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INFORMATION REQUIRED FOR ROCK MECHANICS MODELLING AND DESIGN

MUHAMMAD ANUS14MN36 DEPARTMENT OF MINING ENGINEERINGMEHRAN UNIVERSITY OF ENGINERERING AND TECHNOLOGY, JAMSHORO

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WHAT IS MODELLING ?Process of creating and analyzing a physical model to predict its performance in the realworld.

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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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OBJECTIVESQUESTIONS

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.4

Flowchart for rock mechanics modeling & design approaches5

A: Pre-existing standard methods Information required :

In situ stress

project information

orientation of excavation cross-sections

rock mechanics parameters such asUni-axial compressive strength, , , , C.

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B: Analytical methodsSame as Method ARequire parameters used in the analytical formulae.ExampleKirsch solution-----Field stresses

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C : Basic numerical methods Two numerical approaches;

CONTINUUM APPROACH:Excavation typeproject informationMechanical parameters of intact rock

2. DISCRETE APPROACH:Geometrymechanical parameters of faults/joints

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D: Extended numerical methods

Require complete Information on:

Inhomogeneity

Thermal parameters

Hydrogeological parameters

Hydrogeochemical parameters

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Precedent type analysis (PTA)

PTA done by using different Empirical approaches.

Rock mechanics parameters

Rock mass structure

Weathered degree

Tunnel geometry 10

Rock mass classification

Information required :

Q-system

Rock Mass Rating (RMR)

Geological Strength Index (GSI) 11

REFERENCESNumerical 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.12

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