dr. arindam dey presentations... · sherard (1973) suggested that the existing closed cracks can...

Short Course

Finite Element Analysis of Static and Dynamic

Soil-structure Interaction of Geosystems

Department of Civil Engineering, NIT Warangal

Dr. Arindam DeyAssociate Professor

Geotechnical Engineering Division

Department of Civil Engineering

IIT Guwahati

Introduction Dams are structural barriers

Construction of earthen dams in the north-eastern region of

India

-regional flood management measure

-incessant rainfall and encompasses around 12% of the

total flood area of the country (Das et al., 2017)

Chief drawback of earthen dams

-prone to get overtopped

-seepage, internal erosion, piping, clogging, cracking

Prevention of failures of earthen dams and embankments

Drainage layers -expected to protect the earthen dams

Instability of dams due to hydraulic fractures (Yang et al.,

2004) 207-01-2021 Short Course, NIT Warangal

Failures of Earthen Dams Across the World

307-01-2021 Short Course, NIT Warangal

Fenton and Griffiths (1997) The influence of spatial variability of the permeability of the dam on the development of internal

hydraulic gradients was attempted. It was found that the spatial variability of the permeability does

lead to a probability of higher internal gradients.

Reddi et al. (2000) Studied the reduction of permeability of the filters due to clogging. It was observed that an increase

in influent particle concentration results in faster reduction of the filter permeability. However, the

filter performance was not affected by the flow rate.

Reboul et. al. (2010) A method was proposed to compute the constriction size distribution of model granular filters taking

into account the relative density of the material.

Sherard (1973) Suggested that the existing closed cracks can jack open under certain conditions of reservoir pressure

acting on the upstream face of the core in a zoned earthen dam.

Vaughan (1976) Introduced the term “wet cracks” for the cracks formed during or after the reservoir rise-up. The

occurrence of tensile failure was observed when the seepage pressure was applied rapidly to an

already existing initial crack, or imperfection, leading to the failure of the dam.

Leonards and Davidson (1984),

Mesri and Ali (1988)

Defined saturation settlement as the cause of core cracking due to hydraulic fracturing. Saturation

settlement develops during the filling of a reservoir, when the poorly compacted soil or pervious

zones and layers (comprising loose material) becomes saturated and consolidates under their own

weight, before the dry or denser soil arches over it and gets the chance to saturate and collapse. A

discontinuity or a crack is developed along the position of the phreatic line. Any subsequent increase

in water level allows the entry of water into this crack enabling the erosion to occur. Such collapse

can be either sudden or gradual.

Past Studies


5

Basic Methodology Considered in Numerical Simulation

Seepage Analysis : Seep/w module

Deformation Analysis : Sigma/w module

Stability Analysis : Slope/w module

𝜕

𝜕𝑥𝑘𝑥𝜕𝐻

𝜕𝑥+

𝜕

𝜕𝑦𝑘𝑦

𝜕𝐻

𝜕𝑦+ 𝑄 =

𝜕𝜃

𝜕𝑡

𝑋 = 𝐸𝜆𝑓 𝑥 , Morgenstern and Price (1965)

b s nK a F F F F

where, [K] is the element characteristic (or stiffness) matrix, {a} is the nodal incremental displacement vector, {F} is the applied nodal incremental

force, {Fb} is the incremental body force vector, {Fs} is the force vector due to surface boundary incremental pressures, and {Fn} is the vector of

concentrated nodal incremental forces.

where, f(x) is a function, λ is a scaling factor, E is the interslice normal force and X is the interslice shear force

where, H is the total head, kx, ky are the hydraulic conductivities in the Cartesian directions, Q is the applied boundary flux, θ is the volumetric water

content, and t is the elapsed time.


GeoStudio 2012

• A fully-automated robust unstructured meshing (employing element compatibility)

-generated on the basis of the defined geometry,

-can be altered or subjected to further local or global refined as per the necessity

• Different type of finite element mesh patters namely,

-Quads and Triangles, Triangles only, Rectangular grid of quads, Triangular grid of Quads /

Triangles

• Unstructured mesh comprising ‘quad and triangle’ is utilized

-selected element type conforms to the 4-noded quadrilaterals and 3-noded triangles,

respectively

Seep/w Simulations

-constant total head (H) and total head (H|t|) boundary conditions

Sigma/w Simulations

-base of the model is restrained from displacement in both the directions,

-far lateral boundaries are restrained from horizontal displacement but are kept free from

vertical restraint

-fluid pressure boundary is used to specify the elevation of the water surface

Slope/w Simulations

-‘Entry and Exit’ method of defining the slip circles and identify the critical slip circle is used

Meshing and Boundary Conditions


Seep/w

The embankment and core

-‘Saturated / Unsaturated’ material model

The foundation

-‘Saturated Only’ material model

Sigma/w

Linear Elastic material model

Elastic Perfectly Plastic material model

Slope/w

Mohr-Coulomb failure criterion

Material models

7

Stages of Analyses

Steady state seepage analysis : To set up the initial pore water pressures and total head conditions

In-situ analysis : To set up the initial stress conditions

Load/Deformation analysis : To simulate the staged construction of dams

Coupled Stress/PWP analysis : To generate - different drain clogging scenarios, reservoir operating conditions

Stability analysis : Stress based in Slope/w07-01-2021 Short Course, NIT Warangal

Numerical Modeling of Earthen Dam: Validation With Field Data

Evolution of Finite Element Method (FEM) from a research tool into a daily engineering tool

-application for the analysis of geotechnical engineering problems

Many advantages provided by the usage of FEM, but it also suffers from some limitations

-simplified representation of the actual soil behaviour forms one of the main limitations

Some features of soil behaviour will not be captured by the model

Validation of the numerical models with the actual field scenario becomes essential

Validation confirms the accuracy with which the model captures the reality

Numerical model simulating reservoir drawdown condition in an earthen dam

was validated with real field condition


MODEL FOR THE STUDY(Paton and Semple, 1961)

Typical dam section of Glen Shira Dam,

Scotland (Pinyol et. al., 2016)

9

c

(kPa)

φ

(degree)

γ

(kN/m3)

E

(kPa)

k

(m/s)

Morainic fill 15 25 18 5000 10-8

Graded filter 0 25 16 10000 10-1

Core wall 12 20 18 25000 10-18

Rockfill 0 30 16 15000 10-3

Foundation 12 18 20 30000 10-16

MATERIAL PROPERTIES(USBR 2003; USBR 2014; Pinyol et. al., 2016;

Paton and Semple, 1961; Geotechdata.info, 2013)

Rate of reservoir drawdown (function of total head with time)07-01-2021 Short Course, NIT Warangal

RESULTS AND DISCUSSIONS

10

Average percentage difference between the measured values

and Geostudio simulations is 10%


(a) (b)

(c)

• Total head contour values and distribution

• Results from Geostudio gives very similar nature

• Compared with the computed and interpolated

values

Code_Bright (Alonso & Pinyol, 2016) Paton and Semple, 1961

Geostudio results


Dams and seepage

50% of all dam failures are attributed to excess seepage (Fell and Foster, 2000)

Application of filters and drains have been a common method to control the seepage flow (USBR, 2003)

But what if these drains and filters undergo clogging…

Dam failures associated drain clogging (Vaughan and Soares 1982; Von Thun 1985; Peck 1990; Vick 1996)

Fonte Santa tailings dam in Northeast Portugal, failure on November 27, 2006 (Franca et al., 2008).

Clogging is a major public concern limiting the lifetime of the structures

In earthen dams clogging is a serious issue, however few works are done to study the response of the dams due to clogging

12

RESPONSE OF HOMOGENEOUS EARTHEN DAM SUBJECTED TO

CLOGGING OF DRAINAGE BLANKET


MODEL GEOMETRY Earth dam models with dimensions as per IS 12169:1987

13

c

(kPa)

φ

(degree)

γ

(kN/m3)

E

(kPa)

k

(m/s)

Embankment 10 25 20 15000 10-7

Foundation 15 20 20 30000 10-10

Drain 2 30 18 12000 10-2

Clog 10 25 20 15000 10-7

MATERIAL PROPERTIES

(IS 12196:1987; USBR 2014; NAVFAC Design Manual 7.2, 1982, Geotechdata.info, 2013)


SCENARIOS INVESTIGATED IN THE STUDY

Dam without any drainage blanket (NDC)

Dam with fully functional drainage blanket (FDC)

Dam with clogged drainage blanket (CDC)

Different Forms of Clogging

14


Steady state condition of reservoir operation

• Horizontal Drainage Blanket

Pore water pressure near the toe

Fully functional drainage blanket condition (FDC)

Without drainage blanket condition (NDC)

Clogged drainage blanket condition (CDC)




• Horizontal Drainage Blanket

Excess pore water pressure contours for fully functional drain condition (FDC)

Excess pore water pressure contours for clogged drain condition (CDC) 16


Contours for CDC (a) Gradient (b) Velocity

Contours for FDC (a) Gradient (b) Velocity



• Inclined Drainage Blanket

Pore water pressure near the toe

Without drainage blanket condition (NDC)

18

Fully functional drainage blanket condition (FDC)

Contours for FDC (a) Gradient (b) Velocity

Contours for CDC (a) Gradient (b) Velocity

Clogged drainage blanket condition (CDC)


(a) Horizontal drainage (b) Inclined drainage

Pore Water Pressure Variation

Inward Outward Upward Downward Random

Inward

Random

Outward

Pore Water Pressure (PWP)

(kPa)

Horizontal drainage blanket

50 44 29.73 44 33.74 29.82

Inclined drainage blanket

34 0.50 7.99 0.58 0.61 1.57

Pore-water

pressure (kPa)

Downstream

Slope

Deformation (m)

Base Settlement

(m)

Exit Gradient

Horizontal drainage blanket (Inward Clogging)

50 0.099 0.09 2.4

Inclined drainage blanket (Inward Clogging)

34 0.08 0.07 0.95

19

(a)

(b)


Transient state condition of reservoir operation

• Drawdown : Rate 1.5 m/day

Pore water pressure at the base of the

embankment at 150th day



Excess pore water pressure for clogged drain at the end of

drawdown; i.e., on 6th day




Transient state condition of reservoir operation

• Rise-up : Rate 1.5 m/day


Pore water pressure at the base of the

embankment at 150th day Excess pore water pressure for clogged drain at the end of rise

up; i.e., on 6th day

Horizontal

drainage blanket

Inclined

drainage blanket

21



Stability values for inclined drainage blanket

NDC FDC

CDC

Stability analysis

Stability values for horizontal drainage blanket

1.241

FDC

CDC

NDC


Inclined drainage blanketHorizontal drainage blanket

Overall, no definite comparative trend could be observed from different forms of clogging

-different forms of clogging would affect the stability in their own unique way

-inward clogging is observed to yield lowest stability values

-random clogging gives highest stability


Stability analysis

Variation of

FoS for

drawdown

case

Variation of

FoS for rise up

case

Upstream faceUpstream face

Downstream face Downstream face 2407-01-2021 Short Course, NIT Warangal

25

Rate of Clogging

1 m/day

0.01 m/day

1 m/day

0.01 m/day

1 m/day

0.01 m/day

Rise up DrawdownSteady State


HYDRAULIC FRACTURING AND CRACKING OF HOMOGENEOUS

EARTHEN DAMS

Detrimental effects of cracks on earthen dams and embankments was first observed by Casagrande (1950)

Causes of different crack formation in earthen dams was summarized by Sherard (1973)

-differential settlement due to the presence of elements comprising of different deformability characteristics

-hydro mechanical forces causing redistribution of stresses in the dam during rapid filling and emptying of the reservoir

-presence of soils with piping instability placed in the body of the earth dam and in the core of earth-rock dams

-foundation comprising of compressible, or piping-unstable soils; marked changes in the topography of the footing and side

abutments of the dam

-cracking is also caused by seismic forces

Most often cracks are formed by a combination of several of the aforementioned causes.

Identify the crack locations at the end of dam construction and during its operational stage


Analysis for Case I (Sequential Dam Construction in Single and Multiple layers)

Simulation of sequential dam construction was carried out using the Load/Deformation analysis

-placing the embankment fill either in single layer or

-multiple layers

For the multiple layer analysis, the total embankment height of 15 m was divided into five smaller lifts

-the height of each lift being 3 m

27

MODEL FOR THE PRESENT STUDY

(IS 12196:1987; USBR 2003; USBR 2014; NAVFAC Design Manual 7.2, 1982, Geotechdata.info, 2013)


Analysis for Case II (Operational Stage: 2.8 m/day; Reservoir Rise Up and Drawdown Condition)

After attaining steady state condition Before attaining steady state condition28


• Possibility of hydraulic fracturing in earthen dams based on:

-differential settlement after construction

• Other pattern was the case where pore water pressure comes into play with reservoir filling

• Pore water pressure in the core increases which results in the decrease of the effective stress (σ’3)

• It becomes equal to the effective tensile strength (p’t) to jack open latent cracks.


Figure (a) : decrease in σ3 resulted in the growth of initial stress circle (I) on the left side which finally touches the failure

envelop at the circle (II) to open tension cracks

Figure (b) : initial stress circle (I) touched the failure envelope at

the circle (II) by shifting towards the left without any change in

the diameter gives a criterion in this case: σ’3 < - p’t

Ohne and Narita, 1977

during dam construction during reservoir operation


• Maximum negative stress for upstream slope of the dam simulated

-with a single lift was 29.5 kPa at a height of 17.02 m

-with multiple lift was 24.84 kPa at a height of 17. 28 m

• Maximum negative stress for downstream slope of the dam simulated

-with a single lift was 29.05 kPa at a height of 17.05 m

-with multiple lift 25.05 kPa at a height of 17. 28 m

• Maximum negative stresses occurred at height of approximately 17 m

to 17.3 m

-approximately ½ of the height of the embankment

-makes it the most vulnerable location for crack initiation

a) Upstream face

b) Downstream face

Analysis for Case I (Sequential Dam Construction in Single and Multiple layers)


31

Analysis for Case II (Operational Stage: Reservoir Rise Up Condition)

Possibility of hydraulic fracturing along the upstream face

-at around 0.2-0.25 times the embankment height measured from

the base

Possibility of hydraulic fracturing does not

exist along downstream face


Analysis for Case II (Operational Stage: Reservoir Drawdown Condition)

After the steady-state phreatic surface is attained

Upstream face

32

Downstream face

0.5-0.75 times the height earthen dam, measured

from its basePossibility of crack occurrence is minimal


Investigation for hydraulic fracturing during reservoir drawdown condition before the steady-state is

attained (a) upstream face (b) downstream face 33

• Substantial possibility of hydraulic fracturing along the upstream face

-significant release of PWP that accumulated during the reservoir rise-up

-constant reservoir level for a certain duration

-height of 9 m height from the base of the earthen dam

-approximates to 0.6 times the height of the dam measured from the base

• Along the downstream face of the dam

-no favorable conditions leading to hydraulic fracturing

-migration of phreatic surface within the earthen dam did not attain a

steady state

(a)

(b)

Before the steady-state phreatic surface is attained


• Hydraulic fracturing in dams has an inherent difficulty

-hydraulic fractures observation by direct visualization is not possible

-open only when the water pressure comes into play

-within the dam

• Dam failures due to hydraulic fracture

-development of high pore water pressure downstream of the core

• Teton Dam failure failed just within few hours after the first leakage was

spotted

• Cause of initial leak is nearly impossible as erosion would destroy any proof

• Understanding the initiation of core cracking is challenging

-numerically investigate the possibility of core cracking during different reservoir conditions by hydraulic fracturing

34

HYDRAULIC FRACTURING AND CRACK PROPAGATION IN ZONED

EARTHEN DAMS WITH A CENTRAL IMPERVIOUS CORE


c

(kPa)

φ

(degree)

γ

(kN/m3)

E

(kPa)

k

(m/s)

Shell 5 28 18 15000 10-6

Foundation 15 20 20 30000 10-10

Core 10 32 20 9000 10-8

MATERIAL PROPERTIES(IS 12196:1987; USBR 2003; USBR 2014; NAVFAC

Design Manual 7.2, 1982, Geotechdata.info, 2013)

35

MODEL GEOMETRY Earth dam models with dimensions as per IS 12169:1987


36

• Just at the initial stages of the reservoir filling

- possibility of hydraulic fracturing is substantially less

-build-up of pore-water pressure

-magnitudes of minor principal stress

-case of corresponding plots for 5th day

• Just after the completion of the reservoir rise-up

-possibility of hydraulic fracturing increases

-pore-water pressure increases

-approaches the magnitude of the minor principal

stress

-can be observed from the comparative plots of 38th

day

• After long time from the completion of reservoir rise-up

-slow dissipation of excess pore-water pressure

-very low conductivity of the material of central core

-no changes in pore-water pressure and total stress

profilesVariation of minimum total stress and PWP along the upstream

face of the central core

None of the profile indicate a conclusive occurrence of hydraulic fracturing along the upstream face of the central core


Analysis for reservoir rise-up condition (0.5 m/day)


37

• Define a modified limiting condition that can be considered for the conceptual detection of hydraulic fracturing

-the temporal variation of the stress ratio (ratio between the minimum total stress and PWP) is investigated

• As per the criterion of Ohne and Narita (1977)

-hydraulic fracturing will initiate

-stress ratio would be equal to or greater than 1 (one)

• Approximately until the 25th day, the stress ratio is transient

-development of the PWP

• From the 35th day, i.e. after the reservoir rise-up is complete

-stress ratio increases

-arrives at a stable magnitude

-stabilization of the pore-water pressure fluctuations

Variation of stress ratio with elevation for the time elapsed after

reservoir rise-up


(a) Variation of maximum stress ratio with elapsed time (b) Variation of elevation of occurrence of maximum stress ratio with elapsed time

(a)

(b)

38

• Stress ratio increases with time and attains a stable magnitude of 0.8

-considering different uncertainties associated with dam

construction

-hydraulic fracturing can be reasonably said to initiate

-stress ratio at the upstream face of the core is 0.8

• Identify the tentative location

-maximum stress ratio occurred at an elevation of 11.25 m from

the base of the dam

-approximately at 3/4th the height of the dam, measured from the

base


39

Strain contours on 38th day

Seepage velocity at Point

K along the upstream face

of the core

Hydraulic gradient contour on 38th day

Strain concentration occurred on the upstream core

face

-at about 3/4th of the height of the dam,

measured from the base

High gradients along with high seepage velocity

gives sufficient favourable conditions for internal

erosion of the dam core


• Figure (a) shows that hydraulic fracturing is possible

-only at the start of the drawdown condition

-as seen for the 5th day

• Location of maximum possibility of hydraulic fracture

-i.e., 3/4th height of earthen dam

-measured from the base

• As the drawdown progressed the pore water pressure decreased

• Figure (b) shows that hydraulic fracturing is not possible

Analysis for reservoir drawdown condition (0.5 m/day)

Hydraulic fracturing at the upstream of central core during reservoir drawdown condition (a) after attaining steady state

condition (b) before attaining steady state condition 40

(a)(b)

(a)

(b)


Non-homogenous earth fill dam

Load Transfer or Arching Phenomenon

-pore water pressure can become more than total stress

within core (Sherard 1991; Ono and Yamada 1993)

Hydraulic Fracturing

-differential settlement

-increase of pore water pressure in the core

Internal erosion

Efficacy of Drainage Blankets in Zoned

Earthen Embankment Dams

41

Ohne and Narita, 1977


Phreatic surface location

Horizontal drainage blanket (FDC) Inclined drainage blanket (FDC)

No drainage blanket condition (NDC)

42

Efficacy of Drainage Blankets in Zoned Earthen Embankment Dams


Internal gradient Seepage velocity (m/days) 43

Internal gradient and seepage velocities


44

• Internal gradient varies along the meandering seepage path

-owing to different amounts of head loss at different locations along the path

-internal gradient that might lead to the initiation of internal erosion may be as low as 0.02-0.08 for particularly

susceptible soils (Schmertmann, 2000)

-can be much lower than critical exit gradient (often considered as 1.0)

• Location of occurrence of maximum internal gradients is same for all the cases

-contact interface of the core and the downstream shell or the inclined drainage blanket

• Developed internal gradient is observed to be sufficiently high

• Combination of developed internal gradient and seepage velocities will initiate the internal erosion

-governed by many additional factors, most importantly the soil gradation

-investigation of internal erosion is out of scope of the present dissertation work

• Presence of the drainage blanket in a zoned dam having an impervious foundation

-no role in preventing the potential risk for internal erosion within the core

• Influence of drainage blankets in the case of a cracked core is investigated


Core with a crack (No drainage blanket condition)

Core with a crack (Horizontal drainage blanket ) Core with a crack (Inclined drainage blanket )

Presence of drainage blankets

-prevents the rise of the phreatic surface such that it does not intersect the downstream face

-hydraulic fracturing or cracking in the core puts the operation of the dam at risk

-presence of the drainage blanket could be effective in protecting the downstream

45

However, in reality, the crack would evolve through the central core,

rather than following a predefined path


Identification of crack propagation path

(a) Nodal points demarcating maximum stress ratio in the

region of maximum strain on the 38th day (b) Demarcated

region assigned with high permeable material to simulate virtual

flow path of water due to cracking

• Propagation path was traced by identifying the nodal points

-around the location of crack initiation

-where the stress ratio was approximately equal to 1

in the region of maximum strain contours

• Process is initiated from the 38th day

-that demarcates the possible initiation of core

cracking

• Once demarcated, a region comprising of high permeable

material was assigned in the numerical simulation

-thereby implying nearly free percolation of water

-through the region as if it is the preferred path after

the crack is virtually simulated

(a)

(b)


Simulation was completed for the 38th day

-the corresponding strain contours, gradient and

velocity were checked

-to develop the idea of successive demarcation

-the nodal points with maximum stress ratio

(approximately equal to 1) for the next day, i.e. the

39th day


• Identification of the possible crack enhancement

region on the 39th day

-as earlier, a high permeable material is

assigned

-the analyses is carried forward for the

successive days

• As the analysis is conducted progressively for

successive days,

-the path of crack propagation is identified

through the core of the dam

• Analysis is stopped once the crack propagates and

merges with the downstream face of the central

core


49

Providing a simplistic modeling technique for simulating various possible mechanisms of drainage

blanket clogging and their influence on the stress-flow-deformation response of earthen dams.

Showcasing the importance and efficacy of drainage blankets, especially the inclined chimney

drainage blankets, in establishing the continuous functioning and long-term safety of earthen dams,

even after the same gets partially clogged.

Highlighting the importance of the drainage blankets in ascertaining the performance of a zoned

earthen dam with the presence of a cracked central impervious core.

Based on numerical modeling and standard stress-PWP criterion, assessing the tentative locations of

initiation of cracking and hydraulic fracturing of the shell and core of homogeneous and zoned

earthen dams, respectively.

Tracing and identifying the path of crack propagation through the central impervious core through

recursive finite element analysis.

MAJOR CONTRIBUTIONS


Journals

1. Talukdar, P. and Dey, A. (2021) “Finite element analysis for identifying locations of cracking and hydraulic fracturing in

homogeneous earthen dams” International Journal of GeoEngineering (Springer). (Accepted)

2. Talukdar, P. and Dey, A. (2019) “Hydraulic failures of earthen dams and embankments” Innovative Infrastructure Solutions

(Springer), Vol. 4, Paper No. 42, pp. 1-20.

Book Chapters

1. Talukdar, P. and Dey, A. (2018) “Effect of Varying Geometrical Configuration of Sheet Piles on Exit Gradient and Uplift Pressure”;

In book: Geotechnical Applications Chapter: 15 Publisher: Springer, Singapore.

2. Talukdar, P. and Dey, A. (2018) “Sequential drawdown and rainwater infiltration based stability assessment of earthen dams”

Advances in Computer Methods and Geomechanics, pp 541-551.

3. Talukdar, P. and Dey, A. (2017) “Response of Earth Dams to Toe Drain Clogging” (Accepted for Book Chapter in Springer

Publications).

4. Talukdar, P. and Dey, A. (2018) “Numerical modeling of earthen dam: Validation with field data” (Accepted for Book Chapter in

Springer Publications).

5. Talukdar, P. and Dey, A. (2018) “Influence of the rate of construction on the response of embankment on PVD improved soft

ground” (Accepted for Book Chapter in Springer Publications).

50

PUBLICATIONS


Conference: National/International

1. Talukdar, P. and Dey, A. (2018) “Sequential drawdown and rainwater infiltration based stability assessment of earthen dams” International IACMAG

Symposium, Gandhinagar, India, Paper No. 236, pp. 1-11.

2. Talukdar, P. and Dey, A. (2018) “Numerical modeling of earthen dam: Validation with field data” International Conference on Infrastructure

Development (ICID), Jorhat, India.

3. Talukdar, P. and Dey, A. (2018) “Influence of the rate of construction on the response of embankment on PVD improved soft ground” Indian

Geotechnical Conference (IGC-2018), Bangalore, India, pp. 1-7

4. Talukdar, P. and Dey, A. (2017) “Response of Earth Dams to Toe Drain Clogging”, Indian Geotechnical Conference, IGC, Department of Civil

Engineering, IIT Guwahati, India, pp. 1-4.

5. Talukdar, P., Bora, R. and Dey, A. (2017) “Finite Element Based Identification of the Triggering Mechanism of a Failed Hill Slope” 15th International

Conference of International Association for Computer Methods and Advances in Geomechanics (IACMAG), Wuhan, China, pp. 1-11.

6. Talukdar, P., Bora, R. and Dey, A. (2016) “Stability analysis of ash pond dyke under static, pseudo-static and seismic conditions” 1st International

Conference on Civil Engineering for Sustainable Development – Opportunities and Challenges (CESDOC), Guwahati, India, pp. 1-6.

7. Talukdar, P., Bora, R. and Dey, A. (2016) “Forensic investigation of the failure of a marginally stable hill slope” 5th International Conference on Forensic

Geotechnical Engineering, Bangalore, India, pp. 389-400.

8. Talukdar, P. and Dey, A. (2016) “Effect of varying geometrical configuration of sheet piles on exit gradient and uplift pressure” Geotechnology Towards

Global Standards, Indian Geotechnical Conference, IGC 2016 Department of Civil Engineering, IIT Madras, India, pp. 1-4.


Relevant References

Alonso, E. E. and Pinyol, N. M., 2016. Numerical analysis of rapid drawdown: Applications in real cases. Water Science and

Engineering, 9(3): 175-183.

Das, K., Saikia, M. D, Kalita, U. C., 2017. Modelling of Embankment Breaching with Special Reference to Barak Valley, Assam.

Indian Geotechnical Conference, IGC, Department of Civil Engineering, IIT Guwahati, India, 1-4.

Foster, M. A., Fell R. and Spannagle M., 2000a. The statics of embankment dam failures and accidents, Canadian Geotechnical

Journal, 37(5), pp. 1000-1024.

Foster, M. A., Fell R. and Spannagle M., 2000b. A method for estimating the relative likelihood of failure of embankment Paper

No. 3.03a 7 dams by internal erosion and piping, Canadian Geotechnical Journal, 37(5), pp. 1025-1061.

IS 12169 (1987) Criteria for Design of Small Embankment Dams, B.I.S.

Pinyol, N. M., Alonso, E. E. and Olivella, S., 2008. Rapid drawdown in slopes and embankments, Water Resource Research, 44,

W00D03, doi:10.1029/2007WR006525.

Seed, H. B. and Duncan, J. M. 1981. The Teton Dam Failure-a Retrospective Review, 0th ICSMFE, Stockholm, Sweden, vol. 4,

214-238.

United States Bureau of Reclamation 2003. Design of Small Dams, Oxford & IBH, New Delhi.


Acknowledgment

07-01-2021 Short Course, NIT Warangal 53

Dr. Priyanka Talukdar

Research Assistant

Ryerson University, Canada

07-01-2021 Short Course, NIT Warangal 54

Thank You for Patient Hearing

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dr. arindam dey presentations... · sherard (1973) suggested that the existing closed cracks can...

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