pressurecell whether it is working satisfactorily

if yes continue with the steps below

h) Pour additional clean saturated sand tofill the hole up to 300 mm above the top ofthe cloth bag

i) Follow the backfilling as shown in Fig 2

332 Installation of Pore Pressure Cell in

Embankment

Pore pressure cells are placed in embankment inshallow trenches laid at right angles to the main

TIE STRING

I-zqAll dimensions in millimetres

IS 12949 990

trenches which carry the connecting cable from allthe cells The main trenches are offset 300 to600 mm from the location of cells Main trenchesare usually 450 to 600 mm wide and the depthshould provide for a minimum Of 100 mm ofselected material over the connecting cables and a300 mm thick protective cushion of selected fine

material in the bottom of the trenches below theconnecting cables A minimum of 450 mm ofembankment material should then be placed tocomplete the backfill to existing embankmentlevel

3321 Procedure for installation of pore pressurecells in embankment

a) Remove the high air entry filter from thecell and boil it in water for five minutes tosaturate the filter with water

PIEZOMETER CABLE

IfjBRONZE KETAL SCREEN

r---

_

-I

w [ TIE WIRE____ -

YCLkAN

8 ATuRA~_

-SMlD _B-0 l

Y

a __ -_

FIG 1 PORE PRESSURE CELL ASSEMBLY FORINSTALLATION IN ~)RXLL~OLES

3

832019 12949

httpslidepdfcomreaderfull12949 611

IS129491990

PXEZCMETER CALES 12 mm APMIT

HOLE FORFOUNDATION TYP E TIP

OFFSET TRENCH

b)

cl

d)

-_--OFFSET TRENCH

BENTONITE PLUG OF

SITE GONDITION DEMAND)

RE PRESSURE CELL ASSEMBLY

H

EAN SATURATED SAND

All dimensions in millimetres

F IG 2 TYP ICAL NSTALLATIONF P O R E P RESSURE ELL IN DRILL HOLES

Reassemble the pore pressure cell in abucket of cool water under submergedconditions

egt

Take zero reading at this time to check

proper functioning of the cell

f gt

g)Carry the cell to its desired location insubmerged condition

Place ICI0 mm thick layer of selected finematerial of the same type as that of thesurrounding embankment and compact

Place the pore pressure cell at its designedlocation as shown in Fig 3

Place selected fine embankment materialup to a thickness of 300 mm over the porepressure cell taking care so as to avoid

4

832019 12949

httpslidepdfcomreaderfull12949 711

large sized ~particles which can damage thepore pressure cell or the cable

h) Test the pore pressure cell for satisfactoryoperation

j) Backfill the lsquorest of the trench with typicalfill material and compact the same bymanual tamping

333 Laying of Cables

The cable shall be laid in main trenches wherebed is cleared of sharp edge objects and replacedwith selected material in slight wave lines Thetrench shall then be filled with selected finematerial up to a depth of 300 mm and handcompacted The main cable trenches should beprovided with a cross cut-off trench filled with1 3 soil bentonite mixture to prevent formationof a possible seepage path in the body of theearthrockfill dam Heavy machinery shall notbe allowed to pass within 2 000 mm of theinstrument and before 2 000 mm covering heightover the instrument

At locations where the cable passes in transitionzones of the embankment differential settlementof fill materials may shear the cable adequateprovision shall be made by providing extra looselength of cable in that portion

While routing of cables through rockfill themain trenches carrying cables shall be filled with

IS 12949 1990

coarse to fine sand completely passing 5 mm seiveThe relative spacing between individual layersof cables as shown in Fig 4 may be maintainedThe graded material surrounding the main trenchshall be provided with properly graded layers toprevent migration of sand filling in the maintrench

The cables shall be protected against prolongedexposure to sun and mechanical damage It istherefore necessary that the cable is properlycovered at all times

334 Cable Ends

The free ends of the installed cable shall beterminated immediately in water-tight connectionsEntry of moisture through open ends of cablecan ultimately result in making the pore pressurecell inoperative

335 Precautions Against At mos pheric O ver-

Voltages

Suitable over-voltage protection shall be providedto safeguard the transducer and the terminalunit from atmospheric over-voltages

4 OBSERVATIONS

41 Initial Reading

411 After the installation of each piezometer

VARIFS

I

~11 dimensions in millimetres

Bentonite plug ( lsquo4 mixture of 5 Bentonite ( by Volume ) and 950 Embankment Material Shoudbe placed lsquo15rsquo Metre Intervals or Midway Between the Plezometer TIPS Whenever Distance IS

Smaller )

FIG 3 TYPICAL INSTALLATION OF PORE PRESSURE CELL IN EMBANKMENT ( Contd )

5

832019 12949

httpslidepdfcomreaderfull12949 811

IS 12949 1990

SE

MANUALlYRACK

LECTEO FINE

MATERILL

COMPACTED

FILLLEVEL

FINE MATERIAL

A-A

EMBANKMENT

SOIL

c C-- crsquoNE

SOIL

RlAamp

All dimensions in mihpetres

FIG 3 TYPICALINSTALLATION OF PORE PRESSURE CELL INE MBANKMENT

sta bilizing near th e piezomcter tip will take sometime depending on soil permeability pore

pressure gradient etc A judgement in each case isnecessary to decide when piezometer readings cantake place Normally the pore pressure will bestable within 48 hours of installation A readingat this stage shall be taken and shall be recordedas the initial reading

412 The pore pressure cell is temperaturecompensated that is temperature fluctuations ofthe surrounding soil will not affect the measuringresult provide_d the entire cell is in a state oftemperature balance ( the measuring -wire should

be at the same temperat ure as the body of th e

cell)

42 Recording of Observation

Different systems of recording observations ofvibrating wire type instruments are available Forrecording observations instruments of the manu-facturers of the respective makes should be referredto

43 Frequency of Observation

Pore pressure readings shall be taken at every15 days interval during construction and atmonthly intervals during shut down After

6

832019 12949

httpslidepdfcomreaderfull12949 911

IS129491990

ROCK

All dimensions in millimetres

FIG 4 LAYING CABLES THROUGH ROCKFILL

construction during initial reservoir filling thereadings shall be taken for every 3 m rise or fall

be duly processed and the following graphsprepared

of the reservoir or at monthly intervals Aftertwo years the readings should be taken at every3-monthly intervals except during rainy seasonwhen readings should be taken at monthlyintervals

5 PRESENTATION OF DATA

51 The data from piezometric observations shall

Pore pressure reservoir level and embank-ment height versus time

Pore pressure versus total stress and

The distribution of the above parameteralong with geometry of the place with thecontours and cross sections

832019 12949

httpslidepdfcomreaderfull12949 1011

Standard Mark

The useStandards Act

of the Standard Mark is governed by the provisions of the Bureau of Indian1986 and the Rules and Regulations made thereunder The Standard Mark on

products covered by an Indian Standard conveys the assurance that they have been producedto comply with the requirements of that standard under a well defined system of inspectiontesting and quality control which is devised and supervised by BIS and operated by theproducer Standard marked products are also continuously checked by BIS for conformityto that standard as a further safeguard Details of conditions under which a licence for theuse of the Standard Mark may be granted to manufacturers or producers may be obtainedfrom the Bureau of Indian Standards

832019 12949

httpslidepdfcomreaderfull12949 1111

BiS ia a statutory institution amptamplamphamp under the -ampauamp o f I r d i k q S p e s l d a r i l sc t 986 to promoteharmonious development oftamp campampiampf standardizatioti marking and quality certification of goodsand atampding to connected mstbsrs in ttlre country

_

wdlP

z I

II lsquo1_ rsquo

BIS haq the copyright -dfrsquo amplsquoitamppublittio6 lsquoI$ii amprC of these publications may he reproduced inaxtyrsquoform without the prior -iampion inwriting of BIS This doamp not preclude the free use in thecoampse of implementing the ~standard of nesary details such as symbols and sizes type or gradedesignations Enquiries relating to copyrigtit be addressed to tbe Director ( Publications ) BIS

Revlsioa of Indian Stamdmls

Indian Standards are reviewed periodically and revised when necessary and amendments if any areissued from time to time Users of Indian Standards should ascertain that they are in possession ofthe latest amendments or edition Comments on this Indian Standard may be sent to BIS giving thefollowing reference

Dot No RVD 16 ( 2953 )

Amendments Issued Since Publication

Amend No Date of Issue Text Affected

BUREAU OF INDIAN STANDARDS

Headquarters

Manak Bhavan 9 Bahadur Shah Zafar Marg New Delhi 110002$lsquoelephones 331 01 31 331 13 75

Regional Offices Telephone

Central Manak Bhavan 9 Bahadur Shah Zafar Marg 33101 31

NEW DELHI 110002 331 13 75

Eastern l14 C I T Scheme VII M V I P Road ManiktolaCALCUTTA 700054

37 86 62

Northern SC0 445-446 Sector 35-C CHANDIGARH 160036

Southern C I T Campus IV Cross Road MADRAS 600113

Western Manakalaya E9 MIDC Marol Andheri ( East )

BOMBAY 400093

2 18 43

41 29 16

6 32 92 95

Branches AHMADABAD BANGALORE BHOPAL BHUBANESHWAR COIMBATOREFARIDABAD GHAZIABAD GUWAHATI HYDERABAD JAIPUR KANPURPATNA THIRUVANANTHAPURAM

Printed at Printwell Printers Delhi India

832019 12949

httpslidepdfcomreaderfull12949 611

IS129491990

PXEZCMETER CALES 12 mm APMIT

HOLE FORFOUNDATION TYP E TIP

OFFSET TRENCH

b)

cl

d)

-_--OFFSET TRENCH

BENTONITE PLUG OF

SITE GONDITION DEMAND)

RE PRESSURE CELL ASSEMBLY

H

EAN SATURATED SAND

All dimensions in millimetres

F IG 2 TYP ICAL NSTALLATIONF P O R E P RESSURE ELL IN DRILL HOLES

Reassemble the pore pressure cell in abucket of cool water under submergedconditions

egt

Take zero reading at this time to check

proper functioning of the cell

f gt

g)Carry the cell to its desired location insubmerged condition

Place ICI0 mm thick layer of selected finematerial of the same type as that of thesurrounding embankment and compact

Place the pore pressure cell at its designedlocation as shown in Fig 3

Place selected fine embankment materialup to a thickness of 300 mm over the porepressure cell taking care so as to avoid

4

832019 12949

httpslidepdfcomreaderfull12949 711

large sized ~particles which can damage thepore pressure cell or the cable

h) Test the pore pressure cell for satisfactoryoperation

j) Backfill the lsquorest of the trench with typicalfill material and compact the same bymanual tamping

333 Laying of Cables

The cable shall be laid in main trenches wherebed is cleared of sharp edge objects and replacedwith selected material in slight wave lines Thetrench shall then be filled with selected finematerial up to a depth of 300 mm and handcompacted The main cable trenches should beprovided with a cross cut-off trench filled with1 3 soil bentonite mixture to prevent formationof a possible seepage path in the body of theearthrockfill dam Heavy machinery shall notbe allowed to pass within 2 000 mm of theinstrument and before 2 000 mm covering heightover the instrument

At locations where the cable passes in transitionzones of the embankment differential settlementof fill materials may shear the cable adequateprovision shall be made by providing extra looselength of cable in that portion

While routing of cables through rockfill themain trenches carrying cables shall be filled with

IS 12949 1990

coarse to fine sand completely passing 5 mm seiveThe relative spacing between individual layersof cables as shown in Fig 4 may be maintainedThe graded material surrounding the main trenchshall be provided with properly graded layers toprevent migration of sand filling in the maintrench

The cables shall be protected against prolongedexposure to sun and mechanical damage It istherefore necessary that the cable is properlycovered at all times

334 Cable Ends

The free ends of the installed cable shall beterminated immediately in water-tight connectionsEntry of moisture through open ends of cablecan ultimately result in making the pore pressurecell inoperative

335 Precautions Against At mos pheric O ver-

Voltages

Suitable over-voltage protection shall be providedto safeguard the transducer and the terminalunit from atmospheric over-voltages

4 OBSERVATIONS

41 Initial Reading

411 After the installation of each piezometer

VARIFS

I

~11 dimensions in millimetres

Bentonite plug ( lsquo4 mixture of 5 Bentonite ( by Volume ) and 950 Embankment Material Shoudbe placed lsquo15rsquo Metre Intervals or Midway Between the Plezometer TIPS Whenever Distance IS

Smaller )

FIG 3 TYPICAL INSTALLATION OF PORE PRESSURE CELL IN EMBANKMENT ( Contd )

5

832019 12949

httpslidepdfcomreaderfull12949 811

IS 12949 1990

SE

MANUALlYRACK

LECTEO FINE

MATERILL

COMPACTED

FILLLEVEL

FINE MATERIAL

A-A

EMBANKMENT

SOIL

c C-- crsquoNE

SOIL

RlAamp

All dimensions in mihpetres

FIG 3 TYPICALINSTALLATION OF PORE PRESSURE CELL INE MBANKMENT

sta bilizing near th e piezomcter tip will take sometime depending on soil permeability pore

pressure gradient etc A judgement in each case isnecessary to decide when piezometer readings cantake place Normally the pore pressure will bestable within 48 hours of installation A readingat this stage shall be taken and shall be recordedas the initial reading

412 The pore pressure cell is temperaturecompensated that is temperature fluctuations ofthe surrounding soil will not affect the measuringresult provide_d the entire cell is in a state oftemperature balance ( the measuring -wire should

be at the same temperat ure as the body of th e

cell)

42 Recording of Observation

Different systems of recording observations ofvibrating wire type instruments are available Forrecording observations instruments of the manu-facturers of the respective makes should be referredto

43 Frequency of Observation

Pore pressure readings shall be taken at every15 days interval during construction and atmonthly intervals during shut down After

6

832019 12949

httpslidepdfcomreaderfull12949 911

IS129491990

ROCK

All dimensions in millimetres

FIG 4 LAYING CABLES THROUGH ROCKFILL

construction during initial reservoir filling thereadings shall be taken for every 3 m rise or fall

be duly processed and the following graphsprepared

of the reservoir or at monthly intervals Aftertwo years the readings should be taken at every3-monthly intervals except during rainy seasonwhen readings should be taken at monthlyintervals

5 PRESENTATION OF DATA

51 The data from piezometric observations shall

Pore pressure reservoir level and embank-ment height versus time

Pore pressure versus total stress and

The distribution of the above parameteralong with geometry of the place with thecontours and cross sections

832019 12949

httpslidepdfcomreaderfull12949 1011

Standard Mark

The useStandards Act

of the Standard Mark is governed by the provisions of the Bureau of Indian1986 and the Rules and Regulations made thereunder The Standard Mark on

products covered by an Indian Standard conveys the assurance that they have been producedto comply with the requirements of that standard under a well defined system of inspectiontesting and quality control which is devised and supervised by BIS and operated by theproducer Standard marked products are also continuously checked by BIS for conformityto that standard as a further safeguard Details of conditions under which a licence for theuse of the Standard Mark may be granted to manufacturers or producers may be obtainedfrom the Bureau of Indian Standards

832019 12949

httpslidepdfcomreaderfull12949 1111

BiS ia a statutory institution amptamplamphamp under the -ampauamp o f I r d i k q S p e s l d a r i l sc t 986 to promoteharmonious development oftamp campampiampf standardizatioti marking and quality certification of goodsand atampding to connected mstbsrs in ttlre country

_

wdlP

z I

II lsquo1_ rsquo

BIS haq the copyright -dfrsquo amplsquoitamppublittio6 lsquoI$ii amprC of these publications may he reproduced inaxtyrsquoform without the prior -iampion inwriting of BIS This doamp not preclude the free use in thecoampse of implementing the ~standard of nesary details such as symbols and sizes type or gradedesignations Enquiries relating to copyrigtit be addressed to tbe Director ( Publications ) BIS

Revlsioa of Indian Stamdmls

Indian Standards are reviewed periodically and revised when necessary and amendments if any areissued from time to time Users of Indian Standards should ascertain that they are in possession ofthe latest amendments or edition Comments on this Indian Standard may be sent to BIS giving thefollowing reference

Dot No RVD 16 ( 2953 )

Amendments Issued Since Publication

Amend No Date of Issue Text Affected

BUREAU OF INDIAN STANDARDS

Headquarters

Manak Bhavan 9 Bahadur Shah Zafar Marg New Delhi 110002$lsquoelephones 331 01 31 331 13 75

Regional Offices Telephone

Central Manak Bhavan 9 Bahadur Shah Zafar Marg 33101 31

NEW DELHI 110002 331 13 75

Eastern l14 C I T Scheme VII M V I P Road ManiktolaCALCUTTA 700054

37 86 62

Northern SC0 445-446 Sector 35-C CHANDIGARH 160036

Southern C I T Campus IV Cross Road MADRAS 600113

Western Manakalaya E9 MIDC Marol Andheri ( East )

BOMBAY 400093

2 18 43

41 29 16

6 32 92 95

Branches AHMADABAD BANGALORE BHOPAL BHUBANESHWAR COIMBATOREFARIDABAD GHAZIABAD GUWAHATI HYDERABAD JAIPUR KANPURPATNA THIRUVANANTHAPURAM

Printed at Printwell Printers Delhi India

832019 12949

httpslidepdfcomreaderfull12949 711

large sized ~particles which can damage thepore pressure cell or the cable

h) Test the pore pressure cell for satisfactoryoperation

j) Backfill the lsquorest of the trench with typicalfill material and compact the same bymanual tamping

333 Laying of Cables

The cable shall be laid in main trenches wherebed is cleared of sharp edge objects and replacedwith selected material in slight wave lines Thetrench shall then be filled with selected finematerial up to a depth of 300 mm and handcompacted The main cable trenches should beprovided with a cross cut-off trench filled with1 3 soil bentonite mixture to prevent formationof a possible seepage path in the body of theearthrockfill dam Heavy machinery shall notbe allowed to pass within 2 000 mm of theinstrument and before 2 000 mm covering heightover the instrument

At locations where the cable passes in transitionzones of the embankment differential settlementof fill materials may shear the cable adequateprovision shall be made by providing extra looselength of cable in that portion

While routing of cables through rockfill themain trenches carrying cables shall be filled with

IS 12949 1990

coarse to fine sand completely passing 5 mm seiveThe relative spacing between individual layersof cables as shown in Fig 4 may be maintainedThe graded material surrounding the main trenchshall be provided with properly graded layers toprevent migration of sand filling in the maintrench

The cables shall be protected against prolongedexposure to sun and mechanical damage It istherefore necessary that the cable is properlycovered at all times

334 Cable Ends

The free ends of the installed cable shall beterminated immediately in water-tight connectionsEntry of moisture through open ends of cablecan ultimately result in making the pore pressurecell inoperative

335 Precautions Against At mos pheric O ver-

Voltages

Suitable over-voltage protection shall be providedto safeguard the transducer and the terminalunit from atmospheric over-voltages

4 OBSERVATIONS

41 Initial Reading

411 After the installation of each piezometer

VARIFS

I

~11 dimensions in millimetres

Bentonite plug ( lsquo4 mixture of 5 Bentonite ( by Volume ) and 950 Embankment Material Shoudbe placed lsquo15rsquo Metre Intervals or Midway Between the Plezometer TIPS Whenever Distance IS

Smaller )

FIG 3 TYPICAL INSTALLATION OF PORE PRESSURE CELL IN EMBANKMENT ( Contd )

5

832019 12949

httpslidepdfcomreaderfull12949 811

IS 12949 1990

SE

MANUALlYRACK

LECTEO FINE

MATERILL

COMPACTED

FILLLEVEL

FINE MATERIAL

A-A

EMBANKMENT

SOIL

c C-- crsquoNE

SOIL

RlAamp

All dimensions in mihpetres

FIG 3 TYPICALINSTALLATION OF PORE PRESSURE CELL INE MBANKMENT

sta bilizing near th e piezomcter tip will take sometime depending on soil permeability pore

pressure gradient etc A judgement in each case isnecessary to decide when piezometer readings cantake place Normally the pore pressure will bestable within 48 hours of installation A readingat this stage shall be taken and shall be recordedas the initial reading

412 The pore pressure cell is temperaturecompensated that is temperature fluctuations ofthe surrounding soil will not affect the measuringresult provide_d the entire cell is in a state oftemperature balance ( the measuring -wire should

be at the same temperat ure as the body of th e

cell)

42 Recording of Observation

Different systems of recording observations ofvibrating wire type instruments are available Forrecording observations instruments of the manu-facturers of the respective makes should be referredto

43 Frequency of Observation

Pore pressure readings shall be taken at every15 days interval during construction and atmonthly intervals during shut down After

6

832019 12949

httpslidepdfcomreaderfull12949 911

IS129491990

ROCK

All dimensions in millimetres

FIG 4 LAYING CABLES THROUGH ROCKFILL

construction during initial reservoir filling thereadings shall be taken for every 3 m rise or fall

be duly processed and the following graphsprepared

of the reservoir or at monthly intervals Aftertwo years the readings should be taken at every3-monthly intervals except during rainy seasonwhen readings should be taken at monthlyintervals

5 PRESENTATION OF DATA

51 The data from piezometric observations shall

Pore pressure reservoir level and embank-ment height versus time

Pore pressure versus total stress and

The distribution of the above parameteralong with geometry of the place with thecontours and cross sections

832019 12949

httpslidepdfcomreaderfull12949 1011

Standard Mark

The useStandards Act

of the Standard Mark is governed by the provisions of the Bureau of Indian1986 and the Rules and Regulations made thereunder The Standard Mark on

products covered by an Indian Standard conveys the assurance that they have been producedto comply with the requirements of that standard under a well defined system of inspectiontesting and quality control which is devised and supervised by BIS and operated by theproducer Standard marked products are also continuously checked by BIS for conformityto that standard as a further safeguard Details of conditions under which a licence for theuse of the Standard Mark may be granted to manufacturers or producers may be obtainedfrom the Bureau of Indian Standards

832019 12949

httpslidepdfcomreaderfull12949 1111

BiS ia a statutory institution amptamplamphamp under the -ampauamp o f I r d i k q S p e s l d a r i l sc t 986 to promoteharmonious development oftamp campampiampf standardizatioti marking and quality certification of goodsand atampding to connected mstbsrs in ttlre country

_

wdlP

z I

II lsquo1_ rsquo

BIS haq the copyright -dfrsquo amplsquoitamppublittio6 lsquoI$ii amprC of these publications may he reproduced inaxtyrsquoform without the prior -iampion inwriting of BIS This doamp not preclude the free use in thecoampse of implementing the ~standard of nesary details such as symbols and sizes type or gradedesignations Enquiries relating to copyrigtit be addressed to tbe Director ( Publications ) BIS

Revlsioa of Indian Stamdmls

Indian Standards are reviewed periodically and revised when necessary and amendments if any areissued from time to time Users of Indian Standards should ascertain that they are in possession ofthe latest amendments or edition Comments on this Indian Standard may be sent to BIS giving thefollowing reference

Dot No RVD 16 ( 2953 )

Amendments Issued Since Publication

Amend No Date of Issue Text Affected

BUREAU OF INDIAN STANDARDS

Headquarters

Manak Bhavan 9 Bahadur Shah Zafar Marg New Delhi 110002$lsquoelephones 331 01 31 331 13 75

Regional Offices Telephone

Central Manak Bhavan 9 Bahadur Shah Zafar Marg 33101 31

NEW DELHI 110002 331 13 75

Eastern l14 C I T Scheme VII M V I P Road ManiktolaCALCUTTA 700054

37 86 62

Northern SC0 445-446 Sector 35-C CHANDIGARH 160036

Southern C I T Campus IV Cross Road MADRAS 600113

Western Manakalaya E9 MIDC Marol Andheri ( East )

BOMBAY 400093

2 18 43

41 29 16

6 32 92 95

Branches AHMADABAD BANGALORE BHOPAL BHUBANESHWAR COIMBATOREFARIDABAD GHAZIABAD GUWAHATI HYDERABAD JAIPUR KANPURPATNA THIRUVANANTHAPURAM

Printed at Printwell Printers Delhi India

832019 12949

httpslidepdfcomreaderfull12949 811

IS 12949 1990

SE

MANUALlYRACK

LECTEO FINE

MATERILL

COMPACTED

FILLLEVEL

FINE MATERIAL

A-A

EMBANKMENT

SOIL

c C-- crsquoNE

SOIL

RlAamp

All dimensions in mihpetres

FIG 3 TYPICALINSTALLATION OF PORE PRESSURE CELL INE MBANKMENT

sta bilizing near th e piezomcter tip will take sometime depending on soil permeability pore

pressure gradient etc A judgement in each case isnecessary to decide when piezometer readings cantake place Normally the pore pressure will bestable within 48 hours of installation A readingat this stage shall be taken and shall be recordedas the initial reading

412 The pore pressure cell is temperaturecompensated that is temperature fluctuations ofthe surrounding soil will not affect the measuringresult provide_d the entire cell is in a state oftemperature balance ( the measuring -wire should

be at the same temperat ure as the body of th e

cell)

42 Recording of Observation

Different systems of recording observations ofvibrating wire type instruments are available Forrecording observations instruments of the manu-facturers of the respective makes should be referredto

43 Frequency of Observation

Pore pressure readings shall be taken at every15 days interval during construction and atmonthly intervals during shut down After

6

832019 12949

httpslidepdfcomreaderfull12949 911

IS129491990

ROCK

All dimensions in millimetres

FIG 4 LAYING CABLES THROUGH ROCKFILL

construction during initial reservoir filling thereadings shall be taken for every 3 m rise or fall

be duly processed and the following graphsprepared

of the reservoir or at monthly intervals Aftertwo years the readings should be taken at every3-monthly intervals except during rainy seasonwhen readings should be taken at monthlyintervals

5 PRESENTATION OF DATA

51 The data from piezometric observations shall

Pore pressure reservoir level and embank-ment height versus time

Pore pressure versus total stress and

The distribution of the above parameteralong with geometry of the place with thecontours and cross sections

832019 12949

httpslidepdfcomreaderfull12949 1011

Standard Mark

The useStandards Act

of the Standard Mark is governed by the provisions of the Bureau of Indian1986 and the Rules and Regulations made thereunder The Standard Mark on

products covered by an Indian Standard conveys the assurance that they have been producedto comply with the requirements of that standard under a well defined system of inspectiontesting and quality control which is devised and supervised by BIS and operated by theproducer Standard marked products are also continuously checked by BIS for conformityto that standard as a further safeguard Details of conditions under which a licence for theuse of the Standard Mark may be granted to manufacturers or producers may be obtainedfrom the Bureau of Indian Standards

832019 12949

httpslidepdfcomreaderfull12949 1111

BiS ia a statutory institution amptamplamphamp under the -ampauamp o f I r d i k q S p e s l d a r i l sc t 986 to promoteharmonious development oftamp campampiampf standardizatioti marking and quality certification of goodsand atampding to connected mstbsrs in ttlre country

_

wdlP

z I

II lsquo1_ rsquo

BIS haq the copyright -dfrsquo amplsquoitamppublittio6 lsquoI$ii amprC of these publications may he reproduced inaxtyrsquoform without the prior -iampion inwriting of BIS This doamp not preclude the free use in thecoampse of implementing the ~standard of nesary details such as symbols and sizes type or gradedesignations Enquiries relating to copyrigtit be addressed to tbe Director ( Publications ) BIS

Revlsioa of Indian Stamdmls

Indian Standards are reviewed periodically and revised when necessary and amendments if any areissued from time to time Users of Indian Standards should ascertain that they are in possession ofthe latest amendments or edition Comments on this Indian Standard may be sent to BIS giving thefollowing reference

Dot No RVD 16 ( 2953 )

Amendments Issued Since Publication

Amend No Date of Issue Text Affected

BUREAU OF INDIAN STANDARDS

Headquarters

Manak Bhavan 9 Bahadur Shah Zafar Marg New Delhi 110002$lsquoelephones 331 01 31 331 13 75

Regional Offices Telephone

Central Manak Bhavan 9 Bahadur Shah Zafar Marg 33101 31

NEW DELHI 110002 331 13 75

Eastern l14 C I T Scheme VII M V I P Road ManiktolaCALCUTTA 700054

37 86 62

Northern SC0 445-446 Sector 35-C CHANDIGARH 160036

Southern C I T Campus IV Cross Road MADRAS 600113

Western Manakalaya E9 MIDC Marol Andheri ( East )

BOMBAY 400093

2 18 43

41 29 16

6 32 92 95

Branches AHMADABAD BANGALORE BHOPAL BHUBANESHWAR COIMBATOREFARIDABAD GHAZIABAD GUWAHATI HYDERABAD JAIPUR KANPURPATNA THIRUVANANTHAPURAM

Printed at Printwell Printers Delhi India

832019 12949

httpslidepdfcomreaderfull12949 911

IS129491990

ROCK

All dimensions in millimetres

FIG 4 LAYING CABLES THROUGH ROCKFILL

construction during initial reservoir filling thereadings shall be taken for every 3 m rise or fall

be duly processed and the following graphsprepared

of the reservoir or at monthly intervals Aftertwo years the readings should be taken at every3-monthly intervals except during rainy seasonwhen readings should be taken at monthlyintervals

5 PRESENTATION OF DATA

51 The data from piezometric observations shall

Pore pressure reservoir level and embank-ment height versus time

Pore pressure versus total stress and

The distribution of the above parameteralong with geometry of the place with thecontours and cross sections

832019 12949

httpslidepdfcomreaderfull12949 1011

Standard Mark

The useStandards Act

of the Standard Mark is governed by the provisions of the Bureau of Indian1986 and the Rules and Regulations made thereunder The Standard Mark on

products covered by an Indian Standard conveys the assurance that they have been producedto comply with the requirements of that standard under a well defined system of inspectiontesting and quality control which is devised and supervised by BIS and operated by theproducer Standard marked products are also continuously checked by BIS for conformityto that standard as a further safeguard Details of conditions under which a licence for theuse of the Standard Mark may be granted to manufacturers or producers may be obtainedfrom the Bureau of Indian Standards

832019 12949

httpslidepdfcomreaderfull12949 1111

BiS ia a statutory institution amptamplamphamp under the -ampauamp o f I r d i k q S p e s l d a r i l sc t 986 to promoteharmonious development oftamp campampiampf standardizatioti marking and quality certification of goodsand atampding to connected mstbsrs in ttlre country

_

wdlP

z I

II lsquo1_ rsquo

BIS haq the copyright -dfrsquo amplsquoitamppublittio6 lsquoI$ii amprC of these publications may he reproduced inaxtyrsquoform without the prior -iampion inwriting of BIS This doamp not preclude the free use in thecoampse of implementing the ~standard of nesary details such as symbols and sizes type or gradedesignations Enquiries relating to copyrigtit be addressed to tbe Director ( Publications ) BIS

Revlsioa of Indian Stamdmls

Indian Standards are reviewed periodically and revised when necessary and amendments if any areissued from time to time Users of Indian Standards should ascertain that they are in possession ofthe latest amendments or edition Comments on this Indian Standard may be sent to BIS giving thefollowing reference

Dot No RVD 16 ( 2953 )

Amendments Issued Since Publication

Amend No Date of Issue Text Affected

BUREAU OF INDIAN STANDARDS

Headquarters

Manak Bhavan 9 Bahadur Shah Zafar Marg New Delhi 110002$lsquoelephones 331 01 31 331 13 75

Regional Offices Telephone

Central Manak Bhavan 9 Bahadur Shah Zafar Marg 33101 31

NEW DELHI 110002 331 13 75

Eastern l14 C I T Scheme VII M V I P Road ManiktolaCALCUTTA 700054

37 86 62

Northern SC0 445-446 Sector 35-C CHANDIGARH 160036

Southern C I T Campus IV Cross Road MADRAS 600113

Western Manakalaya E9 MIDC Marol Andheri ( East )

BOMBAY 400093

2 18 43

41 29 16

6 32 92 95

Branches AHMADABAD BANGALORE BHOPAL BHUBANESHWAR COIMBATOREFARIDABAD GHAZIABAD GUWAHATI HYDERABAD JAIPUR KANPURPATNA THIRUVANANTHAPURAM

Printed at Printwell Printers Delhi India

832019 12949

httpslidepdfcomreaderfull12949 1011

Standard Mark

The useStandards Act

of the Standard Mark is governed by the provisions of the Bureau of Indian1986 and the Rules and Regulations made thereunder The Standard Mark on

products covered by an Indian Standard conveys the assurance that they have been producedto comply with the requirements of that standard under a well defined system of inspectiontesting and quality control which is devised and supervised by BIS and operated by theproducer Standard marked products are also continuously checked by BIS for conformityto that standard as a further safeguard Details of conditions under which a licence for theuse of the Standard Mark may be granted to manufacturers or producers may be obtainedfrom the Bureau of Indian Standards

832019 12949

httpslidepdfcomreaderfull12949 1111

BiS ia a statutory institution amptamplamphamp under the -ampauamp o f I r d i k q S p e s l d a r i l sc t 986 to promoteharmonious development oftamp campampiampf standardizatioti marking and quality certification of goodsand atampding to connected mstbsrs in ttlre country

_

wdlP

z I

II lsquo1_ rsquo

BIS haq the copyright -dfrsquo amplsquoitamppublittio6 lsquoI$ii amprC of these publications may he reproduced inaxtyrsquoform without the prior -iampion inwriting of BIS This doamp not preclude the free use in thecoampse of implementing the ~standard of nesary details such as symbols and sizes type or gradedesignations Enquiries relating to copyrigtit be addressed to tbe Director ( Publications ) BIS

Revlsioa of Indian Stamdmls

Indian Standards are reviewed periodically and revised when necessary and amendments if any areissued from time to time Users of Indian Standards should ascertain that they are in possession ofthe latest amendments or edition Comments on this Indian Standard may be sent to BIS giving thefollowing reference

Dot No RVD 16 ( 2953 )

Amendments Issued Since Publication

Amend No Date of Issue Text Affected

BUREAU OF INDIAN STANDARDS

Headquarters

Manak Bhavan 9 Bahadur Shah Zafar Marg New Delhi 110002$lsquoelephones 331 01 31 331 13 75

Regional Offices Telephone

Central Manak Bhavan 9 Bahadur Shah Zafar Marg 33101 31

NEW DELHI 110002 331 13 75

Eastern l14 C I T Scheme VII M V I P Road ManiktolaCALCUTTA 700054

37 86 62

Northern SC0 445-446 Sector 35-C CHANDIGARH 160036

Southern C I T Campus IV Cross Road MADRAS 600113

Western Manakalaya E9 MIDC Marol Andheri ( East )

BOMBAY 400093

2 18 43

41 29 16

6 32 92 95

Branches AHMADABAD BANGALORE BHOPAL BHUBANESHWAR COIMBATOREFARIDABAD GHAZIABAD GUWAHATI HYDERABAD JAIPUR KANPURPATNA THIRUVANANTHAPURAM

Printed at Printwell Printers Delhi India

832019 12949

httpslidepdfcomreaderfull12949 1111

BiS ia a statutory institution amptamplamphamp under the -ampauamp o f I r d i k q S p e s l d a r i l sc t 986 to promoteharmonious development oftamp campampiampf standardizatioti marking and quality certification of goodsand atampding to connected mstbsrs in ttlre country

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BIS haq the copyright -dfrsquo amplsquoitamppublittio6 lsquoI$ii amprC of these publications may he reproduced inaxtyrsquoform without the prior -iampion inwriting of BIS This doamp not preclude the free use in thecoampse of implementing the ~standard of nesary details such as symbols and sizes type or gradedesignations Enquiries relating to copyrigtit be addressed to tbe Director ( Publications ) BIS

Revlsioa of Indian Stamdmls

Indian Standards are reviewed periodically and revised when necessary and amendments if any areissued from time to time Users of Indian Standards should ascertain that they are in possession ofthe latest amendments or edition Comments on this Indian Standard may be sent to BIS giving thefollowing reference

Dot No RVD 16 ( 2953 )

Amendments Issued Since Publication

Amend No Date of Issue Text Affected

BUREAU OF INDIAN STANDARDS

Headquarters

Manak Bhavan 9 Bahadur Shah Zafar Marg New Delhi 110002$lsquoelephones 331 01 31 331 13 75

Regional Offices Telephone

Central Manak Bhavan 9 Bahadur Shah Zafar Marg 33101 31

NEW DELHI 110002 331 13 75

Eastern l14 C I T Scheme VII M V I P Road ManiktolaCALCUTTA 700054

37 86 62

Northern SC0 445-446 Sector 35-C CHANDIGARH 160036

Southern C I T Campus IV Cross Road MADRAS 600113

Western Manakalaya E9 MIDC Marol Andheri ( East )

BOMBAY 400093

2 18 43

41 29 16

6 32 92 95

Branches AHMADABAD BANGALORE BHOPAL BHUBANESHWAR COIMBATOREFARIDABAD GHAZIABAD GUWAHATI HYDERABAD JAIPUR KANPURPATNA THIRUVANANTHAPURAM

Printed at Printwell Printers Delhi India