Journal of Geological Resource and Engineering 6 (2018) 25-29 doi:10.17265/2328-2193/2018.01.004

Typology of Landslides, Investigation and Monitoring in

Flysch Deposits in Albania

Skender Allkja1, Ardita Malaj1, Luljeta Bozo2, Lorena Harizaj3, Besian Xhagolli4 and Ani Kosho5

1. ALTEA & Geostudio 2000company, Tirana 1000, Albania

2. Department of Geotechnical Engineering, Polis University, Tirana 1000, Albania

3. ALTEA & Geostudio 2000company, Tirana 1000, Albania

4. ALTEA & Geostudio 2000company, Tirana 1000, Albania

5. Devoll Hydropower company,Tirana 1000, Albania

Abstract: The development of infrastructure, energy and tourism in recent years in Albania has brought the necessity of geotechnical studies to a higher technical level. Most of these buildings (hydropower, motorway, pipeline) are built in mountainous areas with complicated geological conditions. The most complicated obstacles seem to be huge landslides, especially for those situated on flysch deposits. Most of the huge landslides were innate and active by the end of Pleistocene; however, some of them, especially those in flysch areas, are activated due to recent changes of climate and intensive man activities. Examples of re-activation of old landslides are encountered on Qukes-Qafe Plloçe road, on Devoll river valley which are being built several hydropower and on Poliçan-Potom area where a gas line is built. These landslides are under design investigations using field and laboratory methods like drilling, inclinometers and piezometers measurement, geophysical probing, rock and soil testing. All slopes with flysch rocks in Albania have low stability because of the presence of active landslides. In any case they should be studied using advanced geotechnical methods and monitored for long time in order to take the right protective measures. Key words: Inclinometers, landslide, monitoring, mudstone, sandstone.

1. Introduction

The valleys (of Devolli & Osumi) mentioned in this

paper are located in the central part of Albania. They

cross the counrty from east to west.

Due to the numerous, important, engineering

projects, such as: roads, hydro-electrical power stations

and an international gas pipeline, various detailed

geological and geotechnical studies, have been

undertaken, for these regions.

The region of Devolli & Osumi valley, is composed

of flysch rock, from the top, down to the bottom of the

valleys. The flysch rock mass is characterized by

lithological heterogeneity, due to the frequent vertical

and lateral alternation of the different lithological

sequences.

Corresponding author: Skender Allkja, M.Sc., research

field: geotechnical hazards.

These valleys have developed from the

ever-changing physical & geological, phenomena.

The hydropower stations, roads, pipelines that are

built as well as any future project that will be built in

this region, are threatened by different landslides that

are present, active or about to become active.

This paper will describe and discuss case studies of

landslide occurrences, the geotechnical properties of

the materials of which the slope are composed of, as

well as the analyses and the remedial works undertaken

and necessary to stop the sliding.

2. Geotechnical Properties of the Landslides in Devolli River & Osumi River Valley

In order to determine the geological setting, the

landslide dimensions and the position of the slip

surface, geotechnical investigation and works were

performed [1-4].

D DAVID PUBLISHING

26

For all ri

and borehol

down to b

undisturbed

BH, inclinom

order to mo

time and la

characteriza

present in ea

3. GeologiSlopes at D

The valley

shape valley

covered with

also big are

vegetation. T

number of h

destroyed b

transformed

and exhibit

distinct and

phenomena

weathering;

and of the

landslides.

The follow

(1) Depos

They are

and Sandsto

medium to w

is weathered

(2) Depos

They are

They have b

cementation

Generally, th

(3) Holoc

Due to th

divided into

deposits.

Typology

sked or activ

le investigati

edrock form

samples were

meters and p

onitor the mo

aboratory te

tion of the

ach of the stu

ical SettingDevolli & O

ys of Devolli

ys, with very

h bushes and

eas of the sl

The outcrop o

ouses were bu

by the slope

into agricultu

clearly visibl

d visible ge

observed in

collapse and

core format

wing deposits

sits of Palaeog

flysch depo

one. They h

weak cementa

d. Generally,

sits on Neoce

composed o

brown to be

n and their s

hey form uns

ene Deposits

he formation

alluvial ones

of Landslide

ve areas, geo

ion was con

mation, where

e taken. In the

piezometers w

ovement for

sts were co

geological l

udied landslid

g & MorphoOsumi Vall

i and Osumi,

y steep slopes

d high woodla

lopes, which

of the landslid

uilt there, som

movements.

ural lands. Th

le bumps and

eological an

these valley

d slide of the

tion; tectonic

s, are found in

gene (Pg22; P

osits, compos

have brown

ation and thei

they form un

ne (N1; N3)

of Mudstone

eige colour, m

superficial pa

stable slopes.

s

n process, th

s, torrent one

s, Investigati

ological mapp

nducted, reach

e disturbed

e aforementio

were installed

a long perio

onducted for

layers that w

des [2].

ogenesis of leys

are “U” and

s. The slopes

and, but there

h are stripped

de is visible a

me of which w

The slopes

hey are defor

d holes. The m

nd geodynam

ys, are: Eros

e covering st

c faults and

n this region:

Pg31; Pg3

2; Pg

sed of Muds

to beige col

ir superficial

nstable slopes

e and Sandst

medium to w

art is weathe

hese deposits

es and colluvi

ion and Moni

ping

hing

and

oned

d, in

d of

the

were

f the

“V”

s are

e are

d of

and a

were

are

rmed

most

mical

sion;

trata

old

:

33)

tone

lour,

part

.

tone.

weak

ered.

are

iums

4. TVa

Fig.dip the

Fig.dip slop

Fig.resu

toring in Flys

Typical Lanalley

. 1 Landslideangle of the rovalley.

. 2 Landslideangle of the ro

pe of the valley

. 3 Landslideult of river ero

sch Deposits

ndslides in

s covered by coock layers, is in

s covered by coock layers is in y.

es activated by sion.

in Albania

Devoll’s an

olluvium depon the direction

olluvium depothe opposite d

imbalances of

nd Osum’s

osits, where theof the slope of

osits, where thedirection of the

f the slope as a

s

e f

e e

a

Fig. 4 Landstrong and we

Fig. 5 Landduring road c

5. LandslOsum’s V

During th

in previousl

material w

weathering a

hypsometric

bottom of th

Due to the

the consequ

energy of th

cover strata

resulted in

shear strengt

These lan

Typology

dslides activateeak rock.

dslides created construction or

lide DescrValley

he morpholog

ly formed d

as formed

and waspartly

cally higher

he slopes.

e different ero

uence of var

he relieve, th

a are litholo

different filt

th on the slop

ndslides were

of Landslide

d at the tecton

by big unsuppr other objects

ription in

gical evolution

depressions,

by physical

y brought by

parts of the

osion intensity

iable climate

he colluvium

ogicaly hete

tration system

pes.

e of multiple

s, Investigati

nic contact betw

ported excavats.

Devoll’s a

n of these slo

the accumul

l and chem

gravitation, f

e slopes, to

y, that resulte

e conditions

m deposits of

rogeneous. T

ms and diffe

regression ty

ion and Moni

ween

tions,

and

opes,

lated

mical

from

the

ed as

and

f the

That

erent

ypes

and

to t

slop

of

Geo

repo

(see

6. the

T

mov

The

vall

in d

6.1

A

road

vall

T

dur

som

Fro

labo

mea

F

land

T

rese

targ

crea

rese

eva

thes

mov

add

N

stab

mas

alon

toring in Flys

d the sliding p

the top of the

pes. These lan

these paper

ostudio 2000,

orts prepared

e Figures from

Results of e Valley of D

These landsl

vement, with

e target of ea

ley of Devoll

detail separate

The Results o

As was descri

ds, were desi

ley.

The landslide

ing the constr

me existent o

m the test re

oratory, the

asures, which

From the 2-ye

dslides have b

The landslide

ervoirs have

get in these la

ated by move

ervoir. The l

aluated and pr

se measures i

vement, extr

dition to the c

No remedial

bilization of t

ss that may

ng with the re

sch Deposits

process devel

e slopes, caus

ndslides were

rs for sever

, 2009-2016.

d for Devolli

m 1 to 5).

the LandsDevoll

lides are stu

respect to tim

ach study in t

and Osum, is

ely, below.

of Devoll’s V

ibed above, t

igned and bu

s at road axis

ruction of the

old landslides

sults conduct

ere have b

h have been e

ear monitorin

been stabilize

es located n

big dimensio

andslide areas

ement of big s

landslide haz

rotective mea

include long-

ra protective

alculations m

l works ar

these landslid

slide into th

eleased energ

in Albania

loped from th

sing further s

e researched b

ral years (A

Miscellaneou

valley and O

slides Case-

udied in th

me and weath

the landslide

s different and

Valley Landsli

two large dam

uilt in the afo

s, resulted by

e road and the

s, with small

ted in the fie

been taken

effective.

g period and

ed.

near the larg

ons (Figs. 6

s is to evalua

soil masses, d

zards, near th

asures are tak

-time monitor

measures ar

made.

re undertak

des, but the p

he reservoir

gy and the imp

27

he bottom, up

liding on the

by the authors

A.L.T.E.A &

us geological

Osumi valley)

-Studies in

eir dynamic

her conditions

areas, in the

d is described

ide Case

ms and some

orementioned

y excavations

ere were also

dimensions.

eld and in the

engineering

results, these

ge dams and

and 7). The

ate the hazard

directly in the

he dams, are

en. Although

ring, for each

re needed, in

en for the

potential soil

is estimated,

pact that they

7

p

e

s

&

l

)

n

c

s.

e

d

e

d

s

o

.

e

g

e

d

e

d

e

e

h

h

n

e

l

,

y

28

will have on

calculated la

height of the

lake. These

dynamic mo

conditions.

Monitorin

level change

6.2 The Resu

As was d

gas pipeline

The lands

during the c

some existe

From the tes

laboratory,

have been ef

From the

landslides ha

Fig. 6 Lands

Fig. 7 Lands

Typology

n the water

ater on, durin

e dam, over th

e landslides

ovement with

ng has given

es occur, they

ults of Osum’

escribed abov

and some ac

slides at road

construction o

nt old landsl

st results con

there have b

ffective.

e 1-year mon

ave been stab

slide at Banja

slide at Moglic

of Landslide

level of the

g the design p

he maximal w

are being s

h respect to t

good results,

y will be studi

’s Valley Lan

ve, in the Os

ccess roads ar

d axis, resulte

of the road a

lides, with sm

nducted in the

been taken m

nitoring perio

bilized.

dam.

ca dam.

s, Investigati

lake and th

phase, as a sa

water quota in

studied for t

time and wea

, but if any w

ied thoroughl

dslide Case

sum’s valley,

re built (Fig. 9

ed by excavat

and there are

mall dimensi

e field and in

measures, w

od results, th

ion and Moni

is is

afety

n the

their

ather

water

ly.

one

9).

tions

also

ions.

n the

which

hese

Fig.mea

Fig.

T

dim

are

mov

spe

solu

(

(b

eng

the

toring in Flys

. 8 Cumasurement at M

. 9 Landslide

The landslide

mensions. The

monitored f

vement has

cified by the

utions:

a) a non-exis

b) the lands

gineering mea

critical area.

sch Deposits

mulative displMoglica dam.

at Potom area

es located ne

ese landslides

for two years

been found

e designer, t

tent sliding a

lide size is

asures are tak

in Albania

lacement of

a, Osumi valley

ear the pipeli

s are studied

s. In the area

to exceed t

there exist t

area is require

evaluated an

ken for the sta

inclinometer

y.

ine have big

in detail and

as where the

the tolerance

two types of

ed.

nd protective

abilization of

r

g

d

e

e

f

e

f

Fig. 10 measurement

In case (b

order to de

protective m

7. Conclus

By the com

that have b

valley, there

Typology

Cumulative t at Potom land

b), permanent

etect any new

measures also

sions

mplex geolog

been conduct

e have been

of Landslide

displacement dslide area.

t monitoring w

w movemen

will be appli

gical and geo

ted in Devol

found certain

s, Investigati

of inclinom

will be neede

nt and additi

ed (Fig. 10).

technical stud

ll’s and Osu

n types of fly

ion and Moni

meter

ed in

onal

dies,

um’s

ysch

rock

T

dan

to b

slid

eng

prev

It

be

geo

T

or n

dur

effe

[4].

Ac

T

effo

from

Re

[1]

[2]

[3]

[4]

toring in Flys

k landslides,

The movemen

ngerous for th

be built, there

des, the dyna

gineering and

vent or elimin

t is recomme

built in the

otechnical stu

The areas with

new landslide

ing and after

ectiveness of

knowledge

The work pre

ort between t

m “A.L.T.E.A

ferences

A.L.T.E.A &Reports PrepA.L.T.E.A &Reports PrepF. G. Bell ImGeological HMitigations.T. Takahashi Debris Flow M

sch Deposits

varying from

nt of these m

he existing fac

efore it is imp

amic of their

d monitoring

nate the slidin

nded that for

ese areas, a

dy should be

h low stabilit

es might be a

r constructio

f the protecti

ements

esented here r

the authors a

A & Geostudi

& Geostudio 2ared for Devoll

& Geostudio 2ared for Osumimprint of the THazards Their

Imprint of the TMechanics, Pre

in Albania

m a small to a

masses of ro

cilities, or the

portant to cha

movement,

measures, th

ng hazards.

r any new fac

detailed geo

carried out [

ty and the on

ctive, are to b

on, in order t

ive engineeri

represents a

and numerou

io 2000” Com

2000, 2009-20li valley. 2000, 2009-20i valley. Taylor & Franc

Assessment, A

Taylor & Francedictions and Co

29

large scale.

ocky soils, is

ones that are

aracterize the

the effective

hat will limit,

ility that will

ological and

3].

nes where old

be monitored

to verify the

ing measures

collaborative

us colleagues

mpany [1, 2].

16. Geological

16. Geological

cis group 2006.Avoidance and

cis Group 2007.ountermeasures

9

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