It is proposed to construct a 3m diameter, 50m long tunnel, heading 0950, through the andesite lava flow at Maori Bay (Muriwai). As part of the preliminary investigations you have been asked to prepare a report assessing the suitability of the rock mass for this project, & provide an initial indication of rock suitability (including stand-up time) & support that will be required in the tunnel.
Attached is a sheet from a preliminary defect survey carried out on the exposed face of the lava flow.
A) Describe the local geology (Maori Bay – Muriwai)
- That is, rock types & structures, etc at and around the site.
- Find formation & group names from an appropriate geological map or publication.
B) Represent the defect survey graphically (not in a table).
C) Estimate stand-up time using the RMR System (showing workings).
D) Comment on the ease & possible methods of excavation of the tunnel.
E) Identify possible methods for tunnel support (if any is needed) as given by the RMR system.
Your report should also contain:
A) A map showing the location of the site.
B) An estimate of rock material (compressive) strength of the lava flow.
C) An estimate of what the RQD would be in a horizontal bore hole (showing workings).
D) A list of all references used. These must be cited in the report using the APA System
E) Report will not be marked past 8 pages including references.