modulus of deformation of rock masses

8/13/2019 Modulus of Deformation of Rock Masses

http://slidepdf.com/reader/full/modulus-of-deformation-of-rock-masses 1/24

CORRELATION OF IN-SITU MODULUS OF

DEFORMATION DETERMINED BY DILATOMETEROR GOODMAN JACK WITH THE DEGREE OFWEATHERING OF ROCK MASSESAND ROCK MASS RATING RMR)

Bo-An Jang and Hyoyeol Kim

Division of Earth Sciences,Kangwon National University, Korea



Introduction - Plate Loading Test

Modulus of deformation Modulus of elasticity

reue

Displacement



Modulus of Elasticity

Property of intact rock

Usually measured from specimen

Lab tests - uniaxial compression test In situ test – plate loading test, dilatometer test

Modulus of Deformation

Property of rock mass

Measured in situ test -plate loading test, dilatometer test

An important parameter for design of geotechnical

structure



Background

Modulus of deformation is often predicted by RMR

Several relations between modulus of deformation and RMR

are suggested

0 20 40 60 80 100

0

20

40

60

80

E

M

( G P a )

RMR

100RMR 2EM Bieniawski(1978) :

40

10RMR

M 10E

RMR)Exp(0.070.03Dmd

Serafim & Pereira(1983) :

Kim (1993) :



Motivations and Objectives

Modulus of deformations in other researches were

measured by plate loading test.

The numbers of data in other researches are small. Modulus of deformation measured by dilatometer may be

2 – 3 times lower than those measured by plate loading

test (Rocha, 1974).

Correlation of in-situ modulus of deformation with degreeof weathering.

Correlation of in-situ modulus of deformation with RMR.



Data collection

2354 data of Modulus of Deformation

were collected.

Kangwon : 870

Kyonggi(with Seoul, Incheon ) : 613

Kyeongbuk(with Daegu) : 274

Kyeongnam(with Busan, Ulsan) : 172

Chungnam(with Daejeon) : 128

Chungbuk : 102

Jeonbuk : 163Jeonnam(with Gwangju) : 22

Cheju : 10



Correlation of in-situ modulus of deformationwith degree of weathering

Highly weathered rock Moderately weathered rock

-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0

0.000

0.013

0.025

0.038

0.050

0.063

0.075

0.087

R e l a t i v e F r e q u n c y

log EM

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4


log EM




Slightly weathered rock Fresh rock

-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0

0.000

0.013

0.025

0.038

0.050

0.063

0.075

0.087

-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4


log EM

-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07


log EM




-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

M = 5.75 GPa

= log 100.37

M = 2.24 GPa

= log 100.34

M = 0.96 GPa

= log 100.37

N o r

m a l i z e d F r e q u n c y

3.72 GPa1.38 GPa0.43 GPa

M = 0.20 GPa

= log 100.37

SW

MW FR HW

log EM



Correlation of In-situ modulus of deformationwith degree of weathering

-2 -1 0 1 2

0.0

0.2

0.4

0.6

0.8

1.0

16.6 GPa3.721.380.430.07

10%

50%

90%

FR SWMWHW

FR

SW

MW HW

C R F

log EM



Correlation of In-situ modulus of deformationwith degree of weathering

Degree of weatheringIn-situ modulus of

deformation(GPa)

Highly weathered rock 0.07 ~ 0.43

Moderately weathered rock 0.43 ~ 1.38

Slightly weathered rock 1.38 ~ 3.72

Fresh rock 3.72 ~ 16.6



Relation between in situ modulus ofdeformation and RMR

0 20 40 60 80 100

0

20

40

60

80

E

M

( G P a )

RMR

Upper 5%

Lower 5% n = 875



Relation between in situ modulus ofdeformation and RMR

0 20 40 60 80 100

0

20

40

60

80

E

M

( G P a )

RMR

Equation suggested by this research

50

16RMR

10EM

n = 786

R = 64.0%



0 20 40 60 80 100

0

20

40

60

80

E

M

( G P a )

RMR

Bieniawski(1978)

Serafim & Pereira(1983)

Kim(1993) This research

Comparison of suggested equations 1)



Comparison of suggested equations 2)

0 20 40 60 80 100

0

20

40

60

80

E

M

( G P a )

RMR

Serafim & Pereira(1983)

2.5 * This research

3.0 * This research

Serafim & Pereira vs this research



Relation between modulus of deformation andRMR for gneiss

0 20 40 60 80 100

0.01

0.1

1

10

100

Gneiss ; n=420

E M

( G P a )

RMR

EM

=100.019*RMR-0.314

R=0.63

EM

=10(RMR-16)/50



Relation between modulus of deformation andRMR for granite

0 20 40 60 80 100

0.01

0.1

1

10

100

Granite ; n=75

EM

=100.019*RMR-0.459

R=0.73

E

M

( G P a )

RMR

EM

=10(RMR-16)/50



Relation between modulus of deformation andRMR for sandstone

0 20 40 60 80 100

0.01

0.1

1

10

100

Sandstone ; n=66

EM

=100.014*RMR-0.139

R=0.57

E

M

( G P a )

RMR

EM

=10(RMR-16)/50



Relation between modulus of deformation andRMR for shale

0 20 40 60 80 100

0.01

0.1

1

10

100

Shale ; n=26

E

M

( G P a )

RMR

EM

=100.021*RMR-0.597

R=0.68

EM

=10(RMR-16)/50



Relation between modulus of deformation andRMR for Limestone

0 20 40 60 80 100

0.01

0.1

1

10

100

limestone ; n=20

E M

( G P a )

RMR

EM

=100.015*RMR-0.069

R=0.67

EM

=10(RMR-16)/50



Relation between modulus of deformation andRMR for other rock type

0 20 40 60 80 100

0.01

0.1

1

10

100

Others ; n=179

E M

( G P a )

RMR

EM

=100.019*RMR-0.339

R=0.66

EM

=10(RMR-16)/50



RMR values predicted by relationssuggested by this research and others.

RMR

Bieniawski(1978)Serafim &

Pereira(1983)Kim(1993) This research

Moderately

weathered Rock50 ~ 51 0 ~ 16 37 ~ 55 0 ~ 23

Fresh Rock 52 ~ 58 33 ~ 59 69 ~ 90 44 ~ 77

• Moderately weathered Rock : EM = 0.43 ~ 1.38 (GPa)

• Fresh Rock : EM = 3.72 ~ 16.6 (GPa)



Conclusions

In-situ modulus of deformation of rock masses were correlated

with the degree of weathering.

Modulus of deformations show almost the same normal distributions in

each degrees of weathering. The ranges of in situ modulus of deformation for each degree of

weathering are as follows.

completely weathered rocks : 0.07 - 0.43 GPa

moderately weathered rocks : 0.43 - 1.38 GPa

slightly weathered rocks : 1.38 - 3.72 GPa

fresh rocks : 3.72 - 16.6 GPa



Conclusions

In situ modulus of deformation were correlated with RMR and

new equation is suggested :

EM = 10(RMR-16) / 50

New equation suggested by this research gives more reasonablevalues than others.

In situ modulus of deformation measured by the dilatometer testor Goodman jack test is 2.5 - 3 times lower than that measured bythe plate loading test, which is agreeable with the results obtainedby Rocha(1974).

Although small differences of relations with respect to lithologywere found, the equation suggested by this research could be usedto predict in situ modulus of deformation from RMR values for allrock types.

modulus of deformation of rock masses

Documents