Rock mechanics engg

1. INFORMATIONREQUIREDFORROCKMECHANICS
MODELLINGANDDESIGN
MUHAMMAD ANUS
14MN36
DEPARTMENT OF MINING
ENGINEERING
MEHRAN UNIVERSITY OF
ENGINERERING AND
TECHNOLOGY,
JAMSHORO
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2. WHAT IS MODELLING ?
Process of creating and analyzing a physical
model to predict its performance in the real
world.
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3. WHAT IS ENGINEERING DESIGN ?
It is the process of devising a system, component
or a process to meet the desired needs.
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4. OBJECTIVES
QUESTIONS…
 Is supporting information is adequate ?
 Have all parameters included In modeling ?
 Are the values accurate and precise ?
ANSWER IS..
“The information required is a function of the
modeling methods chosen for the initial and
final design”.
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5. Flowchart for rock mechanics modeling & design
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6. A: Pre-existing standard methods
Information required :
 In situ stress
 project information
 orientation of excavation cross-sections
 rock mechanics parameters such as
 Uni-axial compressive strength, , , , C.
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7. B: Analytical methods
 Same as Method A
 Require parameters used in the analytical formulae.
Example
Kirsch solution-----Field stresses
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8. C : Basic numerical methods
Two numerical approaches;
1. CONTINUUM APPROACH:
a. Excavation type
b. project information
c. Mechanical parameters of intact rock
2. DISCRETE APPROACH:
a. Geometry
b. mechanical parameters of faults/joints
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9. D: Extended numerical methods
Require complete Information on:
 Inhomogeneity
 Thermal parameters
 Hydrogeological parameters
 Hydrogeochemical parameters
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10. Precedent type analysis (PTA)
PTA done by using different Empirical approaches.
 Rock mechanics parameters
 Rock mass structure
 Weathered degree
 Tunnel geometry
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11. Rock mass classification
Information required :
 Q-system
 Rock Mass Rating (RMR)
 Geological Strength Index (GSI)
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12. REFERENCES
 “Numerical methods in rock mechanics” by L.
Jinga & J.A. Hudson.
 “Specifying the information required for rock
mechanics modelling and rock engineering
design” by Xia-Ting Feng & John A.Hudson.
 “When is there sufficient information from the
site investigations” by Andersson JA, Munier
R, Strom A, Soderback B, Almen KE,
OlssonL.
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