Workshop of the TC302 - Forensic Geotechnical Engineering

Dolexpert - GeotechnikaDolexpert - Geotechnika 11

Workshop of the TC302 - Forensic Geotechnical EngineeringWorkshop of the TC302 - Forensic Geotechnical Engineering

FAILURES, DISPUTES, CAUSES AND SOLUTIONS IN GEOTECHNICSFAILURES, DISPUTES, CAUSES AND SOLUTIONS IN GEOTECHNICS

24-25 September 2010, Budapest, Hungary24-25 September 2010, Budapest, Hungary

UNDERSTANDING BEHAVIOUR OF UNDERSTANDING BEHAVIOUR OF DISTRESSED STRUCTURES THROUGH DISTRESSED STRUCTURES THROUGH

MEASURING AND MODELLINGMEASURING AND MODELLING

MARTA DOLEMARTA DOLEZZALOVALOVAADolexpert – Geotechnika, PrDolexpert – Geotechnika, Prague, Czech Republicague, Czech Republic

Robust numerical models fitting the long-term measurement results Robust numerical models fitting the long-term measurement results

represent a powerfull tool for pinpointing causes of distressrepresent a powerfull tool for pinpointing causes of distress


• Numerical Numerical AAnalysis of nalysis of UUnusual nusual BBehaviour ehaviour of of ZZermanice ermanice DDamam (36 m, 1952 –1958, Czech (36 m, 1952 –1958, Czech Republic)Republic)

Tomaš SkokanTomaš SkokanDalibor KratochvilDalibor KratochvilFrantišek GlacFrantišek Glac

Jiri SvancaraJiri SvancaraDalibor BilekDalibor BilekVaclav TornerVaclav Torner

Marta DolezalovaMarta DolezalovaIvo HladikIvo HladikVlasta ZemanovaVlasta Zemanova

Stanislav NovosadStanislav NovosadKarel PekarekKarel Pekarek

TEAM:TEAM:

CASE STUDY:CASE STUDY:

PROBLEM:PROBLEM:• Concerns about the stability of the concrete dam due to long-term Concerns about the stability of the concrete dam due to long-term

tilting, heave and uneven displacements detected by monitoringtilting, heave and uneven displacements detected by monitoring

SOLUTION:SOLUTION:• Develpoment of a 3D model of the dam and its foundation fitting the Develpoment of a 3D model of the dam and its foundation fitting the

monitoring results and simulating the history of the dam including monitoring results and simulating the history of the dam including

the distress stagesthe distress stages


OUTLINE OF THE PRESENTATIONOUTLINE OF THE PRESENTATION

• The dam and dam siteThe dam and dam site

• Measurement resultsMeasurement results

• Modelling conceptModelling concept

• Stability assessmentStability assessment

• Modelling formation of the valley Modelling formation of the valley

• 3D model of3D model of the dam and its foundation the dam and its foundation

• ConclusionsConclusions

ZZERMANICEERMANICE CONCRETE DAM CONCRETE DAM:: reservoir of 26 reservoir of 26 mil. mmil. m3 3

for water supply of Ostrava industrial regionfor water supply of Ostrava industrial region


ZZERMANICEERMANICE CONCRETE DAM CONCRETE DAM• geological conditionsgeological conditions

• properties of bedrockproperties of bedrock• characteristic cross sections of the damcharacteristic cross sections of the dam


ZZERMANICEERMANICE CONCRETE DAM CONCRETE DAM • deformation modulus of the bedrock deformation modulus of the bedrock • differential movements of the damdifferential movements of the dam


ZERMANICE DAMZERMANICE DAM• Heave Heave of dam sections founded on weak marly shale of dam sections founded on weak marly shale [[mm]mm]

1964 1970 1980 1990 2000

Heave [mm]


ZERMANICE DAMZERMANICE DAM• Tilt [mm/10 m height] - pendulum in Section 1 – 1’Tilt [mm/10 m height] - pendulum in Section 1 – 1’

1966 1970 1980 1990 2000

Tilt [mm/10m ]


• Uneven hUneven horizontal displacements of the dam crestorizontal displacements of the dam crest

ZERMANICE DAMZERMANICE DAM

1955 2000

Horizontal displacement [mm] Section 1-1‘ on weak marly shale, 60 mmSection 1-1‘ on weak marly shale, 60 mm

Section 2-2‘ on competent volcanic rock, 20 mmSection 2-2‘ on competent volcanic rock, 20 mm


WORKING HYPOTHESISWORKING HYPOTHESIS• based on the analysis of geological conditions and based on the analysis of geological conditions and

monitoring results andmonitoring results and• on the geological-historical study of Q. Zaruba (1956), on the geological-historical study of Q. Zaruba (1956),

whichwhich highlightedhighlighted the crucial role ofthe crucial role of viscoplastic flow of viscoplastic flow of the marly shale in formation of the valleythe marly shale in formation of the valley

1.1. Possible reason of the unexpected behaviour of the dam Possible reason of the unexpected behaviour of the dam isis viscoplastic flow of the marly shale induced by viscoplastic flow of the marly shale induced by reservoir fillingreservoir filling causing overstress, which exceeded of causing overstress, which exceeded of visco-plastic threshold of the marly shale.visco-plastic threshold of the marly shale.

2.2. The visco-plastic parameters of the marly shale could be The visco-plastic parameters of the marly shale could be estimated by estimated by simulating the rheological process of simulating the rheological process of the formation of the valley.the formation of the valley.

ZERMANICE DAMZERMANICE DAM, 36 m, 1952-1958, 36 m, 1952-1958


MODELLINGMODELLING CONCEPT CONCEPT-- step-by-step simulation of the observed step-by-step simulation of the observed

behaviourbehaviour by a series of 2D FEM models by a series of 2D FEM models

LOCAL 2D FEM MODELSLOCAL 2D FEM MODELS

Dam section on the weak marly shaleDam section on the weak marly shale• 1a : calibration of mechanical / hydraulic 1a : calibration of mechanical / hydraulic

parametersparameters• 1b : stability analysis1b : stability analysis• 1c : calibration of thermal parameters1c : calibration of thermal parameters

Dam section on the tescheniteDam section on the teschenite• 2a : calibration of mechanical / hydraulic 2a : calibration of mechanical / hydraulic

parametersparameters• 2b : stability analysis2b : stability analysis


- calibration of rheological parameterscalibration of rheological parameters

REGIONAL 2D FEM MODELSREGIONAL 2D FEM MODELS3a :3a : erosion of the riverbed and bulging oferosion of the riverbed and bulging of the the

marly shalemarly shale

3b : viscoplastic flow of disturbed shale during 3b : viscoplastic flow of disturbed shale during constructionconstruction

of the damof the dam

3c :3c :influence of the reservoir on viscoplastic flow of influence of the reservoir on viscoplastic flow of the disturbed shale during operation of the the disturbed shale during operation of the damdam3D FEM MODEL3D FEM MODEL

4 :4 : synthesis, safety assessment and prediction of the synthesis, safety assessment and prediction of the dam performancedam performance

MODELLINGMODELLING CONCEPT CONCEPT (continued)(continued)


• Section of the dam on weak marly shale• Strain localization and slip at strength reduction factor

F = 2.5

ZERMANICE DAMZERMANICE DAM: stability assessment: stability assessment


FORMATION OF THE LUCINA FORMATION OF THE LUCINA RIVERBED IN GEOLOGICAL TIMERIVERBED IN GEOLOGICAL TIME

Geological-historical study of Academic Zaruba, 1956:Geological-historical study of Academic Zaruba, 1956:• erosion of the valley, depth: 25 merosion of the valley, depth: 25 m• viscoplastic flow and bulging of marly shaleviscoplastic flow and bulging of marly shale• sliding, breaking and subsidence of the teschenite sill: ~ 13 m sliding, breaking and subsidence of the teschenite sill: ~ 13 m • duration of the event cca 15 000 yearsduration of the event cca 15 000 years

Teschenite sill before erosion of the riverbed (–25 000 B.C.)Teschenite sill before erosion of the riverbed (–25 000 B.C.)

Teschenite

Cretaceous marly shale

Pleistoceneous gravel

Teschenite blocks after erosion of the riverbed (–10 000 B.C.)Teschenite blocks after erosion of the riverbed (–10 000 B.C.)


REGIONALREGIONAL FEM FEM MODEL MODEL AND SOLUTION AND SOLUTION STRATEGYSTRATEGY2D FEM2D FEM MESHMESH

EXCAVATION STAGES SIMULATING THE EROSION OF THE EXCAVATION STAGES SIMULATING THE EROSION OF THE VALLEYVALLEY

00 1800 1800 mm

SOLUTION STRATEGY:SOLUTION STRATEGY:

• elastoplastic simulation of the process using strength reduction methodelastoplastic simulation of the process using strength reduction method

• determination of the viscoplastic parametersdetermination of the viscoplastic parameters c cvpvp ,, vpvp ,,

• viscoplastic simulation of the processviscoplastic simulation of the process delayed collapse resulting in slidingdelayed collapse resulting in sliding


FEM SIMULATION OF THE VISCOPLASTIC FEM SIMULATION OF THE VISCOPLASTIC FLOW ACROSS THE VALLEYFLOW ACROSS THE VALLEY

excavation of the riverbed simulating erosionexcavation of the riverbed simulating erosion viscoplastic flow and bulging of the soft marly shale due toviscoplastic flow and bulging of the soft marly shale due to overstressoverstress induced by erosion induced by erosion washing away the disturbed marly shale from the riverbedwashing away the disturbed marly shale from the riverbed


RESULTS OF THE FEM SIMULATIONRESULTS OF THE FEM SIMULATION• bulging of the marly shale and subsidence of the teschenite

blocks due to erosion of the riverbed • cumulated displacement vectors

Teschenite blocks: horizontal displacement of 14 m and subsidence of 10 m (10 to 13 m according to the geological study)


3D MODEL OF ZERMANICE DAM3D MODEL OF ZERMANICE DAM- horizontal displacements induced by the horizontal displacements induced by the first filling of the reservoirfirst filling of the reservoir- Section 1 - 1’: calculated 18.5 mm / measured 15.5 mmSection 1 - 1’: calculated 18.5 mm / measured 15.5 mm Section 2 - 2’: calculated 8.6 mm / measured 10.5 mmSection 2 - 2’: calculated 8.6 mm / measured 10.5 mm

DOF = 389 656Horizontal displacements [m]


3D MODEL OF ZERMANICE DAM3D MODEL OF ZERMANICE DAM- highly uneven horizontal movements of the dam sections highly uneven horizontal movements of the dam sections founded on soft marly shale and on competent teschenitefounded on soft marly shale and on competent teschenite- comparison of the calculated and measured displacements due to comparison of the calculated and measured displacements due to viscoplastic flowviscoplastic flow of the marly shale of the marly shale (1959 – 2000)(1959 – 2000)


3D MODEL OF ZERMANICE DAM3D MODEL OF ZERMANICE DAM• prediction of the prediction of the horizontal movements of the dam horizontal movements of the dam

sections on sections on the the soft marly shale soft marly shale up to 2060up to 2060


3D MODEL OF ZERMANICE DAM3D MODEL OF ZERMANICE DAM• superposition of the superposition of the viscoplastic flow across the valleyviscoplastic flow across the valley induced induced byby

erosion of the riverbed erosion of the riverbed and and viscoplastic flow along the valleyviscoplastic flow along the valley

induced induced byby reservoir filling reservoir filling ((reservoir operationreservoir operation from 1959 to 2000from 1959 to 2000))

2 1’

1

2’


1.1. TThe unusual performance of the dam is caused by he unusual performance of the dam is caused by superposition of superposition of viscoplastic flow of marly shaleviscoplastic flow of marly shale in two in two directionsdirections: along the valley induced by reservoir filling : along the valley induced by reservoir filling and across the valley and across the valley induced by the erosion of the induced by the erosion of the riverbed in geological time.riverbed in geological time.

2.2. Heave Heave of the dam is caused of the dam is caused byby viscoplastic flow viscoplastic flow across across the valleythe valley, while , while tilting a differential movementstilting a differential movements occur occur due to viscoplastic flow along the valleydue to viscoplastic flow along the valley..

3.3. NNoo immediate safety measureimmediate safety measures s butbut only extension of only extension of the downstream the downstream embankment embankment to damp the to damp the viscoplastic viscoplastic flowflow along the valley was recommended. along the valley was recommended.

4.4. The analysis confirms that The analysis confirms that measuring and modelling measuring and modelling are effective toolsare effective tools for pinpointing cause of distress of for pinpointing cause of distress of civil engineering structures.civil engineering structures.

CONCLUSIONSCONCLUSIONS


APPENDIXAPPENDIX


BASIC RELATIONS OF THE PDEP MODEL BASIC RELATIONS OF THE PDEP MODEL (1)(1) ((Dolezalova 1985, 1992Dolezalova 1985, 1992))

Stress path groupsStress path groupsStress path identifiers and Stress path identifiers and switch functionsswitch functions

Region with different constitutive Region with different constitutive relations of Molenkamp’s Double relations of Molenkamp’s Double Hardening Model(1983)Hardening Model(1983)

Relations for calculating tangential Relations for calculating tangential deformation characteristics Edeformation characteristics Ett, , tt


BASIC RELATIONS OF THE PDEP MODEL BASIC RELATIONS OF THE PDEP MODEL (2)(2)

c, c, , , resres, , , , tt - cohesion, angle of shearing resistance, residual angle of shearing resistance, angle of - cohesion, angle of shearing resistance, residual angle of shearing resistance, angle of

dilation, tensile strengthdilation, tensile strength EEpp, E, Eunlunl, E, Etenten, E, Emaxmax - tangent deformation modulus at loading, unloading, tension and the maximum tangent - tangent deformation modulus at loading, unloading, tension and the maximum tangent

deformation modulusdeformation modulus pp, , max max - initial and maximum tangent values of Poisson´s ratio - initial and maximum tangent values of Poisson´s ratio ii00, , , , oo

- initial shear strength mobilization, factor determining the minimum tangent modulus (E- initial shear strength mobilization, factor determining the minimum tangent modulus (E minmin = = EEpp) )

and referent pressure and referent pressure

CalculatiCalculation ofon of E Ett, , tt

Parameters:Parameters:

;;

;;

Mohr- Coulomb yield and Mohr- Coulomb yield and failure criterionfailure criterion

- shear strength mobilization

Dolexpert - GeotechnikaDolexpert - Geotechnika 29291 – marly shale1 – marly shale 2 – partly disturbed marly shale 2 – partly disturbed marly shale 3 – disturbed marly shale 3 – disturbed marly shale

Deformational and strength characteristics of marly shaleDeformational and strength characteristics of marly shale

ZERMANICE DAMZERMANICE DAM 2D FEM model of the dam section on disturbed marly shale2D FEM model of the dam section on disturbed marly shale

foundation slabfoundation slab

grout curtaingrout curtain

disturbed marly shaledisturbed marly shale

partly disturbed marly shalepartly disturbed marly shale

marly shalemarly shale

damdamembankmentembankment


MULTIFACE VISCOPLASTIC FLOWMULTIFACE VISCOPLASTIC FLOW1.1. Viscoplastic strain rateViscoplastic strain rate (Perzyna, 1966; Zienkiewicz & Pande, (Perzyna, 1966; Zienkiewicz & Pande, 1977)1977)QQ – viscoplastic potential– viscoplastic potential

FF – viscoplastic threshold– viscoplastic threshold (yield surface) (yield surface) – – fluidity parameterfluidity parameter (1/ (1/))yy = = 11, .... , .... kk ; ; kk – number of surfaces– number of surfaces

k

y

y

yyy

k

y

p

y

pQ

F11

)(

2. Viscoplastic flow with two surfaces2. Viscoplastic flow with two surfaces

3.3. Parameters to be determined:Parameters to be determined:

viscoplastic threshold Fviscoplastic threshold F ccvpvp , , vpvp 10 to 20 % of strength10 to 20 % of strength

fluidity parameter fluidity parameter viscoplastic strain rateviscoplastic strain rate

overstressoverstress

fluidity parameter of rock fluidity parameter of rock saltsalt

Workshop of the TC302 - Forensic Geotechnical Engineering

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