Page 6 of 26 First Next Previous Last

Engineering Geology for the Snowy Mountains Scheme

No works come within the small area affected by this third glacial stage, The effects of the older second and third glaciations have been much modified by normal river erosion and denudation in the period following the glaciations, particularly at the lower levels where the streams are now entrenched well below their former glaciated floors. The glaciations generally, therefore, do not have a direct effect on many works. One project, however, the proposed Kosciusko Dam on Spencer’s Creek, a tributary of the Upper Snowy River, is greatly affected.

Rock Weathering:

Much of the undulating plateau country, the broad mature valleys and even most of the higher slopes of the steep-walled youthful valleys entrenched below the plateau surface, such as those of the Tumut and Upper Snowy Rivers, are covered with a mantle of residual soil often of great thickness formed by the weathering in place of the bed-rock. Only along the beds of actively degrading streams and the lowest hundred feet or so of the major valleys is it common to find fresh rock exposed at the surface.

Determination of the extent of the weathering and the nature and engineering properties of the products of weathering are among the most frequent and important geological problems encountered. They arise in connection with the investigation of the sites of practically every dam, tunnel and power station. Weathering often severely limits the number of possible quarry sites for concrete materials, rock fill and rip-rap. Residual soils often provide the most suitable and abundant sources of earth-fill for dam embankments and road building materials. Weathering greatly affects the location and design of roads in steep country.

Apart from these direct effects on the engineering works, the widespread blanket of soil makes geological mapping difficult by concealing the underlying rock and, in particular, it often tends to obscure weak-zones in the bed-rock, since both sound rock and weak rock are reduced by weathering to a similar soil.

Weathering is by no means uniformly developed throughout the area. The most important factors influencing its development are the rock type, the local geological structure and the erosional history of each particular locality.

The granitic rocks are the most abundant and widespread rocks in the area, and it was therefore necessary at an early stage in the investigation to closely define the terms used to describe the various degrees of weathering of granitic rocks in order that descriptions of weathered rock exposed in outcrops, excavations, or in drill cores made by different geologists would be consistent and would indicate the engineering properties of the materials. Weathering of granite usually follows a regular pattern of development, and the degree of weathering can be consistently judged. Weathering in this case is mainly chemical weathering, recognized by the softening and decomposition of the felspars to clays, decay of the biotite mica, frequent brown discoloration throughout the fabric of the rock due to limonite, and a tendency for the rock to break into individual mineral grains, all leading to a reduction in its strength compared with its fresh state.

Details for this article:

Engineering Geology for the Snowy Mountains Scheme

X

Author: Moye, D. G (1955)

Article Title: Engineering Geology for the Snowy Mountains Scheme

From: J.I.E.Aust., Vol. 27 No.10 pp287-298

Other Available Articles

Engineering geology for the Snowy Mountains Scheme

Moye, D.G. (1955)

Engineering geology for the Snowy Mountains Scheme.

J.I.E.Aust., Vol. 27 No.10 pp287–298

Rock Mechanics in the Investigation and Construction of T.1 Underground Power Station, Snowy Mountains, Australia

Moye, D.G. (1958)

Rock Mechanics in the Investigation and Construction of T.1 Underground Power Station, Snowy Mountains, Australia

In Engineering Geology Case Histories No.3 123–54 Geological Society of America 69 (12) p.1617

Existence of high horizontal rock stresses in rock masses.

Moye, D.G. (1962)

Existence of high horizontal rock stresses in rock masses.

Proc. Third Australia-New Zealand Conference on Soil Mechanics and Foundation Engineering. pp 19–22

Seismic Activity in the Snowy Mountains Region and its Relationship to Geological Structures

J. R. Cleary, H. A. Doyle, D. G. Moye (1964)

SEISMIC ACTIVITY IN THE SNOWY MOUNTAINS REGION AND ITS RELATIONSHIP TO GEOLOGICAL STRUCTURES

Journal of the Geological Society of Australia

Unstable rock and its treatment in the Snowy Mountains Scheme.

Moye, D.G. (1965)

Unstable rock and its treatment in the Snowy Mountains Scheme.

Proc. 8th Commonwealth Mining and Metallurgical Congress, Australia & New Zealand. Vol. 6, p. 423–441.

Diamond drilling for foundation exploration

Moye, D.G. (1967)

Diamond drilling for foundation exploration.

Paper 2150 presented at I.E.Aust. Site Investigation Symposium, September 1966. In Civil Engineering Transactions, with Discussion, April 1967.

Geology in Practice

Moye, D.G. (1970)

Geology in Practice. Presidential Address Section 3, Geology, ANZAAS Meeting.

Australian Journal of Science, 32 (12) June, p454–461.

* This paper was presented when Dan had been Director of Exploration of BHP for 3 years.

Field and Laboratory Tests in Rock Mechanics

Alexander, L. G (1960)

Field and Laboratory Tests in Rock Mechanics

Proceedings, 3rd Australian-New Zealand Conference on Soil Mechanics and Foundation Engineering, Sydney Australia, 1960, pp. 161–168.

Discussion at Technical Session No. 9—Rock Mechanics

Alexander, L. G. Moye, D. G. (1960)

Discussion at Technical Session No. 9—Rock Mechanics

Proceedings, 3rd Australian-New Zealand Conference on Soil Mechanics and Foundation Engineering, Sydney Australia, 1960, pp. 254–250