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Strain-Based Stability Analysis of Earthen Embankments Subjected to Cyclic Hydraulic Loading Associated with Extreme Events

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Strain-Based Stability Analysis of Earthen Embankments Subjected to Cyclic Hydraulic Loading Associated with Extreme Events/ Rowshon Jadid.
Author:	Jadid, Rowshon,
Description:	1 electronic resource (167 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 82-09, Section: B.
Contained By:	Dissertations Abstracts International82-09B.
Subject:	Hydraulic engineering. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=28306142
ISBN:	9798698599296

Strain-Based Stability Analysis of Earthen Embankments Subjected to Cyclic Hydraulic Loading Associated with Extreme Events
Jadid, Rowshon,

Strain-Based Stability Analysis of Earthen Embankments Subjected to Cyclic Hydraulic Loading Associated with Extreme Events [electronic resource] /Rowshon Jadid. - 1 electronic resource (167 pages)

Source: Dissertations Abstracts International, Volume: 82-09, Section: B.

Repeated rapid drawdown (RDD) and rapid rise in water level during extreme events lead to progressive development of plastic shear strain zones within the earth embankments with subtle, rather than obvious, visible signs of distress. The traditional analysis approach within the framework of limit equilibrium method does not account for the accumulated permanent deformation with repeated hydraulic loading. This study investigates the effect of repeated rise and fall of water levels (representing severe flood or drawdown cycles) on the stability performance aspects of embankment levees and dams. Analysis are performed using unsaturated coupled transient seepage method and non-liner advanced elasto-plastic constitutive relation in finite element (FE) program PLAXIS. Results show a progressive development of internal distress within the embankment as the number of hydraulic cycles is increased. This internal distress level is quantified in terms of level of shear strain. A simple linear relationship between the shear strain and monitorable deformation at the toe of the embankment is developed as a function of the geometry of the slope. This relationship provides a simple means to estimate the performance limit state that corresponds to the instability of embankment slopes, and the critical shear strain at the embankment toe, using the stress-strain data obtained from triaxial testing. Results from the parametric study using numerical analyses show a good agreement with the proposed analytical criterion. The proposed criterion is also compared with data from the field studies by others and reasonable good agreement is obtained.This study also assesses three remedial methods representing three different mechanisms to reduce instability risk from the progressive development of deformation. These remedial methods improve stability by providing reinforcement on the upstream slope (soil nails), reducing slope height to decrease the shear stress (bench), and lowering phreatic surface to decrease pore water pressure (drainage blanket). They are analyzed and compared in terms of probability of exceeding the predefined ultimate limit state, where the limit state is associated with horizontal deformation at slip surface toe that can be readily monitored in the field through periodic surveying. Given the set of conditions used in this study, excavating a bench appears to be the most effective measure in terms of associated risk among the three analyzed remedial methods due to the anticipated lower probability of exceedance and shallower potential slip surface, which deems to cause lower consequence.For comparative study, pore water pressure and stability factor of safety are also calculated using partially coupled and uncoupled transient seepage analysis. The uncoupled seepage analysis is implemented in PLAXIS, whereas the partially coupled seepage analysis and stability analysis are performed using FE program SEEP/W and limit equilibrium software SLOPE/W, respectively. Results are presented and discussed on how pore water pressure predictions from different models significantly affect the magnitude of stability factor of safety, the maximum thickness of potential slip surface, and the required time to establish steady-state conditions. 

English

ISBN: 9798698599296Subjects--Topical Terms:

848144
Hydraulic engineering.
Subjects--Index Terms:

Strain

Strain-Based Stability Analysis of Earthen Embankments Subjected to Cyclic Hydraulic Loading Associated with Extreme Events
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245 1 0 $a Strain-Based Stability Analysis of Earthen Embankments Subjected to Cyclic Hydraulic Loading Associated with Extreme Events $c Rowshon Jadid. $h [electronic resource] /
264 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2020
300 $a 1 electronic resource (167 pages)
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500 $a Source: Dissertations Abstracts International, Volume: 82-09, Section: B.
500 $a Advisors: Bolinaga, Celso Castro; Rahman, Shamim; Montoya, Brina; Gabr, Mohammed.
502 $b Ph.D. $c North Carolina State University $d 2020.
520 # $a Repeated rapid drawdown (RDD) and rapid rise in water level during extreme events lead to progressive development of plastic shear strain zones within the earth embankments with subtle, rather than obvious, visible signs of distress. The traditional analysis approach within the framework of limit equilibrium method does not account for the accumulated permanent deformation with repeated hydraulic loading. This study investigates the effect of repeated rise and fall of water levels (representing severe flood or drawdown cycles) on the stability performance aspects of embankment levees and dams. Analysis are performed using unsaturated coupled transient seepage method and non-liner advanced elasto-plastic constitutive relation in finite element (FE) program PLAXIS. Results show a progressive development of internal distress within the embankment as the number of hydraulic cycles is increased. This internal distress level is quantified in terms of level of shear strain. A simple linear relationship between the shear strain and monitorable deformation at the toe of the embankment is developed as a function of the geometry of the slope. This relationship provides a simple means to estimate the performance limit state that corresponds to the instability of embankment slopes, and the critical shear strain at the embankment toe, using the stress-strain data obtained from triaxial testing. Results from the parametric study using numerical analyses show a good agreement with the proposed analytical criterion. The proposed criterion is also compared with data from the field studies by others and reasonable good agreement is obtained.This study also assesses three remedial methods representing three different mechanisms to reduce instability risk from the progressive development of deformation. These remedial methods improve stability by providing reinforcement on the upstream slope (soil nails), reducing slope height to decrease the shear stress (bench), and lowering phreatic surface to decrease pore water pressure (drainage blanket). They are analyzed and compared in terms of probability of exceeding the predefined ultimate limit state, where the limit state is associated with horizontal deformation at slip surface toe that can be readily monitored in the field through periodic surveying. Given the set of conditions used in this study, excavating a bench appears to be the most effective measure in terms of associated risk among the three analyzed remedial methods due to the anticipated lower probability of exceedance and shallower potential slip surface, which deems to cause lower consequence.For comparative study, pore water pressure and stability factor of safety are also calculated using partially coupled and uncoupled transient seepage analysis. The uncoupled seepage analysis is implemented in PLAXIS, whereas the partially coupled seepage analysis and stability analysis are performed using FE program SEEP/W and limit equilibrium software SLOPE/W, respectively. Results are presented and discussed on how pore water pressure predictions from different models significantly affect the magnitude of stability factor of safety, the maximum thickness of potential slip surface, and the required time to establish steady-state conditions. 
546 $a English
590 $a School code: 0155
650 # 4 $a Hydraulic engineering. $3 848144
650 # 4 $a Geophysics. $3 686174
650 # 4 $a Geological engineering. $3 1186227
653 # # $a Strain
653 # # $a Stability analysis
653 # # $a Earthen embankments
653 # # $a Cyclic hydraulic loading
653 # # $a Extreme event
690 $a 0466
690 $a 0218
690 $a 0373
690 $a 0467
710 2 # $a North Carolina State University. $3 845424
720 1 $a Bolinaga, Celso Castro $e degree supervisor.
720 1 $a Rahman, Shamim $e degree supervisor.
720 1 $a Montoya, Brina $e degree supervisor.
720 1 $a Gabr, Mohammed $e degree supervisor.
773 0 # $t Dissertations Abstracts International $g 82-09B.
790 $a 0155
791 $a Ph.D.
792 $a 2020
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=28306142