Effective design is critical for the stability and creation of a safe working environment for underground excavations. The module commences with a critical review of input data required for design of underground excavations (building on previous knowledge obtained in the year 2 module ‘Geotechnics’ or equivalent). The model investigates factors influencing the design of underground excavations, including both discontinuity and stress-controlled instability. The module is not recommended for interdisciplinary pathways. 

The module provides specialist analysis and design skills associated with the tunnelling, underground mining and related industries.  The module provides problem-solving, data-handling and evaluation skills.  The module also provides an opportunity for you to develop an awareness of risk assessment applied to underground excavation design.

Where appropriate, case history information is used to emphasize important aspects associated with data variability and its influence on design.

Computer-based design exercises are used to emphasize and consolidate key aspects of how stress redistribution and discontinuity characteristics affect excavation stability and choice of appropriate stabilization methods. 

On successful completion of this module, you should be able to:
 

Module Specific Skills and Knowledge:

1 assess critically the use of rock engineering for the design of underground excavations in the mining, civil, geotechnical, environmental and related industries;

2 evaluate critically the role and limitations of analytical and computer methods in underground excavation design;

3 assess critically the data requirements for the design of underground excavations, including considerations of data variability and risk assessment;

4 choose an appropriate tunnelling technique for varying rock and soil material.
 

Discipline Specific Skills and Knowledge:

5 evaluate and apply knowledge to specific design tasks;

6 choose appropriate design from critical evaluation of available data;

7 undertake synthesis of information and create responses based on advanced knowledge.
 

Personal and Key Transferable / Employment Skills and Knowledge:

8 apply personal data-handling skills through critically evaluation of a design problem and produce, to a strict deadline, detailed recommendations/reasoned arguments for an appropriate solution;

9 utilise a full range of computer-based learning resources as an autonomous learner.

The module commences with a review of critical input parameters for design of underground excavations, emphasising the differences between discontinuity controlled behaviour and rock mass material controlled instability. Excavation results in a redistribution of the in-situ stress field, induced displacements within the rock mass in response to excavation and perturbation of the groundwater.  

Data visualisation is a key part of the module, using design-based software for enhanced learning and awareness of both stress-controlled and discontinuity-related failure of underground excavation. The module covers both tunnelling and underground excavation design. Key subject areas studied within these two themes include:

- underground excavation design: design methodology (including empirical, analytical and observational design);

- stereographic analysis of roof and sidewall instability;

- stabilisation techniques/methods including reinforcement and support;

- and a review of underground excavation monitoring and instrumentation;

- 2D and 3D stress and strain;

- Kirsch equations, shape factors, non-circular stress redistribution, effects of discontinuities on excavation stability, wedge analysis, design in sedimentary rock, rock mass-support interaction, tunnel support techniques and their application;

- pillar design, including estimation of pillar stress and pillar strength;

- use of rock mass classification;

- empirical hanging-wall design, including Laubscher MRMR and Stability Graph Method;

- rock engineering systems approach.

The module also includes a review and use of commercially available software for design purposes and an awareness of deterministic versus probabilistic design and risk analysis applied to slope design. Aspects of blasting realted to underground excavation will also be undertaken.

Tunnelling aspects include:

- overview of tunnelling applications;

- soft ground tunnelling methods;

- lining design;

- NATM;

- ground treatment;

- equipment selection;

- spoil disposal and management;

- pipejacking;

-micro-tunnelling;

- ventilation;

- lighting.

ELE: http://vle.exeter.ac.uk/

Web based and Electronic Resources:

http://www.rockeng.utoronto.ca/roc/Hoek/Hoek.htm – Hoek’s Corner

Reading list for this module: