IS 5878-2-3 (1971): Code of Practice for Construction of ...

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IS 5878-2-3 (1971): Code of Practice for Construction ofTunnels Conveying Water, Part II: Underground Excavation inRock, Section 3: Tunneling Method for Steeply InclinedTunnels, Shafts and Underground Power Houses [WRD 14: WaterConductor Systems]

Gr3

IS : 5878 (Part IUSec 3) - 1971(Reamrmed 2005)

Indian StandardCODE OF PRACTICE FOR

CONSTRUCTION OF TUNNELSCONVEYING WATER

PART II UNDERGROUND EXCAVATION IN ROCK

Section 3 Tunnelling Method for Steeply Inclined Tunnels,Shafts and Underground Power Houses

Fourth Reprint AUGUST 2007(Incorporating Amendment No. land Including Amendment No.2)

UDC 624.191.2

© Copyright 1977

BUREAU OF INDIAN STANDARDSMANAK BHAVAN, 9 BAHADURSHAH-~AFAR MARG

NEW DELHI 110002

August 1971

IS I 5878 ( Part IJ/Sec 3) .1971




Sectlon:l Tunnellins Method for Steeply Inclined Tunnels.Shafts and Und.,..round Power Houses

W~ter Conductor Systems Sectional Committee, BDC 58

ChainNmSBBI P. M. MAN.

R~ayam,Pedder Road, Bombay-26

lUpramtin,Damodar Valley Corporation, DhanbadTamil Nadu Electricity Board, Madr..

MembersIUlll N. M. CRAXBAVOBTY:HJEI' CON8TBOCTION ENGINEER

SUPE.BINTB~DINQ ENOINZEB( TEOHNIOAL/CIVIL) (J4llmaall)

eRIEI' ~NQINEBR (CIVIL) Andhra Pradesh State Electricity Board, HyderabadSU?1tBINTBNDINO ENOI.EBB

( CIVIL AND INVESTIOATIONCnc.CLE ) ( .,4/''''''411 )

CUIEI' ENGINEER (CIVIL) Kerala State Electricity Board, TrivandrumDEPUTY DIREOTOR ( DAMS I ) Central Water at Power Commiuion. N~w DelhiDIREcr08 lniption at Power Reaearch Institute, Amritaar,

DR GAJINDI:B SINOH (~ltm&tJI')SUBl D. N. DUTTA Assam State Electricity Board, ShillongSRRI O. P. DuT'r.A Beaa Project, Nanlal Township

SKB1 J. S. SUlIOBOTA (JflumtJI, )SRal R. G. GANDIU The HindUitan Construction Co Ltd, Bombay

SBBI M. S.DBWAN (Ai",JUJU)'SB.I K. C. GB08AL Alokudyog Cement Service, New Delhi8..J B. S. K.ua. Irrigation a. Power Department, Government of

Maharaabtra88m R. S. K.u.J:(AI,,,,,.,, )

S.BI V. S. Kal8BNAI'\VAJlY Geological Survey of India, CalcuttaS.81 K. S. S. Me.THY Ministry of IrrigatioD .. PowerSOl Y. G. P.ftL • Patel Engineeriol Co Ltd, Bombay

SSJU C. K. CaOKISJ ("AlllnllJl')SUI P. B. PATJL Gammon India Private Ltd, BombaySRRI A. R.1lA.JOBUa R.J. Shah at Co Ltd, BombaySBRI G. S. SRIVAN1f. Public Works It Electridty Department, Government

otMy.oreS••I S. G. BALAKO'NDBY (All",..,,)

( COftlinutd on/Nt" 2)

BUREAU. OF INDIAN STANDARDSMANAK BHAVAN, 9 BAHADURSHAH ZAFAR MARG

NEW DELHI 1100021

IS 15878 (Put DISee 3 ) ·1871

( Conlinu,Jj,.", /Jal' 1 )

M",.lHrsSaOBETABYSDJt.lJ. E. V~Z

SHRtJ. WALT.a ( AI,,,.,,.,,)Saal D. AJIT'BA SIMIU.

Director (Civ EoSS )

&/J,,.,,'u.,CentraJ Board or Irri;ation It Power, New DelhiPublic Works Department. Government of Tamil

Nadu

Director General. lSI (&-offido MnnIJ" )

SImttJrySSRI BIMLMB KUHAR

A••i.tant Director (Civ Engg), lSI

Panel for Construction of Tunnels, BDC 58: P2

CtmVnUrSHIll B. S. KAJ'BB Irrigation & Power Department. Government of

MaharashtraMlmblll's

SHB1 R. S. KALD (AI",nal, toShri B. S. Kapre )

SUBI C. K. CBOK8BI Patel Engineering Co Ltd. BombayDBPUTY DIRKCTOB ( OAKS I ) Central \\'ater & Power Commission. New DelhiSam M. S. DBWAN The Hindustan Construction Co Ltd, BombaySum K. C. GB08AL A-lokudyogCement Service, New Delhi ..Sam A. R. RAIOHO. R. J. Shah &: Co Ltd, BombaySaaI K. SBAJIIA RAO Ker.ln State Electricity Board. Trivandrum

SHIU A. S. NAaAYANAN (AII"'"d')Saal G. N. TANDOH Irrigation Department, Goverament or Uttar Pradesh

2

AMENDMENT NO. 2 MARCH 1993TO

IS 5878 ( Part 2/Sec3) : 1971 CODE OF PRACfICE FORCONSTRUCfION OF TUNNELS CONVEYING WATER

PART 2 UNDERGROUND EXCAVAll0N IN ROCK

Section 3 Tunnelling Method for Steeply Inclined Tunnels, Shaftsand Underground Power Houses

( Page 4, clause 0.4 ) - Insert the following at the end:

'Part 7 Grouting'

( Page 4, clause 0.5 ) - Delete and renumber 0.6 as 0.5.

(Page 4, clause 3.~ ) - Substitute 'IS 4756 : 1978' for 'IS: 4756 - 1968'

( Page 4, foot-note) - Insert '( rust revision )' at the end of the foot-notemarked with 't' mark.

(Page 10, clause 7.5.2 ) - Substitute 'IS 807 : 1976' for 'IS: 807 - 1963'.

(Page 10,/oot-note ) - Insert '(firs: revision )' at the end.

(RVD 14)

.1

1815878 ( Part II/Sec 3). 1971




Section 3 Tunnellinl Method for Steeply Inclined Tunnels,. Shafts and Underaround Power Houles

o. FOR E W 0 R D

0.1 This Indian Standard (Part II/Sec 3) was adopted by the IndianStandards Institution on 15 March 1971, after the draft finalized bythe Water Conductor Systems Sectional Committee had been approvedby the Civil Engineering Division Council.

0.2 The construction of tunnels involves a large number of problemsbecause of the great longitudinal extent of the work and many kinds ofconditions are encountered which for maximum economy should be treateddifferently. In view of this it has been appreciated that it should be futileto prepare a rigid set of rules or procedures which can be enforced withoutleaving any latitude for the exercise of discretion by the site engineer.The aim of this standard is to summarize the well known and provedprinciples and to describe the commonly used procedures and techniquesfor providing guidelines which would permit the site engineer to use hisdiscretion. This section deals with special features involved on tunnellingsteeply inclined tunnels. shafts and underground power houses. TheIndian Standard code of practice for construction of tunnels ( IS: 5878) isbeing publis~~d in parts and Part II in sections.

O.S Sometimes vertical or inclined shafts are required to be constructed toserve as ccnstruction adiu or as permanent works,suchal approachtunnels, pressure shafts, ventilation tunnels and cable tunnels for underground works like power station. Tunnelling operations described inPart II, Section 1 are generally applicable to such shafts and tunnel••However, some special features are involved in construction of steeplyinclined tunnels, shaft. and underground power stations and only suchspecial features are covered in this section. Inclined shafts are also termedas inclined tunnels.

0.4 Other parts of this standard are as follows:Part 1 Precision survey and Betting outPart III Underground excavation in soft strata

IS t 5878 (Part DjSec 3 ) -1971

Part IV Tunnel supports

Part V Con~et~ liningPart VI Steel lining

0.5 This standard is one of a series of Indian Standards on tunnels. Otherstandards published so far in the series are:

IS: 4081-1967 Safety code for blasting and related drilling operations18:4137-1967 Safety code for working in compressed airIS: 4756·1968 Safety code for tunnelling workIS: 4800 (Part II )-1968 Code of practice for design of tunnels con

veying water: Part II Geometric design (Shlc.e revised).lS :4880 (Part III )-1960 Code of practice for. design of tunnels

conveying water =- Part III Hydraulic design (Since revised ).IS: 4880 (Part 1\' )-1971 Code of practice for design of tunnels con-

veying water ePart IV Structural design of concrete lining in rock

0.6 For the purpose of deciding whether a particular requirement of thisstandard is complied with, the final value. observed or calculated, expressing the. result of a test or analysis, shall be rounded off in accordance withIS: 2-1960 fJ _ The number of significant places retained in the r-oundedoff value should be the same as that of the specified value in this standard.

1. SCOPE

1..1 This standard (Part II/Sec 3) deals with special features involved intunnelling operations on steeply inclined tunnels, shafts and undergroundpower houses. However, tile tunnelling operations described in Part II,Sections 1 and 2 of this standard are generally applicable to such worksalso.

2. SETTING OUT

2.1 $etting out of works shall be done in accordance with IS: 5878(Part 1)-1971t.S. SAFETY PRECAUDONS

3.1 Adequate safety precautions shall be taken in accordance withIS: 4756-1968;_

-J(.ules for rounding oft' numerical values ( ,trIiJItl ).'Code of pr~ctice (or construction or lunnela: Pare I Precision lurvey and setting out.:Sar~ty code for tU1}Jlelliogwork.

4

IS .5878 ,(:part DjSec :4). 1971

4. METHOD OF ATTA.CK FOR VERTICAL SHAFTS

4.1 Vertical shafts may be sunk usually from top to bottom but when accessat tile bottom is available the following methods may be more beneficialfor excavation. The method to be used will also depend upon geology t

size and seepage of water:

a) A small pilot of about 2to 3 m dia may be first excavated from topto bottom and then the shaft may be widened throwing the muckdown the pilot shaft, which may be mucked from the bottom bysuitable mucking equipment. .

b) Instead of sinking a pilot from the top, an 8 to 10 em dia hole maybe drilled from top to bottom. Through this hole 2. cage may besuspended to the bottom by installing a winch at the top. Withthe help of this cage, a small riser of about 2 m diameter may beexcavated upwards to serve as a pilot shaft. Then as in the methodgiven at (a), the shaft may be widened and the muck throwndown.

c) Burn type pattern of long holes may be drilled throughout theentire depth of the shaft by powerful wagon drills and by usingguide tubes to see that deviation of holes is minimum. Afterdrilling, these holes may be blasted by charging them from top andblasting progressively upwards,

5. ldETHOD OF A.TTJ.joCJ{ l?OR JNCLINED SHAFTS OR TUl\!l\fELS

5.1 Inclined shafts or tunnels may be sunk from top to bottom or if accessis available, from bottom to top or from both top and bottom. If thedepth of the shaft is more than 300 m generally an intermediate adit maybe provided for opening additional working faces. The method to beused will also depend upon geology, size and seepage of water. .

5.2 The following are the general methods for sinki~g inclined tunnels. and/or shafts:

a) From bottom upwards with full face,b) From top downwards with full face, andc), From bottom upwards with pilot headios and widening from toP

downwards.

5.2.1 FromBottom UJlWtUds wjlh Atll FlU, - Thls method consists of raUing the ahaft from the bottom and as such, the muck after blasting rollsdown by gravity. Therefore, proper arrangements shall be made to protect the air and water mains and ventilation ducts. The shafts may beusually divided into two parts as shown in Fig. 1 10 that the services arekept in the top part, while the muck rolls down from the other Part.Drilling platform and other thiDgs shall be winched up by some suitable

5

IS*5878 (Part II/Sec 3 ).1971

arrangement and drilling shall be carried out from a platform. Drillirq;shall be done with rock drills and pushers and blasting may be done asusual. This method has the following advantages and disadvantages:

a) J~dvantQges

1) Muck slides along the slope and collects at the bottom fromwhere it is loaded by leaders.

2) The quantity of explosive required is slightly less than what isrequired for the other method.

3) If there is underground water no pumping is necessary,

b) Dlsadoantages1) Hoisting the material up the raise every time and going up is

more troublesome, as every thing lias to go on a steep slopeagainst gravity.

2) Scaling after blasting is more difficult.3) Ventilation has to be very powerful, otherwise the gases after

blasting take more time to go out as they have tendency to goupward,

AIR PIPE

rTEMPORARV/ PLATFORt-t

'. ~rTOP AREA FOR SERVICES

/\ -VENT PIPE

OO\VElS FORPlAT~ORt...

,rBOTTOM AREA FOR MVCK

1

1;'1"0. 1 P,..urrrrox IN Bor-rou U;:'~'VA.RO~ EXCAV1.TION wrrn FULL FAC[~

.5.2.2 From TOI' Doumumrds with Full Face- In this method, all theoperations are carried out from top downwards, as in sinking a verticalshaft (Sl.t 4.1). Tile sinking of the inclined Jhaft is more difficult thansinking a vertical shaft. Drilling and blasting may be carried out as

6

IS:5878 (Part D/Sce 3 ) .1971

usual. The general arrangements may be as shown in Fig. 2. Thismethod has the following advantages and disadvantages:

a) Adl!anlages1) Going down the shaft and taking the equipment is easier.2) Regular trolley track can be laid at the bottom so that Ute

material and men can be winched up easily after every operation.S) Removal of gases takes less time.4) All the services are not liable to be damaged by mucking or

blasting.

b) Disaduantages1) The muck is to be loaded manually, as such the progress will

be slower than by the method given in 5.2.1.2) If underground water is met with, dewatering will be

difficult.

RAIL

HOPPER FOR HOISTING THE ~~UCK

TROLLEY FOR TAKING OUT t.tUCK

FIG.2 EXCAVATION FROll Top DOWNWARDS WITH FULL FACE

5.2.3 From Bot/om Upwards toitl: Pilot Heflding- This method is adoptedwhen the size of the shaft is quite big. First a pilot heading at the lowerlevel is driven from bottom upwards as shown in Fig. 3. After the pilotis complete, widening is started from top and carried down, 'l11us,.inboth the operations the muck is allowed to fall down so that it can slidealong the slope by gravity up to the bottom of the shaft, from where it isremoved by loaders. This method has most of the advantages of themethods given in 5.2.1 and 5.2.2 besides the overall cost might work outcheaper.

Nom - With the development of special rigt' which climb atong the tunnel/shaftfrom bottom upward, and are capable of drilling large diameter boles' the bottomupward method i. becoming easier. The long hole method given in 4.1 (c ):ean alsobe used.

7

IS a5878 (Part BIBee 3) .1971

TOP PORTION DRIVENFROM TOP DOWNWARDS

PILOT HEADING DRIVENFROM BOTTOM UPWARDS

Flo.3 ExCAVATION FRO},! BonOM UPWARDS WITH PILOT HEADING

6. DRILLING6.1 Drillinp pattern for the sbaft does not vary as much as for the tunnel.The followmg drilling patterns may be used:

a) The most commonly used is centre wedge cut for' square andrectangular sections (see Fig. 4);

b) For circular sections, sometimes wedge cut or pyramid. cut is alsoused; and

c) W11en shafisare very large, drilling may be done in alternate steps(see Fig. 5). *' .

FlO. 4 CBNTRAL WEDGE CoT

8

FlO. 5 STEPS FOR DRILUHGLAROE SHAFTS

IS: 5878 (Part It/Sec 3 ) • 1971

7. MUCKING

7.1 There are various methods of hoisting muck through shafts. Theselection of method depends on the size of the shaft and the progressdesired. The mucking through the shaft may be divided into two categories, namely (a) mucking for sinking the shaft and (b) mucking of thetunnel driven through the shaft.

NOTE - In the first case, actual bJ~sting takes place in the shaft and, therefore, noequipment can be kept in the shaft during blasting. Therefore, the arrangements ofmucking have to be done accordingly. III the latter case, as the blasting takes place inthe tunnel, the .h3rt is free and; therefore, permanent type of equipment can beinstalled in the shaft for mucking.

7.1.1 General design and layout of hoisting plant is influenced by manyfactors. such as size, depth of shaft, space available on the top surface, sizeand length of the tunnel, type of ground and method of hoisting muck.

7.2 l\fucL.i.ng of Vertical Shafts-For sinking shaft, the muck may beremoved manually in the beginning for about 3 m or 30. Thereafter,muck may be hoisted by temporary mechanical arrangements, such asthree-legged derrick or crane, till- other permanent arrangements: such asheadgear, fixed or movable crane, sliding skip are installed.

7.3 Mucking of Inclined Shafts 01- Tu.nnels- When sinking is beingdone from top to bottom, winches have to be used for hauling muck intosuitable skips running on trolley track. If the shaft is being raised t themuck may be pushed down which may be achieved by gravity by using ascrapper.

7.4 Sp~clal Methods and Eqw!Jmcct- Sometimes special methodsand equipment may be used for working from bottom upwards. Invertical shafts a central hole may be drilled through and a cable is passedthrough the hole to support the platform ( cradle ). This platform may behauled up and down as required by means of a winch. During blastingthe cradle shall be removed to a safe place.

NO'1'&- For inclined and vertical .hafts a travelling unit has been developed.Thi. moves OD a mono rail IUpported (rom the top (or aide) by meanJ or removablerock belts.

1.5 PrecaadoDs

7.5.1 Head Fra"" - The head frame (including hoists. cables, etc) shallbe preferably of steel structure and properly designed with sufficient

, head room and strong enough for possible overload and impact due tosudden drops.

9

IS r 5878 (Part D/5ec 3 ) ·1971

7.5.2 HoiJt Efuipmmt- It shall be thoroughly i~cted at least once aweek and maintained in first class condition. Suitable standby powersupply arrangement or alternate means of wor~ing the hoist mechanically(u, IS: 807-1963·) shall be provided. A limit switch or automatic brakeshall be provided OD the hoist to' control speed.

7.5.2.1 There shall be a fencing round the shaft opening at least90 em high and it shall comprise. two rail guards and also a top board,15 em high to prevent material from falling in. The gate provided theresball be closed except when used for entering or leaving the shaft oremptying the buckets. The gate should preferably be automatic.

7.5.3 .d'USI Throug" SluJfts-Penons shall not be lowered or raised inbucket used for mucking.

7.5.3.1 A special cage or a bucket sull be used for lowering or raisingpersonnel during the sinking of a shaft. For emergency use, strong laddermade out of wire rope shall be provided on one side of the shaft. Afterthe shaft i••unk, a suitable arrangement for the workman shall be madein the shaft for access to the shaft and the tunnel.

7.5.4 Sig1ltlu-Reliable means of communication, such as bells orwhistles or electric signals shall be maintained at all times between thebottom of the shaft and the surface and telephones used, wherever possible,

7.5.4.1 Any code of signals used shall be kept conspicuously pastednear workplace or entrance.

8. TUNNELLING METHODS FOR LARGE TUNNELS

8.1 The tunnelling methods described in other sections shall be generallyapplicable.

i.2 The methods of attacking the faces or tunnel depends on 'the type ofrock strata available, size and shape of tunnel and the equipment available.The following methods may be generally used:

a) Full FGu- When the rock strata is hard and massive, the tunnelsmay be attacked full face. .

b) TO/' H,_a, lind Bmchi,.,- This method may be used when thequality of the rock i. lea sati.Cactory. After driving top headingto the full section, the arch may be concreted iCfound necessary tosupport the rock before taking out the. bench.

c) Multipu Drqfi-Thil method may be used when the strata of rockis poor.

-COde or practice for· daiga, manufacture, erection and lellin. (.t~ctural portion)of craftfl aDd hollta.

10

IS 15878 (Part "D/See 3) ·1971

9. TUNNELLING METHODS FOR UNDERGROUND POWERHOUSE •

9.1 For starting work in underground power station, invariably one or twoaccess tunnels may be provided. The position, location and the numberof access tunnels will depend on the topography of the area, the size ofthe power station and time available for its construction; while theirsizes will depend on the mucking equipment to be used and machinery to betaken inside for installat ion.

9.2 As the width and height of a power station will be bigger thanmost tunnels, the normal practice is to excavate first the top portion of thepower station up to the arch and concrete the arch. This is necessary torender the whole working area safe from any rock falls, which are likely totake place due to wider and flatter arches. After the arch is concreted,the benches may be removed in one or more operations, depending on theheight of power house and the nature of rock.

11

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