Learning Old lessons – The Value of Old Fashioned Mapping
RDCL has been involved in a very interesting project with PT GRM (Ground Risk Management) in Indonesia. While the project is confidential, the lessons are interesting and relevant to where we work in New Zealand, the Philippines and Indonesia. All areas with highly variable ground conditions, high rainfall and often unmapped and under explored areas.
A project was midway through earthworks for a large Processing Plant and appurtenant structures. Following a period of intense rainfall large cracks and ‘heave’ blocks were observed across the earthworked building platform. Subsequent engineering geological mapping of the immediate area revealed a very large landslide had been reactivated, with evidence of ground rupture, disrupted trees and tension cracks covering an area of more than 400,000m2.
With no previous engineering geological mapping of the area (or no information available relating to this) the company was forced to take a “back-to-basics” approach going back to the ‘old school’ investigation techniques we all learnt in Engineering Geology lectures at university.
Investigations included detailed Stereo Photo assessment to better refine the areas to be mapped, and extensive engineering geological mapping to observe signs of relict, large scale instability (if present), and to generate engineering geological maps.
Hazard and risk profiles of proposed sites for major infrastructure were generated to help the client make a decision based on Capital and Operational Expenditure AND Engineering Geological Risk.
We’d like to thank the GRM guys for a chance on this job, and recognise Joy Hoverd’s “capital efforts” mapping in tough conditions.
