Rock Classification (2) (1)

7/25/2019 Rock Classification (2) (1)

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Report

on

Geo-technical

Investigation

of

I{ight

Bank

Abutrnent

Slope

of

the

l(ali

Gandaki

Bridge

along

Ridi

--

GalyangRoad

Sr-rbnritteci

to:

f;ovcntntcn1

0l'Nepal

h.'[

i

nistr'.1

o1-

Pir-r,sicaI

Irrll'astntctltre

&'l'ransport

I)cparlnrcnl

o I Roads

\\/cstcrn

[iegional

Roads

Directolate

I)ivision

l{oacls

Office

Palpa

Submitted

by:

Prestigc

Consulting

(P.) I-td.

A

n

a n'r

na

gar,

1(

athrn

a

ncltl

Pl-ionc:

4416054

2012113



Acknowledgements

\\ie

lvorrlcl

Iil<c

to cxllrcss

our

sincerc

gratitLrde

to Dcparttlletrt

of

Roecls,

Divisiorl

Roads

O{1ice'

irirlPa

lbr'Plovicii,,g

Lis the

oppoltLrnitv

to

carry

o[tt

the

presenl-]ob.

We

l'oLIld

also

lilic

to

thatrli

l:r..

i(.

Ranubhat.

tlte Division

Chief

tbr

his

valLrable

sLtppoIt.

suggcstions

atrcl

cot.lttrtcrrts

cltttltrr

tlrc

coursc

ol

thc

srLrclr,.

N,l'oreover.

thanl<s

also

go to

llr.

I(cshav

0.iha,

Ilrrgirlccr.

DRO

Palpa

lilr

ir

is

lirrrl eoollcr.li{ion

artcl

sLtppotl.

Llrst

SLrl

uttt

thc

lcast.

rve woulcl

lrlic

to

cxptcss

ortt'siltect"c

lrllIrcciltit'tl

lttrcl

grirtitLrclc

ttl

cnsinccr.s

anrl

thc sial'f'of'the

DRO.

[,alpa

lbr

their

l<inr]

help

ancl

Iogistic

stlpllort.

lt

is

orlli'tt'iLh

rlr.:rr.,

111r,,,'t

o1'all

cottcerrlccl

that

the

prtscirt

stirdy

coLr

lcl be

comllietccl'

(

Pral<a-sh

C

itirrttlra

(ihirrlirc)

Scnior

Cicologisl

Prcstigc

Coristrlting

(.P) t,ttl.

Anantnagar.

Kathtllancltt



1.0 lntroductiorr

The

geotechnical investigation

I

study

of

motorable

bridge

over

Kaligandaki

river

along

Ridi

-

Glyang

road

of Gumi-syanja

district

has been

carried

out

for

Division

Road

Office,Palpa'The

bridge

is

under

construction.

The main objectives

of present

study were:

.

Geological/Geoteclrnical

assessment

of

bridge

site

.

Failure

Assessment

of

rock

slope

cut

at

bridge

axis

.

Rocl<mass

Classification

of

bridge

site

2.0 Methodology

.

Thc tearn.

has

drscussed

with

personals

of

Bridge

project,

DoR

and

DRO

Palpa

to

know

problcm

of construction

site.

Then

present stucly

was

divided

into

two

stages:

n

Ficld

study

(Site

Visit

for

data

collection)

.

Office study

(Data processing,

analysis

and

report

preparation)

In

freid stuciy

geoiogicai

study

was

carricd

by

geological

travei'se

along

i'oad

corridor

and

rivcr

banl<

of

l(aligandaki

River

at

vicinity of

bridge

construction

site'

Main

rocl<

type

and

cliscontir'tuities

type were

identified

during

field

study'

The

oricntations

of

discontinuities

were

measured

along

cut

slope

of

road

corridor

and

river

bank.

A

scan

line survey

and

window

survey

was

carried

out

for

discontinuity

mapping

to

assess

stability

scenario

of

bridge

foundation

and

cut

slope. The rock

mass

classification

was

carriecl

by Geomechanics

Classification(

Bieniawasl<i's

Rock

Mass

Rating

System)

to

assess

rocl< mass

class

of,bridge

site.

I

tl

3,0 Site

Geology

The bridge

site

lids at

the

lesser

Himalayan

Zone

of

Western

Nepal.

The

major

rock

types

of

.t

bldge srte

are

grey-dark

grey

colored

,

fine-medium

grained,

foliated

and

closely

-u"'d

closely

spaced,moderately

-slightly

weathered

Phyllite

bed

rock

with

interbedding

of

Dolorrite/euartzite.The

bridge

axis

lies at

steep

rock

slope.

The

rocl<

exposure

at Ridi

side

is

highly

weathered

and

sheared.

Series

of

ahare

zones

have

been

observed

at

the

road

cut

slope.

Ground

water

seepage

and

flow

is

frequent.

zl.0

Discontinuity

Survey

Discor-rtinuity

Survey

was

carried

along

road

corridor

and

river

banl<'

The

changes

in

orientatlon

of discontinuity

has been

noticed

and

recorded

at

chainagewise

measurement

frorn Rudrabeni

sicle

to

Ridi

side.

The

starting

point

of scanline

survey

is at

the

ending

of

recent cutslope

towards

Rudrabeni

side and

ended

at

Ridi

Side

upto

recent

cut

slope.The

chainagewise

description of discontinuity

is

given

below:



iable:i

Bearing

FP44Ol74

A.B

(llLrdrabcni

Side

at

ending

of

recent

cut

slope)

JP=r30176

lP=341112

JP=344116

Slope=135/60-

70

FP=000/59

)P=1-21,166

)P=3L0149

Slope=135/60-

7A

3ss/BB

J

P=080/65

)P=33ol2B

JP=O35147

Slope=1-35/60-

70

tP=o40143

Station

Attitude

of

Discontinuities

Geological

description

tlW,Fr, PhYllite

bedrock

with

interbedding

of

Qu

a

rtzite/Do

lo

rn

ite



I

I

t-

l

I

t_,

)P=265183

Stream

at

Uphill

side

i P=355/34

JP=25Ol40

JP=04O134

JP=13017

4

J

P=055/55

FP=040154

JP=295125

JP=o55/42

lP=12O172

JP=215145

JP=795/55

JP=1"02172

JP=260185

JP=35O17O

Slope=130170

FP=355/60

JP=1,LO/BZ

JP=0L5148

lP=305/80



JP=O95/lA

Aperture=6m

m-l-

cm

Aperture=1-

1.5 cm

Ap

e

rtu re=2

5r

m

Seepage

at

F

Aperture=1c

m-30mm.

)P=110163

J

P=335/65

Slope=130/70

FP=340/37

JP=330/78

JP=170162

)P=340146

)P=265185

JP=L6O/65

FP45A/62

JP=1-7Ol58

J

P=110/65

F

P=350165

JP=265/67

FP=350130

J

P=001/82

JP=L25l70

FP=350/70

JP=170/45

Stream

r,rplrii



i

L

I

I

L

I

l

I

I

.lP=0BB/82

Slope=150/60-

1.3o17O

c-ll

)150

o-)

F=350145

J P=145/50

Slope=130-

$a160-70

llW,Fr,Phyllite

bedrock

wlth

intercalation

of

Qu

a

rtzite/Dolom

ite

Share

Zone,Water

scepaSe

zonc

il-l

(At

RidiSide

Lr;r

to

recent

cut)

1600

100

F=350/67

tP=13A/76

JP=355/65

tP=265185

tP=o92/45

Slope=092/50

llW,Fr,Phyllite

bedrocl<',ryrih

intercalation of

Quartzite/Dolomite

Share

Zonc,Water

seepage

zone

Rive r

Banl<

FP=34A/37

Bridge

axis

at

River

Uanl<

)P=350147 SW-MW,

Fr, Phyllite

bedrock

with

intercalation

of

Quartzitc/Doiom

ite

JP=045/28

JP=135/75

JP=170/52

)P=255/30



SIope=3.20l70

Source:

Field

Measurement

5.0

Rock Mass

Class

I

hc

rocl<mass

of bridge

site

is

almost

soft

rock,i.e.

flne

grained,

moderately-highly

weathered,fractured and

jointed,shared

Phyllite bedrock.

However

some

interbedding

and

intercalation

of

medium

grained,slightly

weatlrered,

thinly

bedded

Quartzite/Dolonrite

ltcclrocl< has also

becn

observed.

The

proportion

of

hard

and

soft

rocl<

is

estimatcd

on the

basis of

rnanual linear

measLlrement

of

road

length and

slope

cut

lcngtlr.

Ihc

Roclcrnass CIass

was categorized

by

Geomechanics

Classification(

Bieniawasl<i's

flocl<

Mass

Rating System).

The chainagewise

description of

rocl<mass

class

atrd

cstlmatcd

proportion

of

hard

and

soft

rocl< is

given

below:

Table:2

Station

Distance,m

Rock

Mass

Class

A-B

(ttudrabeni

Side

at ending

of

recent cut

slope)

6.6

lV(

Poor

Rock)

B-C

20

lV(

Poor

Rock)

C-D

50

lV( Poor

Rock)

D-E

1U.

/U

lV( Poor

Rock)

E-F

J:)

lV(

Poor

Rock)

F-G

71

lV(

Poor

Rock)

G-H

6L

V(Very

Poor)

H-t

100

V(

Very Poor)



(At

Ridi

Side

up

to

recerri

cut)

At River

Bank

223

lll-(Fair

Rock)

Source:

Manual

Measurement

of

Linear Distance

at

field

study

I

he

chainagetruise

description

of

cstimate

d

proportiorr

of

hard

and

soft

rocl<

is

given below:

Ta b

lc:3

Stati on

A-B

(RrrclrabeniSide

at

e

nding

of

reccnt

cut

slope)

il-,--

C-D

NI:

fC

L-l

Distance,m

Rock

Mass

Class

Percentage

of

Hard

Rock

and

Soft

Rock

6.6

L=6.6m.

Il=20

n-i.

Area=132m2

Hard

llock=26.4rm2

Soft

Rocl<=105.6

m2

2A

L=20m.

H=20

m.

Area=400m2

Hard

[]ocl<=S0rr2

Soft

Rocl<=320

m2

50

L=50

m.

ll=20

m.

I

t

Are

a=1000m2

Hard

Rocl<=200m2

Soft

Rocl<=800

nr2

10.70

L=l-0.7

m.

H=20

m.

Area=2L4m2

llard

Rock=

42.8

mZ

Soft

Rock=

17

r.2 mz

5J

L=33

m.

H=2.0

m.

Area=660m2

Hard

Soft

Rocl<=132-

m2

Rock=S28

m2



21

L=21

nr.

ll=20

m.

Area=420

m2

Ilard

[locl<=84

rl2

Soft

Rocl<=336

rlr2

G-il

B2

L=82

m.

H=20

m.

Area=1640

m2

Hard

Rock=328

m2

Soft

Rocl<=l-312

m2

H-l

lAt

Ridi

side

up

to

rccent

cut)

100

L=100

m.

H=20

nr.

Area=2000

m2

l-lard

Rocl<=200

m'

Soft

Rock=1800

m2

At

[1ivcr

Banl<

1L)

L=223

m.

*H=15

m.

Area=3345

m2

llaro

l(ocK=oov

Ill

Soft

Rocl<=2

67

6

m2

*5loP

to bc

cut

for

brldgc

foundation

lcvcl

Note:

Cut

slope

H"igf,t

i,

*ti*ut"d

according

to

DRO

Official

information

6.0

FailUre

Assessment

I

Failure

assessrrent

was

carried

out

atthe

road

cut

slope

and

river

banl<

slope

along

bridge

axis

by

kipcmatic

analysis.

Stereographic

projection

of

discontinuity

data

has

been

carried

out.l-hc

ticscrlption

of

Failure

assessment

is

given

below:

i

Ta

ble:4

Atl

(Ruclrab

al

e

irdin

rece

r-it

c

slopc)

ta

ticn

Beari

ng

Distance,m

Attitude

of

Discontinuities

Failure

eni Side

gof

rut

3

100

6.6

34O/24



I

l

i

j

I

t---

l

I

l

I

I

t_

I

20Bo

JP=1.30116

)P=347172

lP=344116

Slope=135/60-

70

FP=000/59

JP=3rol49

Slope=L35/6O-

70

F

P=355/BB

J P=08C/65

JP=330128

)P=o35141

Slope=135/60-

70

FP=a4ol

43

)P=265183

)P=355134

FP=355110

Lateralwedge

failure(029

140,03413

)P=13o174

I

t_-

I

I

I

I

I

I

i



J

P=055/55

FP=04a154

JP=295125

JP=055/47

)P=L20112

tP--27514':

)P=295155

JP=LO2172

JP=260185

)P45A170

Slope=

130/70

Bridge

Axis

at

Road

F

P=355/60

JP=.tL0lBZ

i

P=305/80

JP=095170

)P=17O163

PIanc

['aiure(DAll)\

Cer-rtral

wedgc

failure(102/32)

Lateral

wedge

failurc(203

116,19210

4)

I

I

I

l-



Ce

niral

wed6lc

fail

u rc(143/60),

I arcr'

al

wedge

f a

ilu

re(0BB/r6)

t--

I

Stablc

[.']o

Failure

t___

1

I

i

i--

I

L

i

J P=335/65

Bridge

Axis

at

Road

Slope=130/70

FP=34ol3l

)P=330178

)P=170162

)P=340146

JP=265185

Sta

b

lc

No

Failurc

J

P=160/65

tP=350162

P

I

a

n

e

F

ai

I u

r

e(77

l)

I

i;2\

Central

Wedge

F

a

ilLrrc(154/56)

)P=\7Ol58

J

P=L

10/65

FP=350/65

)P=265161

FP=350/30

JP=00L182

JP=125170

Stable

No

Failure

Slope=150/60

FP=35o110



G-11

Side

up

nt

cut)

ll i

'.re

r

llank

I

I

Lateral

Wedge

Failure\172145)

Slo

pe=150/60-

r3o110

F=350145

J

P=145/50

Slope=130-

1so/60-70

F

=3501

67

lP=L30l76

I

P=355/65

J

P=265/85

)P=O92145

Slop

e=092/60

Bridge

axis

at

River

Bank

I

I

FP=34O/37

JP=35O/47

lP=045128

)P=1,35175

)P=]70152

JP=255130

Slope=L7A/70

Central

Wedge

Failure

(096/19)

LateralWcdgc

Failure(049

ILa,050IL



2,055/15

)

--i

I

I

Overall

view

of

bridge

site



r

'l'

i

:,,1-

,

:::.

,,:l

View

of

bridge site

:,

l



Close view of share

zone



$:r"::

.$ini

,iiii

:]

.Jitiji

i,:l:.:,:

i.{,1

i

,1, idEi,i

.iri

ri,.ll

ii.irl,i,,

:.i::iii;lr:"i1i;r1.l

:1

:..

.:::.

*i$ffi

:.'

:.1rii

Close

view

of

Bridge

axis

i+*i-'-18 t:.

;ti

Rock Classification (2) (1)

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Transcript of Rock Classification (2) (1)