GEO-TECHNICAL ENGINEERING DIRECTORATE

GEO-TECHNICAL ENGINEERING DIRECTORATE

Draft specifications have been prepared by Geo-technical Engineering Directorate

of RDSO for various items related to Tunnel construction- tunnel support system,

waterproofing, grouting etc., i.e. SN-Bolts/Rock Bolts, Self Drilling Anchors, Self Drilling

Anchors for Pipe Roofs, Water Expandable Rock bolts/Water Expandable, Glass

Reinforced Plastic Bolts, PVC Waterproofing Membrane, Non-Woven Polypropylene

Geotextile, PU/PUR grout, Cement Grout for Rock bolts.

These Draft Specifications were uploaded on RDSO website

www.rdso.indianrarilways.gov.in for comments/suggestions from industries / individuals

having technical experience and expertise in respective fields with a view to improve

upon the specifications. The last date to submit comments & suggestions on the Draft

Specifications was 31.03.2018.

A reasoned document containing all the comments/suggestions with reasons for

accepting / rejecting the same has been prepared and attached as annexure-A, B & C.

Final Draft specifications based on the above accepted changes has also been prepared

and attached herewith.

Comments/suggestions are invited from industries / individuals having technical

experience and expertise in respective fields with a view to improve upon the following

specifications. Comments/suggestions shall be suggestive in nature, which shall not

alter the basic objective of the specification. Technical reasons supported with enough

documentary evidence, preferably in the fields of Railway applications must be enclosed

with offered comments/suggestions.

Firms/industries/individuals are requested to submit their comments & suggestions by

23.04.2018 to the contact details as mentioned below:

Mr. Sameer Singh, Joint Director/GE

Research Designs & Standards Organisation (RDSO)

Ministry of Railways,

Manak Nagar, Lucknow-226011

Uttar Pradesh, India

Email- [email protected], [email protected]

Phone No.-0522-2465721

http://www.rdso.indianrarilways.gov.in/

mailto:[email protected]

mailto:[email protected]

Annexure - A

Reasoned Document

S. No.

Clause of RDSO Specification

Comments/Suggestions from firm DSI-Bridgecon India Pvt. Ltd.

RDSO’s Comments Remarks

1. Several places in specification

Kindly Remove All References To Word

Swellex As It Is A Brand Name Of Water

Expandable Rock Bolts Made By Atlas Copco

and mentioning one brand gives Atlas

Copco an undue advantage over us, Our

Brand name for Water Expandable Rock

Bolts is OMEGA® BOLTS. Please refer

below link to check the trademark

information of SWELLEX

https://www.trademarkia.com/swellex-

73582973.html

As suggested by the firm the word

“Swellex” is the brand name of

Water Expandable Rock Bolts made

by Atlas Copco and the document

received from the link mentioned by

the firm also depict the same.

Hence, to avoid any ambiguity the

word “Swellex” have been removed

from the specification.

https://www.trademarkia.com/swellex-73582973.html

https://www.trademarkia.com/swellex-73582973.html

2. 1. SN-Bolts/ Rock Bolts:

These are made of

deformed reinforcing

steel with a corrugated

surface. Of which one

end shall be fitted with

a suitable thread to fix

anchor plate with nut.

The steel rods shall be

corrosion protected.

These are made of hot rolled

fully threaded reinforcing steel

with a corrugated surface. The

bar should be threaded along

the entire length of bolt to take

care of Geotechnical conditions

which demand a shorter or a

longer bolt at site (eg. Dywidag

GEWI® Bars)

These specifications are for SN Bolts

only, made of deformed steel bars

and not for fully threaded bars.

One end of which should be fitted

with suitable length of threads to fix

anchor plate with nut so as to give

proper anchorage of bolt to the rock.

3. 1.3. (f) Anchor Plate of

size 200mm x 200mm

(min) and thickness of

plate 10mm (min) is

generally used based

on support necessities.

The shape shall allow a

uniform seat over rock,

if the bolt is not

installed exactly

perpendicular to the

surface.

Domed Anchor Plate of size 200mm x

200mm (min) and thickness of plate 10mm

(min) is generally used based on support

necessities. The shape shall allow a uniform

seat over rock, if the bolt is not installed

exactly perpendicular to the surface.

Anchor Plate of size 200mm x

200mm (min) and thickness of plate

10mm (min) is generally used based

on support necessities. The shape

shall allow a uniform seat over rock,

if the bolt is not installed exactly

perpendicular to the surface.

Wherever, the base of rock is not

flat any suitable shaped plate like

domed, hemispherical etc. can also

be used as per the site conditions to

allow a uniform seating.

Annexure - B

S. No.

Clause of RDSO Specification

Comments/Suggestions from firm STP Ltd.

RDSO’s Comments Remarks

1. Clause No. 7.2 ShaliPlast Shotcrete L is a chloride free

accelerator for quick setting and

waterproofing compound of Sprayed

concrete or mortar even on a wet surface

allows overhead spraying and reduces

rebound.

The firm has not made any

comment/suggestion on the

specification.

Hence, no changes have been made.

2. Corrosion inhibitor For Tunnel Concrete

Shell

ShaliPlast LW++ is an integral liquid

waterproofing compound, which protects

concrete internally from water ingress as

well as saves the re-bars of reinforced

concrete and mortar against chloride

induced corrosion. The unique bi-polar

compound migrates through concrete

during curing process and puts a passive

layer over re-bars to stop chloride corrosion.



specification.


3. Clause No. 7.2 On top of PVC membrane Place Water Bars

to make Compartment 250 Sq m followed

by Place Injectable Hoses, terminate hoses

into junction box for Future injection during

Leakage.

The firm has given its product

“ShaliPVC” details and its properties.

The specifications have been framed

for the waterproofing system

consisting of a protective layer of

geotextile and one layer of PVC

waterproofing membrane.



specification of the same.


4. Clause No. 9.3 ShaliGrout PU a low Viscous Liquid, Which

React with water to form a swelling resilient

strong adhesive mass. Inject under

pressure into leaking structures to form a

permanent Flexible water barrier through

Polymerization.

Drill holes at 45 0c angle to Intersect the

crack approx. 100 mm below concrete

surface. Drill holes alternately on opposite

sides of the cracks allowing 200mm

distance.

Inject Shali Grout PU.

The firm has given its product

“ShaliGrout PU” details and its

properties.



specification.


Annexure - C

Some codes mentioned in the specification have been superseded. Hence, these codes have been replaced and included

in the draft specification. Latest version of all the relevant codes should be used. The changes are as listed below:-

S. No. Previous version of codes Latest version of codes

1. BS EN 1537 : 2000- Execution of Special

Geotechnical work- Ground Anchors

BS EN 1537 : 2013- (Latest Version)

2. BS EN 10002-1 – Metallic Material- Tensile

Testing – Part 1 (Renumbered)

BS EN ISO 6892-1 : 2016 (Latest Version)

3. BS EN 10045-1 - Metallic materials — Charpy

impact test — Part 1(Renumbered)

BS EN ISO 148-1 : 2016 (Latest Version)

4. Euro Norms- 6 & 12 – Metallic materials - Bend

Test (Renumbered)

BS EN ISO 7438 : 2016 (Latest Version)

FINAL DRAFT SPECIFICATIONS

1. SN-Bolts/ Rock Bolts:

Store-Norfors-Anchors (named after the first place of installation) popularly

known as SN-Anchors are mortar embedded concrete reinforcement steel

anchors and are used for rock reinforcement in underground Mining and

Tunneling.

These are made of deformed reinforcing steel with a corrugated surface. One

end of which should be fitted with suitable length of threads to fix anchor plate

with nut so as to give proper anchorage of bolt to the rock. The steel rods shall

be corrosion protected.

1.1 Uses:

SN-Bolts/ Rock Bolts are used mainly as a temporary support in tunnels for

Ground support, Rock stabilization and Anchorages in rock.

1.2 Installation Procedure:

a) Drilling of Boreholes

b) Filling of the borehole with grout

c) Manual insertion of SN-Anchors into the pre-filled boreholes, fixation in the

borehole using a wedge or similar device

d) Proper curing is to be done

e) Tensioning of the bolt’s head by tightening of the nut

1.3 Design Considerations and Specifications:

a) The ground is a vital element of the ground anchor system; therefore a good

quality geotechnical investigation is essential. Various parameters to be

considered during geotechnical investigations should include Classification of

rocks (Geometry of discontinuities, unit weight, degree of weathering, Index

test), Rock stratification, Unconfined compression strength of intact rock,

Shear strength and deformability of rock mass, Permeability, Ground water

conditions, Corrosion potentials of rock and ground water etc.

b) Moreover, the design of the anchor system is based on rock parameters and

the geometry of the anchor arrangement. Where changes in the anchor

locations, spacing’s or inclinations are proposed, appropriate studies or

proving tests should be undertaken to demonstrate the suitability of such an

arrangement. The design of the anchor should consider the following-

i. Loads and constraints of loading imposed by the anchors on the overall

structure

ii. The way in which the loads will be applied to the anchor during its

designed life i.e. static or dynamic

iii. The load distribution of the anchor arrangement on the structure during

stressing and during the design life of the structure

iv. The interface between the anchor and the structure to ensure structural

stability

v. The consequence of anchor failure during stressing and thereafter.

c) The diameter and tensile strength of bolt and also arrangement (number,

spacing etc.) of rock bolts to be used may vary according to design. The

diameter of rock bolts depend on the mass of the rock to be supported by each

rock bolt and the force of resisting shear in the bedrock.

d) EN 1997-1 – Geotechnical Design-Part 1: General Rules and BS EN 1537: 2013-

Execution of Special Geotechnical work- Ground Anchors may be followed for

all geotechnical designs, installation of Ground Anchors. DIN 1054:2005-01 –

Ground verification of the Safety of Earthworks and Foundations is also being

used for geotechnical designs for ground anchors.

e) Generally, SN- Bolts having minimum diameter of 25 mm, with a yield load of

200 kN (Min) for steel grade Fe 415 & yield load of 245 kN (Min) for steel

grade Fe 500 are used as a temporary support in tunnels. These are the lower

limit of specifications & may vary as per actual site conditions and design

requirements; mechanical properties/requirement accordingly can be adopted

from the relevant codes (IS-1786) (Annexure-I).

f) Anchor Plate of size 200mm x 200mm (min) and thickness of plate 10mm (min)

is generally used based on support necessities. The shape shall allow a

uniform seat over rock, if the bolt is not installed exactly perpendicular to the

surface. Wherever, the base of rock is not flat any suitable shaped plate like

domed, hemispherical etc. can also be used as per the site conditions to allow

a uniform seating.

g) The yield loads of the bolt get transferred through thread to nut, washer,

anchor plate and coupling etc. Hence, these should also be designed

accordingly.

h) SN-Bolts/Rock bolts should conform to Indian Standard code IS-1786: High

Strength Deformed Steel Bars and Wires for Concrete Reinforcement-

Specification. Code has mentioned the mechanical properties of high strength

deformed bars (Annexure-I) and various tests viz. Tensile test, bend test,

Rebend test and Retest norms.

i) The tensile strength, percentage elongation, percentage total elongation at

maximum force and 0.2 percent proof stress of bars/wires shall be determined

as per IS: 1786.

j) The bend test should be performed in accordance with the requirements of IS

1599 and the mandrel diameter for different grades shall be as specified in

Table 4. The test piece, when cold, shall be doubled over the mandrel by

continuous pressure until the sides are parallel. The specimen shall be

considered to have passed the test if there is no rupture or cracks visible to a

person of normal or corrected vision on the bent portion.

k) The rebend test should be performed in accordance to IS: 1786. The test

piece shall be bent to an included angle of 1350 using a mandrel of appropriate

diameter. The specimen shall be considered to have passed the test if there is

no rupture or cracks visible to a person of normal or corrected vision on the

rebent portion.

l) The Retest should be performed in accordance to IS: 1786-2008. If any one of

the test pieces first selected fail to pass any of the tests specified in this

standard, two further samples shall be selected for testing in respect of each

failure.

m) Pull out test on Rock Bolts shall be performed as per IS: 11309 – Method for

conducting Pull-Out Test on Anchor Bars and Rock Bolts.

- Minimum three pull out tests shall be conducted in one rock formation as

mentioned in clause 4.8 of IS: 11309 or as per the instructions of Engineer-

in-charge.

Annexure-I

Sl No. Property Fe 415 Fe415 D Fe415 S Fe 500 Fe500 D Fe500 S Fe550 Fe550 D Fe 600

1 2 3 4 5 6 7 8 9 10 11

i)

0.2 percent proof

stress/ yield

stress, Min.

N/mm2

415 415 415 500 500 500 550 550 600

ii)

0.2 percent proof

stress/ yield

stress, Max.

N/mm2

540 625

iii)TS/YS ratio,

N/mm2

>1.10, but TS

not lessthan

485 N/mm2

>1.10, but TS

not lessthan

500 N/mm2

1.25

>1.08, but

TS not less

than 545

N/mm2

>1.10, but

TS not less

than 565

N/mm2

1.25

>1.06, but

TS not less

than 555

N/mm2

>1.08, but

TS not less

than 600

N/mm2

>1.06, but

TS not less

than 660

N/mm2

iv)

Elongation

percent, min. on

gauge length 5.65

√A , where A is the

cross-sectional

area of the test

piece.

14.5 18 20 12 16 18 10 14.5 10

v)

Total elongation at

maximum

force, percent,

Min, on gauge

where A is the

cross-sectional

area of the test

piece

5 10 5 8 5

Table 3 Mechanical properties of High Strength Deformed Bars and Wires (AS per IS: 1786-2008)

TY/SY Ratio refers to ratio of tensile strength of the 0.2 percent proof stress or yield stress of the test piece.

2. Self-Drilling Anchors:

Self-Drilling Anchor bolts are a combined system of rock bolt and drill rod. During

drilling, the bolts is used as the drill rod fixed with a drill bit, rod and bit remain

in the hole as a rock bolt, which is grouted through the flushing hole. In case of

collapsing boreholes, this system still enables the installation of rock bolts for

very common flexible rock support to anchor the fractured rock mass in the

tunnel and gives the strength and stability to the ground.

2.1 Use:

Self-Drilling Rock Bolt is a rock-bolting system based on fully coarse threaded

hollow bar. It is especially recommended for the following applications:

a) Roof and wall bolting as a temporary support in tunnels.

b) All ground conditions. Self-Drilling Rock Bolts do not require pre-drilling a

hole, therefore making it usable even in soft rock conditions.

c) Self-drilling bolts shall be used in ground conditions where the effective

installation of other types of rock bolts is impossible.

d) For loose ground/ fractured rock conditions, where drill holes collapses

immediately during the drilling, the Self Drilling Anchors can provide

immediate stabilization of the opening.

e) It shall be grouted through the flushing hole immediately after completion

of the drilling operation or simultaneously with the drilling as required.


a) Drilling, grouting, and anchoring, in one operation. The hollow steel anchor

rod also acts as a grouting pipe to ease set up.


a) The ground is a vital element of the ground anchor system; therefore a

good quality geotechnical investigation is essential. Various parameters to

be considered during geotechnical investigations should include

Classification of rocks (Geometry of discontinuities, unit weight, degree of

weathering, Index test), Rock stratification, Unconfined compression

strength of intact rock, Shear strength and deformability of rock mass,

Permeability, Ground water conditions, Corrosion potentials of rock and

ground water etc.




proving tests should be undertaken to demonstrate the suitability of such

an arrangement. The design of the anchor should consider the following-

i. Loads and constraints of loading imposed by the anchors on the

overall structure



iii. The load distribution of the anchor arrangement on the structure

during stressing and during the design life of the structure

iv. The interface between the anchor and the structure to ensure

structural stability



spacing etc.) of rock bolts to be used may vary according to design and site

requirements. The diameter of rock bolts depend on the mass of the rock to

be supported by each rock bolt and the force of resisting shear in the

bedrock.

d) EN 1997-1 – Geotechnical Design-Part 1: General Rules and BS EN 1537-

2013- Execution of Special Geotechnical work- Ground Anchors may be

followed for all geotechnical designs, installation of Ground Anchors. DIN

1054:2005-01 – Ground verification of the Safety of Earthworks and

Foundations is also being used for geotechnical designs for ground anchors.

e) Generally, Self-drilling Anchors/bolts having minimum diameter 32 mm with a

minimum yield load of 200 kN are used for Rock bolting/ Face bolting as a

temporary support in tunnels. These are the lower limit of specifications &

may vary as per actual site conditions and design requirements; mechanical

properties/requirement accordingly can be adopted from the relevant codes

(EN-10083-1) (Annexure-II).

f) Adverse interactions of anchorages should be avoided, by keeping a space

not less than 1.5 m between them, if possible.

g) The yield loads of the bolt get transferred through thread to nut, washer,


accordingly. The rolled thread should be in accordance with ISO 10208.

h) Manufacturing of Self-drilling Anchors should conform to BS EN-10083-1

“Steels for quenching and tempering - Part 1: General technical delivery

conditions”.

i) For all types of Self-drilling Anchors, the anchor head shall be designed in

accordance to BS EN 1537-2013, and should be able to accommodate

deformations, which may occur during the design life of the structure.

j) Corrosion protection of Self-drilling Anchors should comply with Para 6.9 of

BS EN 1537-2013 as required.

k) Tensile test of Self-drilling Anchors is done in accordance to BS EN ISO 6892-

1: 2016. The test involves straining a test piece in tension, generally to

fracture, for the purpose of determining one or more of the mechanical

properties i.e. percentage elongation, tensile strength, yield strength, upper

yield strength etc.

l) Impact test of Self-drilling Anchors should be done is done in accordance to

BS EN ISO 148-1: 2016. The test consists of breaking by one blow from a

swinging pendulum, under conditions defined in code above. The energy

absorbed is a measure of the impact strength of the material.

m) Pull out test on Self-drilling Anchors should be performed of on the basis of

IS: 11309 – Method for conducting Pull-Out Test on Anchor Bars and Rock

Bolts.


mentioned in clause 4.8 of IS: 11309 or as per the instructions of

Engineer-in-charge.

Annexure-II

Upper Yield

Strength,

Re

min.

Mpa

Tensile

Strength, Rm

MPa

Percentage

Elongation,

A

min.

%

KVb min. J Upper Yield

Strength,

Re

min.

Tensile

Strength,

Rm

MPa

Percentage

Elongation,

A

min.

%

KVb min. J

38Cr2 450 700 to 850 15 35 350 600 to 750 17 35

46Cr2 550 800 to 950 14 35 400 650 to 800 5 35

34Cr4 34CrS4 590 800 to 950 14 40 460 700 to 850 15 40

37Cr4 37CrS4 630 850 to 1000 13 35 510 750 to 900 14 35

41Cr4 41CrS4 660 900 to 1100 12 35 560 800 to 950 14 35

25CrMo4

25CrMoS4 600 800 to 950 14 50 450 700 to 850 15 50

34CrMo4

34CrMoS4 650 900 to 1100 12 40 550 800 to 950 14 45

42CrMo4

42CrMoS4750 1000 to 1200 11 35 650 900 to 1100 12

35

50CrMo4 780 1000 to 1200 10 30 700 900 to 1100 12 30

34CrNiMo6 900 1100 to 1300 10 45 800 1000 to 1200 11 45

30CrNiMo8 1050 1250 to 1450 9 30 900 1000 to 1300 10 35

35NiCr6 740 880 to 1080 14 35 640 780 to 980 15 35

36NiCrMo16 1050 1250 to 1450 9 30 900 1100 to 1300 10 35

36NiCrMo3 735 930 to 1130 11 35 685 880 to 1080 12 40

30NiCrMo16-6 880 1080 to 1230 10 35 880 1080 to 1230 10 35

51CrV4 800 1000 to 1200 10 30 700 900 to 1100 12 30

20 MnB5 600 750 to 900 15 60

30MnB5 650 800 to 950 13 60

38MnB5 700 850 to 1050 12 60

27MnCrB5-2 750 900 to 1150 14 60 700 800 to 1100 15 65

33MnCrB5-2 800 950 to 1200 13 50 750 900 to 1100 13 50

39MnCrB6-2 850 1050 to 1250 12 40 800 1050 to 1250 12 40

Re : Upper yield strength or, if no yield phenomenon occurs, the 0.2 % proof strength

Rm : Tensile Strngth

A : Percentage elongation after fracture

1 MPa = 1 N/mm2

KV: Impact strength of longitudional charpy-V-Notch test pieces (average of 3 individual values shall meet the minimum

specified in the table; no individual value shall be lover than 70% of the minimum shown in the table.

Steel

Designation

As per EN 10083 -3- Steels for quenching and tempering- Part 3 :

Table -8 Mechanical Properties at room temperature in the quenched and tempered condition

Mechanical Properties for the ruling section (See EN 10083-1) with diameter (d)

16 mm < d ≤ 40 mm 40 mm < d ≤ 100 mm

3.0 Self-drilling Anchors for Pipe roofs:

Self-drilling Anchors for pipe roofs is a pre support measure used in weak ground

condition in conventional as well as mechanized tunneling. Pipe umbrella pipes

increase the stability in the working area by transferring loads in the longitudinal

direction and decrease excavation induced deformation. The system increase

safety in the working area.

3.1 Uses: Roof and wall bolting as a temporary support in tunnels.


a) Drilling, grouting, and anchoring, in one operation. The hollow steel anchor

rod also acts as a grouting pipe to ease set up.


a) The ground is a vital element of the ground anchor system; therefore a

good quality geotechnical investigation is essential. Various parameters to

be considered during geotechnical investigations should include

Classification of rocks (Geometry of discontinuities, unit weight, degree of

weathering, Index test), Rock stratification, Unconfined compression

strength of intact rock, Shear strength and deformability of rock mass,

Permeability, Ground water conditions, Corrosion potentials of rock and

ground water etc.




proving tests should be undertaken to demonstrate the suitability of such

an arrangement. The design of the anchor should consider the following-

i. Loads and constraints of loading imposed by the anchors on the

overall structure



iii. The load distribution of the anchor arrangement on the structure

during stressing and during the design life of the structure

iv. The interface between the anchor and the structure to ensure

structural stability




diameter of rock bolts depend on the mass of the rock to be supported by

each rock bolt and the force of resisting shear in the bedrock.

d) EN 1997-1 – Geotechnical Design-Part 1: General Rules and BS EN 1537-

2013- Execution of Special Geotechnical work- Ground Anchors may be

followed for all geotechnical designs, installation of Ground Anchors. DIN

1054:2005-01 – Ground verification of the Safety of Earthworks and

Foundations is also being used for geotechnical designs for ground anchors.

e) Generally, Self-drilling Anchors for pipe roofs having minimum diameter 76

mm with a minimum yield load of 1200 kN are used as a temporary support

in tunnels. These are the lower limit of specifications & may vary as per

actual site conditions and design requirements; mechanical

properties/requirement accordingly can be adopted from the relevant codes

(EN-10083-1) (Annexure-III).

f) The yield loads of the bolt get transferred through thread to nut, washer,


accordingly. The rolled thread should be in accordance with ISO 10208.

g) Manufacturing of Self-drilling Anchors for pipe roof should conform to BS

EN-10083-1 “Steels for quenching and tempering - Part 1: General technical

delivery conditions”.

h) For all types of Self-drilling Anchors for pipe roof, the anchor head shall be

designed in accordance to BS EN 1537-2013, and should be able to

accommodate deformations, which may occur during the design life of the

structure.

i) Corrosion protection of Self-drilling Anchors for pipe roof should comply

with Para 6.9 of BS EN 1537-2013.

j) Tensile test of Self-drilling Anchors for pipe roof should be done in

accordance to BS EN ISO 6892-1: 2016. The test involves straining a test

piece in tension, generally to fracture, for the purpose of determining one

or more of the mechanical properties i.e. percentage elongation, tensile

strength, yield strength, upper yield strength etc.

k) Impact test of Self-drilling Anchors for pipe roof should be done in

accordance to BS EN ISO 148-1: 2016. The test consists of breaking by one

blow from a swinging pendulum, under conditions defined in code above.

The energy absorbed is a measure of the impact strength of the material.

l) Pull out test on Self-drilling Anchors for pipe roof should be performed of on

the basis of IS: 11309 – Method for conducting Pull-Out Test on Anchor

Bars and Rock Bolts.

- Minimum three pull out tests shall be conducted in one rock formation

as mentioned in clause 4.8 of IS: 11309 or as per the instructions of

Engineer-in-charge.

Annexure-III

Upper Yield

Strength,

Re

min.

Mpa

Tensile

Strength, Rm

MPa

Percentage

Elongation,

A

min.

%

KVb min. J Upper Yield

Strength,

Re

min.

Tensile

Strength,

Rm

MPa

Percentage

Elongation,

A

min.

%

KVb min. J

38Cr2 450 700 to 850 15 35 350 600 to 750 17 35

46Cr2 550 800 to 950 14 35 400 650 to 800 5 35

34Cr4 34CrS4 590 800 to 950 14 40 460 700 to 850 15 40

37Cr4 37CrS4 630 850 to 1000 13 35 510 750 to 900 14 35

41Cr4 41CrS4 660 900 to 1100 12 35 560 800 to 950 14 35

25CrMo4

25CrMoS4 600 800 to 950 14 50 450 700 to 850 15 50

34CrMo4

34CrMoS4 650 900 to 1100 12 40 550 800 to 950 14 45

42CrMo4

42CrMoS4750 1000 to 1200 11 35 650 900 to 1100 12

35

50CrMo4 780 1000 to 1200 10 30 700 900 to 1100 12 30

34CrNiMo6 900 1100 to 1300 10 45 800 1000 to 1200 11 45

30CrNiMo8 1050 1250 to 1450 9 30 900 1000 to 1300 10 35

35NiCr6 740 880 to 1080 14 35 640 780 to 980 15 35

36NiCrMo16 1050 1250 to 1450 9 30 900 1100 to 1300 10 35

36NiCrMo3 735 930 to 1130 11 35 685 880 to 1080 12 40

30NiCrMo16-6 880 1080 to 1230 10 35 880 1080 to 1230 10 35

51CrV4 800 1000 to 1200 10 30 700 900 to 1100 12 30

20 MnB5 600 750 to 900 15 60

30MnB5 650 800 to 950 13 60

38MnB5 700 850 to 1050 12 60

27MnCrB5-2 750 900 to 1150 14 60 700 800 to 1100 15 65

33MnCrB5-2 800 950 to 1200 13 50 750 900 to 1100 13 50

39MnCrB6-2 850 1050 to 1250 12 40 800 1050 to 1250 12 40

Re : Upper yield strength or, if no yield phenomenon occurs, the 0.2 % proof strength

Rm : Tensile Strngth

A : Percentage elongation after fracture

1 MPa = 1 N/mm2

KV: Impact strength of longitudional charpy-V-Notch test pieces (average of 3 individual values shall meet the minimum

specified in the table; no individual value shall be lover than 70% of the minimum shown in the table.

Steel

Designation

As per EN 10083 -3- Steels for quenching and tempering- Part 3 :

Table -8 Mechanical Properties at room temperature in the quenched and tempered condition

Mechanical Properties for the ruling section (See EN 10083-1) with diameter (d)

16 mm < d ≤ 40 mm 40 mm < d ≤ 100 mm

4. Water Expandable Rock Bolts:

The Water Expandable rock bolting system consists of specific rock bolts made

from steel tubes that have been folded onto themselves, with bolting accessories

and high pressure, installation pumps.

Water Expandable rock bolts are placed in drilled holes and expanded using

water from the installation pump. The high pressure water causes the bolts to

expand, filling the drill hole, consolidating any loose material remaining after

drilling and conforms to the irregularities of the hole. A combination of friction and

mechanical interlock is generated throughout the entire bolt length.

Water Expandable rock bolts interact directly with the rock without the need

for such auxiliaries as grouting agents or locking devices. Simply monitoring water

pressure provides quality control during installation. It gives immediate full load

bearing capacity over the entire installed bolt length with low sensitivity against

vibrations caused by blasting works. These rock bolts are safe and easy to install &

with no grouting required, this helps to avoid contamination also.

4.1 Use:

Water Expandable rock bolting system has gained wide recognition in mining and

tunneling works. Water Expandable rock bolt is a family of ground support system

that covers such demanding applications as high loading, deep support, large rock

deformations and corrosive environments.


a) Drill the hole.

b) Water Expandable rock bolt is placed.

c) Water injected under pressure forms the tube to the irregularities of the bore

hole, generating friction and mechanical interlocking.

d) The internal pressure is released leaving a permanently deformed tube that is

locked in place providing a strong interaction with the rock mass.


a) The ground is a vital element of the ground anchor system; therefore a good

quality geotechnical investigation is essential. Various parameters to be

considered during geotechnical investigations should include Classification of

rocks (Geometry of discontinuities, unit weight, degree of weathering, Index

test), Rock stratification, Unconfined compression strength of intact rock, Shear

strength and deformability of rock mass, Permeability, Ground water

conditions, Corrosion potentials of rock and ground water etc.



locations, spacing’s or inclinations are proposed, appropriate studies or proving

tests should be undertaken to demonstrate the suitability of such an

arrangement. The design of the anchor should consider the following-

i. Loads and constraints of loading imposed by the anchors on the overall

structure



iii. The load distribution of the anchor arrangement on the structure during

stressing and during the design life of the structure

iv. The interface between the anchor and the structure to ensure structural

stability




diameter of rock bolts depend on the mass of the rock to be supported by each

rock bolt and the force of resisting shear in the bedrock.

d) EN 1997-1 – Geotechnical Design-Part 1: General Rules and BS EN 1537-2013-

Execution of Special Geotechnical work- Ground Anchors may be followed for

all geotechnical designs, installation of Ground Anchors.

e) Generally, Water Expandable rock bolts with a minimum yield load of 150 kN

are used as temporary support in a tunnel. Rock bolt of higher strength may be

used as per actual geological site condition and design requirements.

f) Minimum external diameter of Omega (Ω) profile & external diameter for

expanded profile should be 36 mm and 54 mm respectively having minimum

wall thickness 2 mm. Borehole diameter should be between 43-52 mm for the

external diameter as recommended above.

g) These are the lower limit of specifications & may vary as per actual site

conditions and design requirements; mechanical properties/requirement

accordingly can be adopted from the relevant codes (BS EN-10149 Part-1).

h) Manual as well as automated installation is done by expansion of the omega

(Ω) shaped profile with high-pressure water of 300 bar for external diameter of

bolts as recommended above.

i) For installation of Water Expandable rock bolts, equipment as recommended by

the manufacturer of the bolts shall be used.

j) Manufacturing of Water Expandable rock bolts should conform to BS EN 10149-

1 – Specifications for Hot-rolled flat products made of high yield strength steels

for cold forming. Table placed as Annexure IV shows various mechanical

properties of thermo-mechanically rolled steels.

k) Corrosion protection of Water Expandable rock bolts should comply with Para

6.9 of BS EN 1537-2013.

l) Tensile test of Water Expandable rock bolts is done in accordance to BS EN

10149-1 & BS EN ISO 6892-1: 2016. The test involves straining a test piece in

tension, generally to fracture, for the purpose of determining one or more of

the mechanical properties i.e. percentage elongation, tensile strength, yield

strength, upper yield strength etc.

m) Impact test of Water Expandable rock bolts should be done is done in

accordance to BS EN 10149-1. The test consists of breaking by one blow from

a swinging pendulum, under conditions defined in code above. The energy

absorbed is a measure of the impact strength of the material. The minimum

impact energy value will be 40 Joules.

n) The Bend test shall be carried out in accordance with BS EN ISO 7438: 2016.

o) Pull out test on Water Expandable rock bolts should be performed of on the

basis of IS: 11309 – Method for conducting Pull-Out Test on Anchor Bars and

Rock Bolts.


mentioned in clause 4.8 of IS: 11309- or as per the instructions of

Engineer-in-charge.

Annexure-IV

5. Glass-reinforced Plastic (GRP) Bolts:

GRP Bolts are fiber bolts made of glass fiber reinforced with strengthened plastic.

Glass-reinforced Plastic (GRP) Bolts are used for face bolting as temporary

support measure. It is used where bedrock is to be reinforced in advance so that

it may be easily cut by boring in later process.

5.1 Uses:

Face-bolting and temporary applications: Cut-ability of GRP makes it the ideal

solutions for face bolting or any other tunneling/mining application where face

support is required for further excavation.

5.2 Specifications:

a) GRP Bolts are used for face bolting of the tunnel to reinforce it in advance as

per actual geological site condition and requirements.

b) It gives high flexibility which is well suited for application without couplings

in confined locations.

c) Generally, GRP Bolts having minimum nominal diameter of 20 mm for

Solid/Hollow /Self- Drilling Bolts. The Minimum tensile strength should be

850 N/mm2. The minimum torsional strength of GRP bolts shall be 100 Nm

in both directions. These are the lower limit of specifications & may vary as

per actual site conditions and design requirements.

d) GRP Bolts should conform to BS 7861-1-Strata reinforcement support

system- specification for rock-bolting.

e) Tensile strength test is done in accordance with Annexures - H of BS 7861-1.

It is determined by subjecting the test sample to a tensile force until failure

occurs.

f) Flexural Strength test is done in accordance with Annexure - J of BS 7861-1;

it is determined by subjecting a test specimen to a three point bend test.

The material shall have a flexural strength of not less than 750 N/mm2.

g) Torsional strength test is done in accordance with Annexure-G of BS-7861-1;

it is determined by subjecting the test sample to a torsional force in both

directions until failure occurs.

6. Cement Grout for Rock Bolting

Rockbolts have been used for many years for the support of underground

excavations. Rock bolts are used as the main support for structures such as

tunnels and mines where safety is critical. For proper anchorage/bonding between

Bolt and surrounding Rock mass, all bolt holes must be grouted completely with

cement grout.

6.1 Functions of Grouting:

a) To form the fixed anchor length in order that the applied load may be

transferred from the bolts to the surrounding ground.

b) To protect the bolt against corrosion.

c) To strengthen the ground immediately adjacent to the fixed anchor in order to

enhance the ground anchor capacity.

d) To seal the ground immediately adjacent to the fixed anchor length in order to

limit the loss of grout.

Note: If a grout volume injected is in excess of three times the borehole

volume at pressures not exceeding total overburden pressure, then general

void filling is indicated which is beyond routine anchor construction. In such

cases pre-grouting void filling may be necessary before grouting the anchor.

Placement of grout should be carried out as soon as possible after completion

of drilling.

6.2 Generalized specifications of cement grout are as under:

a) The cement grout shall be mechanically mixed to produce a uniform

consistency.

b) The selection of the type of cement for the grout should consider the

aggressiveness of the environment, the permeability of the ground and the

design life of the bolts.

c) The aggressiveness of environment may be determined in accordance with

EN 206-1 & taken into consideration as required.

d) Ordinary Portland cement shall be used. (BIS 269: 2015). It shall be

compatible with the reinforcing elements.

e) The cement grout shall conform to EN 14490.

f) Water /cement ratios (weight-ratio) should be appropriate to the ground

conditions, anchorage system construction method, durability and strength

requirements. Maximum water cement ratio to be limited to 0.55 to ensure

barrier against corrosion and other aggressive agents and stress.

g) Typically, grout should achieve a minimum characteristic strength of 5 Mpa

prior to load being induced in the grouted anchor, and the 28 days

characteristic strength of the grout mix should not be less than 25 MPa.

h) Thixotropic consistency to make grouts suitable for vertical holes.

i) It should have enough workability for easy pumping and placement.

j) The bolt/ dowel shall be protected against disturbance for a minimum time of

48 hours after installation or more as required by Engineer-in-charge.

k) After the grout has gained adequate strength, washer plates shall tighten

against the rock face, so as to induce positive compression in rock mass

around the bolts.

l) Inert fillers may be incorporated within the grout, for example the

introduction of sand. Sand for grouting purpose shall be clean mineral sand,

uniform in quality and from an approved source. Water shall be clean, free

from oil, acid, alkaline, organic and other deleterious substances. This

material shall be approved by the Engineer.

m) Admixtures may be used for improving workability, durability, reducing bleed,

reducing shrinkage or adjusting rate of setting and strength development.

n) Admixtures should not contain any product liable to damage the reinforcing

element or the grout itself. Admixtures that contain more than 0.1% by mass

chlorides, sulphates or nitrates should not be used.

7. Waterproofing system

Waterproofing system for watertight (dry) tunnel may consist of two layers; the

first shall consist of protective felt fastened to the shotcrete surface: the second

layer shall be the actual waterproofing membrane properly fixed by special mean

as recommended by manufacturer.

7.1 Waterproofing Membrane

The purpose of waterproofing membrane for underground structures is to prevent

leakage of groundwater into the tunnel and to protect the final concrete lining

against deleterious chemical influences. Waterproofing shall be applied to crown

and sidewalls above footing or inverted arch level.

7.2 Specifications

a) As per IS-15909: PVC Geomembrane for Lining Specification.

b) The PVC geomembrane shall be suitably manufactured from vinyl chloride

resin homo polymer. Water soluble compounding ingredient shall not be used.

Plasticizers that are resistant to migration and bacterial growth shall be used.

c) The thickness of geomembrane generally for this application shall be 2mm

with allowable tolerance of ±7.5%. (para 3.2 of IS 3464)

d) In case two or more layers of PVC films are used. These shall be joint together

by a suitable heat fusion lamination only, having minimum peel strength of

1.05 kN/m.(para 12 of IS 3464)

e) The PVC geomembrane shall be reasonably free from defects such as holes,

tear or blisters.

f) Specific gravity should be ranging from 1.3 to 1.4.(Appendix A (Method A)of

IS 2076)

g) It shall have tensile strength of ≥160 kg/cm2, and elongation at break of ≥

250%.(Appendix B of IS 2076)

h) The tear strength of membrane should be minimum of 110 N in machine

direction & 80 N in cross direction, determined in according with the method

described in (Annexure A of IS 15909).

i) It shall have Index puncture resistance of ≥ 525 N.(Annexure B of IS 15909)

j) For low temperature crack resistance, geomembrane shall not crack when

bend 1800 by hand over the mandrel at a temperature of -30±20C. (Annexure

C of IS 15909)

k) It shall have hydrostatic resistance of ≥25 kg/cm2.(Annexure D of IS 15909-

Test specimen is clamped in between two circular clamps of about 76mm dia.

The pressure is generated by means of piston forcing water into the pressure

chamber of the apparatus at rate of 1.4±0.1 cm3/s until the specimen fails.)

l) It shall have Seam strength of ≥75 % of original value. (Annexure E of IS

15909- Specimen is placed in the jaws of the tensile testing machine with the

seam centered between and parallel to the jaws and width of the specimen at

right angles to the direction of application of force. Record the necessary load

to slip the seam or rupture the specimen is recorded to get the seam strength)

m) The maximum volatile matter in the geomembrane shall be limited to 1%. The

loss of mass of PVC membrane shall be express as volatile loss when it place

in oven at temperature 100± 20C for 6 hours.(para 7 of IS 3464)

n) Maximum change in Tensile strength and Elongation at break after buried in

soil shall be 5% and 20% respectively. (Annexure F of IS 15909 – Test

specimen is buried in soil that is rich in cellulose destroying microorganism to

the depth of about 200 to 500 mm. After 30 days determine the tensile

strength and elongation at break.)

o) Reduction in weight of geomembrane after being immersed completely in

distilled water for 24 hours at room temperature should not be greater than

0.15%.(Annexure G of IS 15909)

p) Stability to UV radiations, percent retention in tensile strength and elongation

at break of shall be ≥80%, when expose to ultraviolet radiation in a Xenon-arc

apparatus for 500 hrs. (Annexure H of IS 15909)

7.2.1 Draft recommended specifications of PVC waterproofing membrane

S.N Property Requirement

Standard

1. Length and width

As agreed (Tolerance ± 1%)

Para 3.4 of IS 3464

2. Thickness (mm)

2 (Tolerance ± 7.5%)

Para 3.2 of IS 3464

3. Specific gravity 1.3 - 1.4

Appendix A (Method A)of IS 2076

4. Tensile strength (kg/cm2) ≥160

Appendix B of IS 2076

5. Elongation at break ≥ 250%

Appendix B of IS 2076

6. Tear strength, N a) Machine direction b) Cross direction

≥110 ≥80

Annexure A of IS 15909

7. Index Puncture Resistance, N ≥525

Annexure B of IS 15909

8. Low temperature crack resistance

Shall not break ,crack at -30± 20C

Annexure C of IS 15909

9. Hydrostatic resistance, kg/cm2 ≥25

Annexure D of IS 15909

10. Seam strength, kg

≥75% of original value

Annexure E of IS 15909

11. Volatile loss ≤1% Para 7 of IS 3464

12. Peel strength, KN/m ≥1.05 Para 12 of IS 3464

13. Resistance to soil burial a) Tensile strength percentage

change b) Elongation at break

percentage change

≤5 ≤20

Annexure F of IS 15909

14. Water extraction, percentage loss in weight

≤0.15 Annexure G of IS 15909

15. Stability to ultraviolet radiations, percentage in tensile strength and elongation at break.

≥80 Annexure H of IS 15909

8. Non-Woven Poly-Propylene Geo-Textile

It is a layer of protective felt fastened to the shotcrete surface which is a

continuous filament non-woven poly-propylene geotextile of uniform thickness and

surface texture, which shall meet the draft specification as listed below.

8.1 Use

The typical use will be as a protective covering or underlayment of a

geomembrane against puncture or tear due to rock, stones, concrete or other hard

surface and/or objects.

8.2 Specifications:

a) For these applications, Geo-Textile shall have minimum unit weight of 500g/m2.

(Testing as per ASTM D-5261).

b) It shall have a minimum tensile strength of 1.64 kN with extension at break of

70% (minimum). (ASTM D 4632- A Continually increasing load is applied

longitudinally to the specimen and the test is carried to rupture. Values for the

breaking load and elongation of the test specimen are obtained.)

c) Minimum Trapezoidal Tear Strength of the geotextile should be 0.64 kN.

(Testing as per ASTM D-4533).

d) Maximum 10% loss of strength is allowable for the Geo-Textile, when tested

for resistance against acid and alkaline solution pH 2-13. (EN : 14030-

Specimen completely immersed in a test liquid for 3 days at a temperature of

60 ± 10 C. Properties of the test specimen are tested before and after

immersion).

e) Resistance to punching should be a minimum of 4000 N. (ASTM D-6241- A test

specimen is clamped without tension between circular plates and secured in a

tensile testing machine. A force is exerted against the centre of the

unsupported portion of the test specimen by a steel plunger attached to the

load indicator until rupture occurs. The maximum force is the value of puncture

strength).

f) Stability to UV radiations; Percent retention in tensile strength and elongation

at break shall be ≥70%, when expose to ultraviolet radiations in a Xenon-arc

apparatus for 500 hrs. (ASTM D-4355)

8.2.1 Draft Recommended Specification of Non-woven poly-propylene Geo

textile (Protective layer)

Properties

Specified Value Standard

Unit weight

500 g/m2 minimum ASTM D-5261 or Equivalent EN

Tensile Strength

≥1.64 kN ASTM D-4632 or Equivalent EN

Extension at break

≥50 % ASTM D-4632 or Equivalent EN

Trap. Tear strength

≥0.64 kN ASTM D-4533 or Equivalent EN

Resistance to Punching

≥4000 N ASTM D-6241 or Equivalent EN

Resistance against acid and alkaline solution pH 2-13

Loss of strength 10% max

EN : 14030 or Equivalent ASTM

UV Resistance @ 500 hrs

≥70% ASTM D-4355 or Equivalent EN

Note: All values are Minimum Average Roll Value (MARV) except UV resistance, which

is derived statistically as average value minus two standard deviations.

Reference:- GRI ; GT12(a) for “ Test Methods and Properties for Nonwoven Geotextiles

Used as Protection (or Cushioning) Material”

9. Polyurethane Grout

9.1 Definition:

Polyurethane Grout comes under Chemical grout which has sufficient fluidity to be

injected or pumped in to a porous body or into crack that reacts in place to form a

gel, foam or solid.

9.2 Uses & Purpose:

Polyurethane grouting is considered to be the most common defense towards

water ingress in tunnel. It is a technique that involves the injection of expanding

polyurethane to cutoff water flow through joints or cracks or to fill voids beneath

or behind subsurface of excavated area.

It can be single or multi component grout and can react when coming in contact

with water or require a reactant. The grout is injected with pressure through a

predrilled hole, grout then expands to fill the crack or void.

Many polyurethane grout products are available with variation in viscosity, reaction

time, reaction with water, expansion characteristics and flexibility of reacted grout.

It is important to select proper grout for specific site conditions based on techno-

economic consideration. Polyurethane grout is being used as remedial measures to

divert the water seepage and may assist in rock mass stabilization. It is also to be

noted that PU grouting is not an alternate to rock bolting for rock mass

stabilisation.

Before grouting a rock mass, there are a number of important considerations

that will help maximize the efficiency and effectiveness of grouting.

a) Rock mass characterization is important. From the characterization of the rock

mass, one can estimate the void space within the target zone, which is

extremely important when applying Polyurethane grouting.

b) By estimation of void space one can estimated the amount of Polyurethane

needed to be pumped into the rock for stabilization.

c) It is very important to perform an accurate and thorough investigation of the

rock mass, because these considerations will subsequently drive the design

decisions for the project, including the selection of the most appropriate

Polyurethane product.

d) The Polyurethane products should be injected at an air/structure temperature

between 130 and 320 C, if product is installed above or below this temperature

the resin viscosity and set time will be affected.

e) PU and PUR product may be used after observing the number of mixing

components, reactivity with water, and application setting etc.

9.3 PU Grout

a) Polyurethane (PU) is extremely versatile plastics in terms of forms in which

they are available: flexible or rigid foams, solid elastomers, coatings, adhesives

and sealants.

b) Polyurethane (PU) generally only requires a single stage mix component with

an accelerator added to set the reaction time. Set time can vary widely,

ranging from 15 seconds to several hours.

c) Single stage PU products, using foam or gels, are commonly used for crack

repair, void filling, consolidation of weak strata and ground water contaminant

flow barrier.

d) They form foam extensively in presence of water. PU single stage grouts are

generally lower in strength and are considered more as water sealant

(especially for hydrophilic type grout) than a stabilization purpose.

9.3.1 Draft Specification:

Property Polyurethane (PU)

Components Mixing One Stage

Injection Type Foam/Gels/Grout

Injection Pressures Low to High (100-3000 psi) (0.7-20.7 MPa)

Density

Low to Medium

3- 50 pcf (0.05-0.8 g/cm3), Testing as per ASTM

D 4659

Compressive/Tensile Strength

Low

10 – 500 psi (0.07-3.44 MPa)

Tensile Strength testing as per ASTM D 638.

Compressive Strength as per ASTM D 695

Viscosity Low to Medium

Water Interaction Hydrophilic

Expansion/Elongation Varies 10 – 3000 %

Shrinkage Varies 1 – 10 %

9.4 PUR Grout

a) Polyurethane resins (PUR) most commonly fall within the category of a two

stage mix component system. In general PUR considered a higher strength

injection grout used for rock stabilization.

b) The set time can vary from seconds to hours depending on application and

temperature.

c) Two stage mix system products have greater compressive and tensile strengths

than single stage mix system.

d) Fractured incompetent rock strata are injected under pressure with two

components at a ratio 1:1 for stabilization, forming an elastomer known as

glue. This provides supplementary support of weak areas and structures.

e) PUR grouts are being used to stabilize rock mass as well as to divert the

excessive water seepage.

9.4.1 Draft Specification:

Property Polyurethane Resin (PUR)

Components Mixing Two Stage

Injection Type Grout

Injection Pressures Low to High (10-3000 psi) (0.07-20.7 MPa)

Density Medium to High 20 - 70 pcf (0.32-1.12 g/cm3)

Testing as per ASTM D 4659

Compressive/Tensile

Strength

Low to High 15 – 20000 psi (0.01-138 Mpa)

Tensile Strength testing as per ASTM D 638.

Compressive Strength testing as per ASTM D 695

Viscosity Low to High

Water Interaction Hydrophilic/Hydrophobic

Expansion/Elongation Varies 10 – 3000 %

Shrinkage Varies 0 – 3 %

a) It should be noted that the properties given in above tables provide relative

comparison of products; there are always exceptions, and products can be

manufactured with different component mixes to address a broad range of

applications.

b) Many polyurethane grout products are available with variation in viscosity,

reaction time, reaction with water, expansion characteristics and flexibility of

reacted grout. It is important to select proper grout for specific site conditions

based on techno-economic consideration.

c) Application of PU & PUR grout are site specific and hence properties will vary

accordingly and while selecting the proper product and carrying out work on

site, expertise in this field is required.

Ref: 1.Polyurethane Resin (PUR) injection for rock mass stabilization

Publication No. FHWA-CFL/TD-08-004/September-2008

2.Performance of Polyurethane grouting to handle heavy seepage in tunnels,

By N Rana and R Nair, L& T Construction, Chennai

3. Polyurethane grouting technologies, By Jan Bodi, Zoltan Bodi,Jiri Scucka

and Petr Martinec

GEO-TECHNICAL ENGINEERING DIRECTORATE

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