Behaviour of slab track under extreme stress conditions · EUROPEAN SLAB TRACK SYMPOSIUM 2005 [ ] 1 Behaviour of slab track under extreme stress conditions

. EUROPEAN SLAB TRACK SYMPOSIUM 2005 [ www.ifv-bahntechnik.de/euro-info ] 1

Behaviour of slab track under

extreme stress conditions

European

Slab Track

Symposium Bruxelles

22 February 2005

Behaviour of slab track

under extreme stress conditions

Dr.-Ing. Lutz VogtPD Dr.-Ing. Peter-Andreas von WolffersdorffDr.-Ing. Erich Rehfeld

phone: +49 (0) 351 824 13 50http://[email protected]

European Slab Track Symposium, Bruxelles, 22. February 2005 13:25 - 13:50




European

Slab Track

Symposium Bruxelles

22 February 2005

Proposed advantages of slab track

for high-speed railways

� Durability

� Low maintenance costs

� Economical selection of route elements




European

Slab Track

Symposium Bruxelles

22 February 2005

Slab track development in Germany

accompanied by BAUGRUND DRESDEN

� Slab track field test (e.g. Breddin-Glöwen, Waghäusel,

Eckartshausen)

� High-speed line from Hannover to Berlin

� High-speed line from Cologne to Frankfurt/Main

� High-speed line from Nuremberg to Ingolstadt




European

Slab Track

Symposium Bruxelles

22 February 2005

Influences on the load-bearing

behaviour of slab track

� Dynamic axle loads, depending on static axle loads, train velocity, vehicle and track component quality,

properties of the substructure

� Temperature effects

� Cyclic behaviour of slab and substructure

� Building process




European

Slab Track

Symposium Bruxelles

22 February 2005

Characteristics of the standard calculation

method for slab tracks in Germany

� Design leads to safe tracks and durable slab structure

under standard stress conditions

� Determination of behavioural reserves of slab track

under standard stress conditions is not possible

� Determination of the behaviour of slab track under

extreme stress conditions is not possible

� Simplified approach to the underground reaction, the

dynamical behaviour and the interaction between the

layers of the slab structure




European

Slab Track

Symposium Bruxelles

22 February 2005

Model aspects of the load-bearing


� Splitting temperature and axle loads

� Safety factors for loads (UIC) and material properties

� Simplified approach to the mechanical model concerning

interval and width of cracks

� Substructure model as ground reaction




European

Slab Track

Symposium Bruxelles

22 February 2005

� No failure but suggested reduction of serviceability and

shortening of life cycle

� Many influence factors and the time dependent

behaviour of slab track make general approaches very

difficult

� Work on special parts and calibrate the calculations with

test results, observations and measurements

Model aspects of the load-bearing





European

Slab Track

Symposium Bruxelles

22 February 2005

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Time depending settlement at so called white dam (high speed line from Colongne to Frankfurt/Main, km 121,841-122,070)

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prediction/fitting




European

Slab Track

Symposium Bruxelles

22 February 2005

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Settlement under the rail at so called white dam (high speed line from Colongne to Frankfurt/Main, km 121,841-122,070)




European

Slab Track

Symposium Bruxelles

22 February 2005

Dam with extreme settlement (high speed line from Colongne to Frankfurt/Main, km 72,602-72,692)




European

Slab Track

Symposium Bruxelles

22 February 2005

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Settlement till February 2004 (high speed line from Colongne to Frankfurt/Main, km 72,602-72,692)

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European

Slab Track

Symposium Bruxelles

22 February 2005

Slab track without visible defects (high speed line from Colongne to Frankfurt/Main, km 72,602-72,692)




European

Slab Track

Symposium Bruxelles

22 February 2005

area of settlement

maximum settlemen: 18 mm

northern rail

Settlements at high speed line from Hannover to Berlin, Dallgow




European

Slab Track

Symposium Bruxelles

22 February 2005

Cracks in the slab structure at high speed line from Hannover to Berlin, Dallgow

shallow crack

in the concrete slab

open cracks

Dg, 11




European

Slab Track

Symposium Bruxelles

22 February 2005

HGT

6 m

5 m

4 m

3 m

2 m

1 m

0 m

BTS

GW

gravel

compacted sand

[SE]

sand

SE

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SE

sand

SW-SI

clay

injection zone 1

injection zone 2

crack injection

Underground situation and restoration method at Dallgow




European

Slab Track

Symposium Bruxelles

22 February 2005 Dg, 11

Injection between the layers of the slab structure at high speed line from Hannover to Berlin, Dallgow




European

Slab Track

Symposium Bruxelles

22 February 2005

-20,0

-15,0

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-5,0

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northern rail

southern rail

settlement before restorationnorthern rail

southern rail

settlement after restoration

+ 90 m

area of restoration

0 mm

5 mm

10 mm

- 5 mm

- 10 mm

- 15 mm

- 20 mm

120,238 + 10 m + 20 m + 30 m + 40 m + 50 m + 60 m + 70 m + 80 m

Dg, 27

Restoration by injection at at high speed line from Hannover to Berlin, Dallgow




European

Slab Track

Symposium Bruxelles

22 February 2005

� Settlements caused by substructure compaction due to

predominant static load have only little effect on slab

structure and can be readjusted

� Settlements caused by dynamic overload of the

substructure lead to extreme stress conditions of the slab track and require underground as well as slab structure

restoration

� Slab track-underground-interaction is essential for the

stress conditions of the slab track and can be verified by

dynamic response of the underground

Experiences with extreme settlements

under slab track




European

Slab Track

Symposium Bruxelles

22 February 2005

� Accompanying field tests (underground investigation,

measurements, laboratory tests)

� Calculations using the Finite Element Method to investigate

the realistic behaviour of slab track

� Calibrate the calculations using measurement results

� Parameter studies for extreme conditions

Investigation of slab track behaviour




European

Slab Track

Symposium Bruxelles

22 February 2005

Field test with slab track in Eckartshausen




European

Slab Track

Symposium Bruxelles

22 February 2005

Results of the field test in Eckartshausen

� Very high dynamic loads (vibrating 2 axle loads each

200 kN) caused settlements up to 20 mm

� Slab track spanned over settlement hollow but did not

break

� Adhesion losses between concrete slab and hydraulic

bonded layer

� Fibre reinforced concrete increases elasticity and load

bearing capacity




European

Slab Track

Symposium Bruxelles

22 February 2005

Modelling slab track using the Finite Element Method




European

Slab Track

Symposium Bruxelles

22 February 2005

� Bending stresses in the hydraulic bonded layer are smaller

than the stresses derived from standard calculation method in

Germany

� Adhesion losses between concrete slab and hydraulic bonded

layer cause comparatively little stress increase because of friction preservation

� Calibration of the Finite Element Model using measured vertical deflection due to dynamic loads (0,1 – 0,4 mm) leads

to very rigid material behaviour

� Change of underground stiffness in longitudinal direction up to

10 times causes change of stresses up to 2 times

Analysis results




European

Slab Track

Symposium Bruxelles

22 February 2005

Outlook: Realistic prediction of settlements due to rail loads

Finite Element Model of the substructure using a constitutive law with intergranular strain (hypoplasticity)




European

Slab Track

Symposium Bruxelles

22 February 2005




European

Slab Track

Symposium Bruxelles

22 February 2005

Settlement after 10 load cycles

0 30 60 90 120-1,e-3

-8,e-4

-6,e-4

-4,e-4

-2,e-4

0,0

axle load [kN/m]

se

ttle

me

nt

[m]




European

Slab Track

Symposium Bruxelles

22 February 2005

Behaviour of slab track

under extreme stress conditions

Dr.-Ing. Lutz VogtPD Dr.-Ing. Peter-Andreas von WolffersdorffDr.-Ing. Erich Rehfeld

phone: +49 (0) 351 824 13 50http://[email protected]

European Slab Track Symposium, Bruxelles, 22. February 2005 13:25 - 13:50




European

Slab Track

Symposium Bruxelles

22 February 2005

Rail head deterioration after grinding




European

Slab Track

Symposium Bruxelles

22 February 2005

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Measurement of particle velocity for various train velocity

train velocity [km/h]

eff

ective

pa

rtic

le v

elo

city [

mm

/s]

measurement position: top of concrete slab

area with underground defects

before restoration

area with underground defects

after restoration

reference area

Behaviour of slab track under extreme stress conditions · EUROPEAN SLAB TRACK SYMPOSIUM 2005 [ ] 1 Behaviour of slab track under extreme stress conditions

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