BOX PUSHING
TECHNIQUE:
PROBLEMS AND
REMEDIAL
MEASURES
1
Under auspicious guidance of
Shri. S.K.Garg SPW/IRICEN/Pune
Special thanks to
Shri. V.B.Sood PB/IRICEN/Pune
ByB.Tripathi
K.K.Choudhary
V.K.Khare
( C.N.- 9101 Integreted )
2
1
Alternatives of constructing
opening in railway track
• BY CONVENTIONAL METHOD
(By providing Service Spans/R.H. Girders)
• BY PUSH THROUGH METHOD
3
Advantages of Box
push through technique
•
•
•
•
•
•
No disruption to rail traffic.
Better quality control.
Economical
Time of completion is less.
Saving in man power & Machinery.
No involvement of crane & heavy
equipment.
• Less involvement of other Departments.
4
2
Disadvantages of Box Pushing
method
1. Needs trained staff and skilled
supervision.
2. Imposition of caution order exist for
a longer period .
3. No scope of night working.
4. Once the vertical & lateral alignment
of box disturbed it becomes almost
impossible to rectify it.
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Collection of site data
• 1. Topography of area.
• 2. Detail cross section considering
• Rail level
• Formation level
• Width of embankment
• Ground level
• 3. Route of signaling cables, electric &
telecom cables.
• 4. Nearest river or Nallah course.
• 5. Trail pit bore details.
• On embankment
• On ground level
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3
Stages in execution of work
1. Excavation for thrust bed and auxiliary
bed.
2. Concreting of thrust bed & pin pockets.
3. Casting of box segments.
4. Protection of track & embankment.
5. Arrangement of adequate capacity jacks
with power pack.
6. Pushing operation.
7. Construction of Wing wall/Toe wall/Return
wall.
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•Arrangement of jacks
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4
Some problems encountered
during box pushing
1.
2.
3.
4.
5.
6.
7.
8.
9.
Tilting of box .
Shifting of longitudinal alignment.
Failure of pin pocket.
Leaking of joints.
Occurrence of boulder layer.
Occurrence of hard rock.
Occurrence of collapsible strata.
Unexpected floods during box pushing.
9
Disturbance in track geometry.
Tilting of Box
• Effects
– Lifting of track adversely.
– Differential earth cushion above box.
– Creation of gap between two segments.
– Excessive resistance in pushing
subsequent segment.
– Reduction in space for ballast wall
construction.
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5
Tilting of Box
• Remedies
– Proper fixing of metal sheet at rear end
of segments.
– Obstruction against cutting edge to be
removed during pushing.
– Preferably pushing should be 300mm at
a time.
– Fix the reference points to check the
vertical and lateral alignment regularly.
– Differential jacking to rectify tilt.
11
Method to check the settlement of formation
Plan
Isometric view
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6
Measure to control the lowering & lifting
Plan
Elevation
13
• Habibganj-Bhopal @ Km. 833/5-6
• Tilted box
14
7
• Habibganj-Bhopal @ Km. 833/5-6
• Tilted box
15
Shifting of longitudinal alignment.
• Effects
– Pressure on jacks of one side will increases
abruptly may cause failure of jacks.
– There will be a gap creation at the junction
of two boxes.
– Road becomes skew may lead to damages
through hitting of box by vehicles .
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8
Shifting of longitudinal alignment.
• Remedial Measures
– Reference pegs to be fixed with respect to
the centre line of box.
– Regular checking the longitudinal
alignment.
– Differential jacking to rectify longitudinal
alignment.
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Checking the longitudinal alignment
Plan
Isometric view
18
9
Failure of
pin pockets
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Precautions
• Entire concrete to be casted in one go.
• Concrete shall be dense & properly compacted.
• M.S. sheet of adequate thickness to be provided
in pockets
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10
Leakage
from joints
21
Precautions
• M.S. plate to be provided at top of the junction of
two boxes .
• Epoxy grouting to be done from inside.
M.S. plate
22
11
M.S. plate
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Occurrence of boulder layer
• Effects
– Obstruction to cutting edge.
– Hindrance in pushing hence more time
consumption.
– Excessive pressure affects efficiency
of jacks.
– Ballast get through voids between
boulders and drop down results
hanging position of sleepers in unsafe
condition.
– Disturbance in track geometry.
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12
Occurrence of boulder layer
• Remedial measures
– Excess ballast unloading at site.
– Removal of boulders manually to be tackled
in small segments of entire width.
– Boulder removed segments to beprotected
by providing gunny bags filled with sand
simultaneously.
– Preferably pushing carried out under traffic
block.
– Stablizing of sub grade by using Betonite
power.
25
• BINA – KATNI Section @ Km. 1020.720
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13
• BINA – KATNI Section @ Km. 1020.720
27
• BINA – KATNI Section @ Km. 1020.720
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14
• BINA – KATNI Section @ Km. 1020.720
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• BINA – KATNI Section @ Km. 1020.720
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15
• BINA – KATNI Section @ Km. 1020.720
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Occurrence of Hard rock
• Effects
–
–
–
–
Tilting of box / deviation in alignment.
Manual excavation becomes ineffective.
Bending of cutting edge.
Failure of jacks due to excessive
pressure.
– Slow process affects the entire progress.
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16
Occurrence of Hard rock
• Remedial measures
– Mechanical arrangement like
compressors, pavement breaker ,
splitters etc. is required.
– Controlled blasting may be resorted to.
– Cutting edge should be designed as per
site conditions.
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Pachora – Jalgaon section @ 383/22-24
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17
Occurrence of collapsible strata
• Effects
– Sudden collapse of sub grade.
– Settlement of the track.
– Safety hazards during passage
of traffic.
– Cautious & slow process.
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Occurrence of collapsible strata
• Remedial measures
– Stabilization of sub grade with Betonite.
– Frequent recoupment of Ballast & track
attention.
– Small length to be attempted during
pushing.
– Arrangement of CC cribs and girders at site
to deal emergencies.
– Sufficient numbers of gunny bags filled
with sand kept ready.
– In case of collapsed bank RH girders to be
provided .
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18
• JALGAON – BHUSAWAL @ Km. 428/8-10
37
• JALGAON – BHUSAWAL @ Km. 428/8-10
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19
• JALGAON – BHUSAWAL @ Km. 428/8-10
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• JALGAON – BHUSAWAL @ Km. 428/8-10
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20
Unexpected flood during box pushing
• Effects
– Damage to the slope of the banks.
– Submergence of machinery interrupt
the process.
– Disturbance to cess require
protections.
– Excessive friction due to wet soil
mass.
– Collapse of bank due to water current
& heavy rain.
41
Unexpected flood during box pushing
• Remedial measures
– Unloading of Boulder / quarry dust
rake for bank protection.
– Sufficient numbers of gunny bags
filled with sand kept ready.
– Shoring arrangements to be made
available.
– Revision of caution orders as per site
conditions.
– Water pumping arrangements along
with provision of coffer dams.
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21
Unexpected flood
• BINA – KATNI Section @ Km. 1020.720
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Disturbance due to unexpected flood
• BINA – KATNI Section @ Km. 1020.720
44
22
Disturbance due to unexpected flood
• BINA – KATNI Section @ Km. 1020.720
45
Disturbance due to unexpected flood
• BINA – KATNI Section @ Km. 1020.720
46
23
Disturbance due to unexpected flood
• BINA – KATNI Section @ Km. 1020.720
47
Disturbance due to unexpected flood
• BINA – KATNI Section @ Km. 1020.720
48
24
Disturbance due to unexpected flood
• BINA – KATNI Section @ Km. 1020.720
49
Disturbance due to unexpected flood
• BINA – KATNI Section @ Km. 1020.720
50
25
Disturbance due to unexpected flood
• BINA – KATNI Section @ Km. 1020.720
51
Shoring arrangements
• BINA – KATNI Section @ Km. 1020.720
52
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Shoring arrangements
• BINA – KATNI Section @ Km. 1020.720
53
Shoring arrangements
• BINA – KATNI Section @ Km. 1020.720
54
27
Shoring arrangements
• BINA – KATNI Section @ Km. 1020.720
55
Shoring arrangements
• BINA – KATNI Section @ Km. 1020.720
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28
Disturbance of track geometry
• Effects
– Abrupt cross level variation.
– Resulting in deficiency of ballast
requires frequent recoupment.
– Bulging of side slopes.
– Shifting of earth mass along with
box.
– Lateral shifting of the alignment.
57
• BINA – KATNI Section @ Km. 1020.720
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29
Disturbance of track geometry
• Remedial measures
– Arrangement of Tirfors to resist the
movement of track along with box.
– Epoxy painting on top surface/use of
drag sheet to reduce friction.
– Recording of track parameters & frequent
attentions.
– Unloading of sufficient ballast well in
advance.
– Deployment of sufficient labour to correct
the disturbed track structure.
– Daily pushing without interruption to
avoid frictional resistance .
– Counter weight on the exit end of bank.
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• Epoxy painting
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30
• Drag sheet arrangement for smooth pushing
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• Drag sheet arrangement for smooth pushing
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31
• Drag sheet arrangement for smooth pushing
63
• Counter weight
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Conclusions and Suggestions
• Box pushing work means at least partly
working in blind , so problems usually
come up during execution of work.
• Box pushing work require close
supervision and monitoring and quite
often the unsafe conditions develop at
these sites.
• Track must be watched regularly to see
signs of heaving, settlement,
misalignment etc.
• LWR must be cut and site isolated during
box pushing.
• Work must be done under block
protection / caution order only.
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