Australian Geomechanics Society Newcastle, New South Wales – 2002 Meetings

• October 17, 2002

  Assessment of Regional Landslide Hazard

  Patrick MacGregor, Consulting Engineering Geologist

  The process of assessment of the risk of landsliding involves consideration of the likelihood of a landslide event occurring and also the consequence of that event. A primary requirement is an estimation of the level of hazard that exists i.e. whether a landslide could occur, and if so, its probable frequency. This estimation is commonly based on observation of site conditions, historical records and a considerable input of judgement based on experience. As a result it has been found that different practitioners have estimated different hazard levels for the same site.

  In the situation where there may be many sites, or a large area, to be assessed, and also a lack of experienced personnel, it is necessary to establish some system, which enables uniformity of approach and in particular identifies problems sites, and also those sites with an acceptable hazard level.

  The presentation will describe a system that has been developed and used to estimate landslide hazard in more than 800 sites in Victoria and Queensland.

• March 27, 2002

  Construction of the Suez Canal

  Mamdouh Hamza, Ph.D, Hamza Associates

  The earliest project to connect the Mediterranean Sea and the Red Sea dates back to 1920 BC. Construction of the Suez Canal, which commenced in 1859, has had a major impact on Egypts modern history, as it resulted in Egypt becoming backrupt in 1876, and being occupied in 1882 and later engaged in four wars. The lecture will briefly describe some on the many earlier plans for a canal, the history and politics of the current Canal's construction, the engineering challenges, and the enormous obsticles that had to be overcome.

• May 8, 2002

  The environmental improvements of the Shingmun River, China

  Dr. Paul Kau, Golder Associates, Hong Kong

  The Shing Mun River is a man-made flood water diversion channel constructed in the 1960s, passing through several major residential areas in the Kowloon / New Territories District of Hong Kong. Up until the early 1990s, the river has been the recipient of various forms of municipal and light industrial waste and discharge, resulting in the contamination of the river sediments. In March 2001, the Civil Engineering Department of Hong Kong initiated the Stage I works of the Environmental Improvements of Shing Mun River, comprising bioremediation and dredging works totaling approximately HK$100M (AUD 25M) over a 18-month period. This presentation will describe some of the pre-works activities carried out and provide details of the bioremediation technology currently used for the works.

• May 31, 2002

  E.H. Davis Lecture - Soil structure interaction

  A/Prof John Small, University of Sydney, NSW

  Often there has been a separation in the design of foundations for buildings into the structural component and the foundation. Structural engineers have tended to use simple soil models such as springs to represent the foundation, while foundation engineers have often neglected the foundation stiffness and treated the structural as being perfectly flexible. However, it is often desirable to combine both structural and geotechnical aspects, as this can lead to improved design.

  In the lecture, some of the issues involved with foundation design are discussed, and some of the limitations of simple techniques are pointed out. Some examples are given of techniques and software that have been developed by the speaker and others to aid in the design of raft foundations and piled-raft foundations. Examples are given of high-rise structures that have been constructed in Germany, the Middle East and in South-east Asia, and some of the advantages of piled-raft foundations are discussed.

  Although the lecture is mainly concerned with foundation design, it also covers some other topics of interest such as the behaviour of pavements and earth and rockfill dams.

  Professor John Small is a graduate of King's College London (1972), with a PhD in geomechanics from the University of Sydney in 1977. He has worked for Coffey Partners, the University of Newcastle, and was a Visiting Fellow at the University of Hong Kong in 1982. He joined the University of Sydney in 1983, where he is currently an Associate Professor and Associate Dean of Engineering. He has authored 105 papers in the field of geomechanics, and has a particular interest in numerical analysis of geomechanics and geotechnical software.

• June 26, 2002

  Seminars on Landslide Risk Management

  Landslide Roadshow

  In March 2000, the paper "Landslide Risk Management Concepts and Guidelines" was published in the journal Australian Geomechanics. The paper provides a benchmark for the terminology and methodology of Landslide Risk Management.

  The Coroner's report on the 1997 Thredbo landslide recommended adoption of the paper. Emergency Management Australian (EMA) have identified the AGS 2000 Guidelines as part of the emergency planning and management strategy in their Guidelines for Emergency Management Practice.

  Adoption of the AGS 2000 Guidelines requires some knowledge and understanding of the concepts. Landslide risk assessment requires input from trained and experienced practitioners in landsliding and slope processes, usually being geotechnical engineers and engineering geologists. Local authorities who receive landslide risk assessments need to understand the basis of the assessment and the implication of the acceptance of the risk that has been identified by the assessment and the management options proposed. Civil and structural engineers, who design stabilisation works for the management options also need to be aware of the methodology adopted. The seminars are intended to demonstrate how the concepts and guidelines may be used.

  EMA have sponsored the seminars which will be presented at locations around Australia. The seminars will briefly outline the AGS 2000 paper and then present a number of case history type papers demonstrating how the methodology has been applied to "real" problems.

  Who Should Attend: Geotechnical engineers, engineering geologists, land use planners, representatives from government at all levels responsible for accepting and/or implementing development in areas where landslide risk is a factor, civil and structural engineers, risk managers, emergency managers.

• August 21, 2002

  Maryland reactive Soils Field Site

  Dr Stephen Fityus, University of Newcastle

  Dr Stephen Fityus has a background in engineering geology and geotechnical engineering, from undergraduate studies in engineering and geology at the University of Newcastle. He worked for 4 years, mostly in the local geotechnical industry, before returning to the University of Newcastle to undertake his PhD on the topic of unsaturated soils, in which reactive soil behaviour featured prominently. He has been associated with the Maryland reactive soil project since its inception, and continues to pursue research in this area. He is currently a lecturer in geotechnical engineering at the University of Newcastle.

  The Maryland reactive soils field site was established in 1993 to provide a wide variety of quantitative field data on reactive clay soil effects in the Newcastle region. The field site, located in an area which has been zoned for future residential development, lies within an urban development corridor which is dominated by moderately and highly reactive clay foundation conditions. The site includes a flexible ground cover, to simulate the moisture barrier effects of a 10m by 10m Class M slab; a loaded 10m by 10m class M reinforced concrete slab;and a variety of instrumentation to monitor moisture and suction changes.

  The site has been monitored on a semi-regular basis since its establishment. Stephen will discuss the geotechnical and geological characteristics of the site; the adequacy of the ground movement prediction method described by AS2870; the time taken for the moisture conditions beneath the covered areas to stabilise, and the equilibrium moisture distributions.

• September 11, 2002

  Mine Void Remediation for the West Charlestown Bypass, Newcastle

  Ben Rouvray

  The earthworks associated with the West Charlestown Bypass in Newcastle are currently nearing completion. The project comprises 6km of dual carriageway motorway in an urban environment, extending from the Pacific Highway at Windale in the South to Charlestown Road, Kotara South, in the north.

  A 1km length of the Bypass, at the northern extent of the works, traverses old underground mine workings with overburden depths as shallow as 5m ranging up to 30m. The mine workings are within the Australasian Coal Seam and were undertaken by two collieries, initially in the 1800’s by the Australasian Coal Company and later in the early 1900’s by the Newcastle Myall Colliery.

  The Bypass design was required to be safe and serviceable considering the potential impact of ongoing mine subsidence associated with these workings. A number of treatment options were considered with the adopted design including a combination of excavate, collapse and backfill of shallow mine workings, and grouting of voids where the workings are located at greater depths.

  This presentation will cover the pre construction investigations, including discussion of the methodologies adopted and their success, the design options considered, and the recently completed mine void treatment works.

• October 22, 2002

  Aspects of Development of Sydney Airport

  Mike Thom, Director, Douglas Partners Pty Ltd

  The first significant development at Sydney Airport took place immediately after the Second World War when Cooks River was diverted to enable construction of the North-South and East-West Runways. This work was concluded in the late 1950's by which time the present airport layout was essentially established.

  Since the early construction work at the Airport, development has occurred episodically with the second phase comprising a major runway extension into Botany Bay and construction of various infrastructure beneath the runway extension. This was followed by development in the present International Terminal area including major site preparation works to convert swamp land into an area suitable for building and pavement construction.

  The talk will outline some history of the development of the Airport, together with some of the geotechnical problems which were encountered by the early engineers. The main part of the talk will focus on settlement at Sydney Airport especially around the International Terminal where up to 200 mm of post construction settlement has been recorded since 1971. The talk will also look at a significant stability problem alongside the northern ponding area where parking areas for jumbo aircraft have been located. The talk will also provide some data on piling for Terminal C at the International Terminal where significant uplift loads were required to prevent flotation of the Terminal Building.

  The three areas of geotechnical difficulty that will be discussed during the talk are just a few of the problems that have been encountered during the 50 years development at the Airport. The talk will be illustrated by many historical photographs which have been collected by the author.