1. Advanced Geotechnical Engineering
Laboratory and in-situ
rock testing
Advanced Geotechnical Engineering
EAG 442
By: Dr Mohd Ashraf Mohamad Ismail

2. Table of content
Laboratory test
Simple index test
In-situ test

3. Table of content
Laboratory test
Simple index test
In-situ test

4. Density Porosity Permeability Strength Durability Sonic velocity
Index properties
Density
Porosity
Permeability
Strength
Durability
Sonic velocity

5. Density Porosity Permeability Strength Durability Sonic velocity
Index properties
Density
Porosity
Permeability
Strength
Durability
Sonic velocity

6. Uniaxial compressive test (UCS) Universal testing machine (UTM)
Laboratory test
Uniaxial compressive test (UCS)
Load
Before failure
Universal testing machine (UTM)
Determination of the Uniaxial compressive strength of cylindrical intact rock specimens (load up 2000kN). The load rate is kept constant using a servo-hydraulic control unit.
After failure

7. Uniaxial compressive test (UCS)
Laboratory test
Uniaxial compressive test (UCS)
Basically, there are four main factors which control the test results other than the intact rock properties itself.
Friction between platen and the end surface
Specimen geometry (shape, height to diameter ratio and size)
Rate of loading
Water content
A height to diameter ratio of 2 (54 mm in diameter and 108 mm in height) had been employed and testing procedure will strictly follow the Suggested Methods for Determining the Uniaxial Compressive Strength and Deformability of Rock Materials (ISRM, 1981).

8. Uniaxial compressive test (UCS)
Laboratory test
Uniaxial compressive test (UCS)
Rock sample coring
Rock sample cutting

9. Uniaxial compressive test (UCS) Coring from rock mass sample
Laboratory test
Uniaxial compressive test (UCS)
Coring from rock mass sample

10. Uniaxial compressive test (UCS)
Laboratory test
Uniaxial compressive test (UCS)
(Failure load)
(Specimen cross sectional area)
No.
Diameter (m)
Height (m)
Load (kN)
Uniaxial compressive strength (MPa) 1
0.05
0.1
48.446
24.67 2
50.566
25.75 3
52.746
26.86
Average
25.76

11. Point load testing machine
Laboratory test
Point load test
Load
Before failure
Point load testing machine
Determination of point load strength based on the application of axial load on rock specimens having a cylindrical or irregular shape.
After failure

12. Point load testing machine
Laboratory test
Point load test
Load
Before failure
Point load testing machine
Determination of point load strength based on the application of axial load on rock specimens having a cylindrical or irregular shape.
After failure

13. Point load test – shape requirements
Laboratory test
Point load test – shape requirements
Diametric test
Axial test

14. Point load test – shape requirements
Laboratory test
Point load test – shape requirements
Block test
Irregular lump test

15. Point load test – shape requirements
Laboratory test
Point load test – shape requirements
Valid diametric test
Valid axial test

16. Point load test – mode of failure Invalid core and axial test
Laboratory test
Point load test – mode of failure
Valid block test
Invalid core and axial test

17. (Equivalent core diameter)
Laboratory test
Point load test
A rock core is loaded diametrically between the tips of two hardened steel cones, causing failure through the development of tensile cracks parallel to the loading direction.
(Failure load)
(Equivalent core diameter)
No.
Diameter (m)
Height (m)
Load (kN)
Is(50) (MPa) 1
0.05
0.075
2.685
1.07 2
2.680 3
3.185
1.27
Average
1.14

18. Correlation between UCS and PL
Sample
Point load index
UCS Estimated
USC value 1
1.07
25.68
24.67 2
25.75 3
1.27
30.48
26.86
Average
27.28
25.76

19. Correlation between UCS and PL
Table 4: Field estimates of intact rock based on Uniaxial compressive strength and point load index (Marinos and Hoek, 2000) G
Term
UCS
(MPa)
PLI
Field estimate of strength
Examples R6
Extremely strong
>250
>10
Specimen can only be chipped with a geological hammer
Fresh basalt, chert, diabase, gneiss, granite, quartzite R5
Very strong
4-10
Specimens requires many blows of a geological hammer to fracture it
Amphibolite, sandstone, basalt, gabbro, gneiss, granodiorite, peridotite, rhyolite, tuff R4
Strong
50-100
2-4
Specimen requires more than one blow of a geological hammer to fracture it
Limestone, marble, sandstone, schist R3
Medium strong
25-50
1-2
Cannot be scraped or peeled with a pocket knife, specimen can be fractured with a single blow from a geological hammer
Concrete, phyllite, schist, siltstone R2
Weak
5-25 **
Can be peeled with a pocket knife with difficulty, shallow indentation made by firm blow with point of geological hammer
Chalk, claystone, potash, marl, siltstone, shale, rocksalt R1
Very weak
1-5
Crumbles under firm blows with point of a geological hammer, can be peeled by a pocket knife
Highly weathered or altered rock, shale R0
Extremely weak
0.25-1
Indented by thumbnail
Stiff fault gouge
**Point load tests on rocks with Uniaxial compressive strength below 25 MPa are likely to yield highly ambiguous results

20. Correlation between UCS and PL
Table : Classes of rock excavatability (Franklin et al., 1970)

21. Triaxial rock testing system
Laboratory test
Triaxial test
Before failure
Triaxial rock testing system
Determination of the compressive strength of intact rock specimens with simultaneous application of confining pressure (up to 70MPa) using the Hoek cell.
After failure

22. Splitting tension test (Brazilian test) Brazilian test machine
Laboratory test
Splitting tension test (Brazilian test)
Load
Brazilian test machine
Brazilian test apparatus are used for indirect measurement of tensile strength of rocks

23. Ultrasonic measurement apparatus
Laboratory test
Ultrasonic test
Ultrasonic measurement apparatus
P and S wave recorder
Determination of the ultrasonic velocity of longitudinal and shear waves in cylindrical rock specimens by calculating the transit time through them as an index to degree of fissuring

24. Longitudinal waves (m/s)
Laboratory test
Ultrasonic test
Table : typical values of longitudinal waves for rocks (Fourmaintraux, 1976)
Rock
Longitudinal waves (m/s)
Gabbro
7000
Basalt
Limestone
Dolomite
Sandstone and quartize
6000
Granitic rocks

25. Portable direct shear test
Laboratory test
Portable direct shear test
Shear of rock discontinuity
Shear test on rock discontinuities
Determination of the shear strength of natural and artificial rock discontinuities.

26. Specimen in slake durability test Slake durability apparatus
Laboratory test
Slake durability test
Specimen in slake durability test
Slake durability apparatus
This test used in the evaluation of the resistance of rocks to disintegration when subjected to different drying and water-immersion cycles.

27. Table of content
Laboratory test
Simple index test
In-situ test

28. Index test Simple index test Objective investigation
Ex) Schmidt test hammer
cheap
simple operation
short time
easy to get
anyone
many times
with small cost
Even a naive engineer
in a wide region
can predict the approximated rock property

29. Schmidt test hammer BANG!! Schmidt test hammer for concrete BANG!!
Schmidt test hammer for rock
attachment
Non-destructive inspection

30. Rebound number & rock properties
deformability
elasticity
rebound number
rebound number

31. Rebound number & rock properties

32. Rebound number & rock properties
Schmidt test hammer measurement in tunnel

33. Table of content
Laboratory test
Simple index test
In-situ test

34. Plate bearing test – in-situ deformability of rock mass
In-situ test
Plate bearing test – in-situ deformability of rock mass
Stiff plate
Fixed point
loading
Jack
fixed line

35. Result of Plate bearing Test
Deformability
Elasticity
Stress [kgf/m2]
Displacement [mm]

36. Interpretation of Displacement
Elastic disp. of discontinuity
Plastic disp. of discontinuity
Elastic disp. of intact rock
Deformability: discontinuity (Plastic disp.+ Elastic disp.)+intact rock (Elastic disp.)
Elasticity: discontinuity (Elastic disp.)+intact rock (Elastic disp.)

37. Pressuremeter Test Dilatometer Goodman Jack
Equally distributed pressure is applied.
Resulting displacement is equally distributed.

38. Dilatometer Test
battery
monitor
pump
cable
probe
rubber tube

39. In-situ Rock Triaxial Test

40. In situ shearing test
Normal load
Shear load
Normal load
Shear load

41. In situ shearing test

42. Result of in situ shearing test
Shear stress
Friction angle f
Cohesion C
Normal stress

43. Borehole hammer
battery
control
cable
probe
hammer

44. Borehole hammer
BANG!!
Electromagnetic hammer

45. Borehole hammer - Principle
increase in velocity 3
departure
uniform motion 2
stop
decrease in velocity
uniform motion 1
contact
behavior
velocity
accereration
time

46. Borehole hammer - Principle
Good rock 3 2 3 2 1
Poor rock
width
velosity
accele-ration
time
time
hight

47. Definition of Response Value
Response value R=
Maximum PMAX
PMAX
Pulse width W W
initial V0 V0
velocity
acceleration
time

48. Thank you very much