TUNNELLING IS OUR BUSINESS - ZSoil · Numerics in geotechnics and structures 2010 ......
Transcript of TUNNELLING IS OUR BUSINESS - ZSoil · Numerics in geotechnics and structures 2010 ......
ArbeitsklausurWagrain, 15./16.04.2010
TUNNELLING IS OUR BUSINESS
Modelling aging shotcrete:parameter identification and application
Matthias Hofmann
Numerics in geotechnics and structures 2010
ALPINE BeMo Tunnelling
ArbeitsklausurWagrain, 15./16.04.2010
• Europe– Austria & alpine region– Switzerland, Germany– Great Britain– Sweden– Eastern Europe
• Asia– India– China– Singapore
• USA• Know-How: worldwide
ABT = Tunnel projects around the world
ALPINE BeMo Tunnelling (ABT)
ArbeitsklausurWagrain, 15./16.04.2010
• ~ 40 000 meters of tunnels/galleries each year• constructor and designer
– specialized in complex 3D-models and analysis of underground structures
Tunnel projects around the world
ALPINE BeMo Tunnelling (ABT)
ALPINE BeMo Tunnelling
ArbeitsklausurWagrain, 15./16.04.2010
City Tunnel Leipzig, Lot BLeipzig, Germany
ALPINE BeMo Tunnelling
ArbeitsklausurWagrain, 15./16.04.2010
ALPINE BeMo Tunnelling (ABT)
ALPINE & BeMo: ABT = a global tunnel company
ABT = tunnel projects around the world
ABT = in-house tunnel design capability
ABT = know-how as part of tunnel business
ALPINE BeMo Tunnelling
ArbeitsklausurWagrain, 15./16.04.2010
Outline
• Motivation• Aging concrete constitutive model• Parameter identification approach• Back calculation of in situ measurements• Conclusions
Modelling aging shotcrete: parameter identification and application
ArbeitsklausurWagrain, 15./16.04.2010
• modelling time dependent behaviour (creep) of „young“/aging shotcrete is important for the design of outer lining in tunnelling
• use of zsoil-aging concrete model for modelling aging shotcrete– many material parameters are required – not all of them have physical meanings difficult to obtain from
measurements
• parameter identification is of special importance• use of aging concrete model for back calculation of in
situ measurements
Motivation
ArbeitsklausurWagrain, 15./16.04.2010
Outline
• Motivation• Aging concrete constitutive model• Parameter identification approach• Back calculation of in situ measurements• Conclusions
ArbeitsklausurWagrain, 15./16.04.2010
Aging concrete
ArbeitsklausurWagrain, 15./16.04.2010
Aging concrete
• aging concrete model requires a large number of material parameters
• e.g. 3 Maxwell units, 7 maturity points 24 parameters to identify
• creep behaviour can be modelled • however dependence of strength can not be modelled
viscoplastic model required • is it possible to model time dependent concrete strength
within zsoil?
ArbeitsklausurWagrain, 15./16.04.2010
Outline
• Motivation• Aging concrete constitutive model• Parameter identification approach• Back calculation of in situ measurements• Conclusions
ArbeitsklausurWagrain, 15./16.04.2010
Parameter identification approachOptimization problem
• deterministic model relates set of responses x = x(p) and model parameters p
• given measurements x* = [x1* … xm*]T from experiments• objective function for minimization problem
J = (x* - x)T W (x* - x)• optimization using dakota - toolkit
ArbeitsklausurWagrain, 15./16.04.2010
Parameter identification approachDakota toolkit (taken from http://dakota.sandia.gov)
ArbeitsklausurWagrain, 15./16.04.2010
Parameter identification approachDakota toolkit (taken from http://dakota.sandia.gov)
ArbeitsklausurWagrain, 15./16.04.2010
Parameter identification approachDakota – zsoil
dakotaglobal optimization or nonlinearleast square methods
parameterse.g. C1…Cn
simulation - zsoilpython script adapts zsoiltemplate input file
responsemetrics
ArbeitsklausurWagrain, 15./16.04.2010
Parameter identification approachzsoil template file
dakotaglobal optimization or nonlinearleast square methods
parameterse.g. C1…Cn
simulation - zsoilpython script adapts zsoiltemplate input file
responsemetrics
ArbeitsklausurWagrain, 15./16.04.2010
Parameter identification approachzsoil template file
aging concrete material model
load = 1 MPa
• creep test modelled as single element test• load is adjusted within a python script by modifying its load functions
ArbeitsklausurWagrain, 15./16.04.2010
Parameter identification approachDakota – zsoil communication
dakotaglobal optimization or nonlinearleast square methods
parameterse.g. C1…Cn
simulation - zsoilpython script adapts zsoil templateinput file
responsemetrics
• automatic adaption of zsoil input file and evaluation of output-file is important• communication dakota – zsoil via python scripts
ArbeitsklausurWagrain, 15./16.04.2010
Parameter identification approachStructure of python script
ArbeitsklausurWagrain, 15./16.04.2010
Parameter identification approachCalling zsoil
windows pop up for each zsoil-run• sometimes in the background• but sometimes in the foreground• how to avoid pop up windows?
ArbeitsklausurWagrain, 15./16.04.2010
Parameter identification approachBack calculation of creep tests
• creep test data taken from:Zachow (1995): Dimensionierung zweischaliger Tunnel im Fels auf
der Grundlage von in-situ Messungen• used creep tests with constant loads of 5 and 7 MPa for back
calculation• two Maxwell units for aging concrete model were sufficient for this
simple tests• nevertheless 9 parameter have to be identified
parameter identification approach can be used for other constitutive models as well
other parameters (e.g. loads, geometrical parameters, …) could also be identified / optimized
ArbeitsklausurWagrain, 15./16.04.2010
Parameter identification approachBack calculation of creep tests
parameter identification usingone test (5 MPa) withnonlinear least squaresmethod
parmeter identificationusing two tests(5 and 7 MPa)
time [h] time [h]
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ArbeitsklausurWagrain, 15./16.04.2010
Outline
• Motivation• Aging concrete constitutive model• Parameter identification approach• Back calculation of in situ measurements• Conclusions
ArbeitsklausurWagrain, 15./16.04.2010
Back calculation of in situ measurements
• deformations of outer lining are measured every 10 – 20 tunnelmeters
• valuable data for– specification of support for the following excavation steps– back calculation of utilization factor of outer lining– back calculation of loading for design of inner lining
• utilization factor: „stress / strength“, similar to zsoil-stress level– Rokahr, R., and Zachow, R. (1997): A new method for the daily monitoring of the
stress intensity of a sprayed concrete lining; Rock and Soil Engineering, 15(6); 430-434 (in German)
– Hellmich C., and Mang, H. (2005): Shotcrete Elasticity Revisited in the Framework of Continuum Micromechanics: From Submicron to Meter Level
– Tunnel:Monitor®: www.tunnelmonitor.com
ArbeitsklausurWagrain, 15./16.04.2010
Back calculation of in situ measurementsDeformation measurement
ArbeitsklausurWagrain, 15./16.04.2010
Back calculation of in situ measurementsDeformation measurement
ArbeitsklausurWagrain, 15./16.04.2010
Back calculation of in situ measurementsFE model
• cross section modelled with „shell one layer“ – elements, 1m length
• material: aging concrete model• interpolation of measurement data in
time and space– adapting existence functions– adapting load functions of boundary
conditions– done with python scripts
• results (forces, moments) are used for calculation of the utilization factor
ArbeitsklausurWagrain, 15./16.04.2010
Back calculation of in situ measurementsResults: membrane forces and moments
membrane force-XX moment-XX
ArbeitsklausurWagrain, 15./16.04.2010
Back calculation of in situ measurementsResults: save element results in csv-file
• recorded postprocessing macro to extract results in csv-file• python script adapts csv-file name and steps (from *.his file)• tried to run macro from python script (and command line)
• but only Z_POST3D starts, macro is not played and Z_POST3D not closed (same behaviour when running command from command line)
• how to play the record automatically and close Z_POST3D afterwards? (important for automatic calculation of utility factor...)
ArbeitsklausurWagrain, 15./16.04.2010
Back calculation of in situ measurementsResults: utilization factor
• aim is the calculation of the utilization factor for cross sections over time
• ongoing work ...
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ArbeitsklausurWagrain, 15./16.04.2010
Outline
• Motivation• Aging concrete constitutive model• Parameter identification approach• Back calculation of in situ measurements• Conclusions
ArbeitsklausurWagrain, 15./16.04.2010
Summary• creep behaviour of shotcrete in early age can be modelled with
zsoil’s aging concrete model• zsoil can be used within an optimization framework by adapting zsoil
input and output files• back calculation of the utilization factor of the outer lining from
measurements can be done with the aging concrete model
Conclusions
Issues• is it possible to model time dependent concrete strength within
zsoil?• windows pop up when calling zsoil from python script • calling Z_POST3D with a macro: how to do?