Landslide hazard and risk assessment along a railway line

Various methods of landslide hazard assessment and zonation, have been developed in the past. Some research has also progressed towards the assessment of consequence and risk related to slope instability. This thesis is a contribution towards the development of rational and systematic approaches, qualitative and quantitative, for the assessment of landslide hazard and risk. Slope stability and the occurrence of landslides is an interdisciplinary area of study and inputs may be required from some or all of the following discipline areas: geomechanics, engineering geology, geomorphology, hydrology, hydrogeology, statistics and probability theory, and decision science. In order to assess landslide hazard, it is very useful but not sufficient to carry out slope stability analyses. Attention has to be given to the basic causes and mechanisms as well as to the triggering agents. Although the factors which influence the occurrence of landslides are now well known and mechanisms of failure are recognised, prediction of future events is difficult. In addition to analytical and experimental methods, observational approaches are very important for understanding the processes and mechanisms and for assessing the hazard. Systematic use of observational data, such as those from inclinometers, piezometers and rainfall stations has been demonstrated in this thesis. The current project focuses on landslide hazard in the urban context and, more specifically along transportation routes such as railway lines in hilly areas. A three-level strategy (Type I, Type II, Type III analyses) which is also described as multi-level or integrated hazard and risk assessment has been proposed, developed and successfully used along the Unanderra to Moss Vale Railway Line constituting a 32.5km of track length. Data are often not sufficient or of the highest quality to carry out quantitative studies. For many years, only qualitative, site-specific approaches (Type I) based on minimum site investigation have been used in practice. These approaches, in which engineering and geological judgment is of paramount importance, are still found to be useful. In particular, comprehensive Type I assessment data can be very useful for regional or Type II analyses. There is an increasing recognition of the need for more systematic and quantitative approaches which makes use of historical and observational data to the fullest. Type II analyses explore spatial and temporal relationships along the whole area considering a number of influencing factors as well as the triggering agent such as rainfall. This has enabled the preparation of relevant hazard maps for the study area. Type III analyses are detailed site-specific analyses which include conventional slope stability assessment as well as the recurrence intervals and hence the annual probabilities of landsliding. These are the dominant aspects of hazard. In this thesis, these relatively rigorous approaches are extended further to quantitatively assess the consequences to human life and the related risk. The assessments are tailored not only to all available geotechnical and rainfall data but also the information concerning the railway operations and the infrastructure. Consideration of economic loss and other environmental consequences on a quantitative basis was outside the scope of this thesis. Even these quantitative approaches requires a considerable component of engineering judgment. As part of this thesis a comprehensive Type I method along with an original set of field sheets utilising a weighting approach has been developed. It has been named the University of Wollongong (UOW) method. In this approach risk is assessed by means of hazard and consequence matrix and a substantial component of consequence assessment framework is incorporated, an aspect in which other similar methods used in New South Wales (Australia) were found to be lacking. The UOW method and several other Type I methods were tested and compared. This process allowed strengths and weaknesses to be identified for each method. It is widely recognised that predictions concerning slope stability are often difficult make. Hence, deterministic approaches must be complemented by the use of probability concepts. Therefore, one aspect of the methods proposed in this thesis is the estimation of annual failure probabilities and/or recurrence intervals of landsliding. This can be particularly useful for Type II and Type III approaches, provided relevant data are available. The main triggering agent in the study area is rainfall. Therefore, available historical data on rainfall and rainstorms has been very useful in carrying out Type II and Type III analyses when combined with observational data on subsurface water levels and on slope movements. Type II analyses have been found useful to identify the most susceptible geological units. GIS-based hazard maps of the Unanderra to Moss Vale Railway Line have also been produced on the basis of such an assessment. Type III analyses was carried out for three Case Studies which consist of 4 sites. Risk of human casualty for a passenger either on a tourist train or on a freight train was determined on a quantitative basis for Type II and Type III analyses. In most cases risk was found to be above the tolerable or acceptable levels as proposed by some previous researchers. These three Types of hazard and risk assessment complement each other. An integrated approach using these three types of methods can be a very powerful tool for managing risk. A key feature for quantitative hazard and risk analyses (Type II and Type III analyses) the estimation of the annual probability of landslide recurrence, based on the recurrence interval. In this thesis the concept of critical rainfall triggering landslide event has been proposed. Each landslide site may have a unique landslide triggering rainfall. A quantitative estimation of the conditions for landslide recurrence was made for each of the three landslide sites taking into consideration the historical rainfall data over several decades as well as the detailed observational data for each site

Aspects of recent landslide research at the University of Wollongong

This paper introduces the issues which are of critical importance to landslide hazard and risk assessment and management. These include understanding of probability and consequence, the separation of the role of site-dependent factors from that of influencing/triggering natural events and the factors influencing target levels of risk. The research completed at the University of Wollongong is then outlined. This includes the development of an observational approach based on monitoring of subsurface movements at individual sites and appropriate use of rainfall data in terms of the concept of annual rainfall percentage exceedance time (ARPET). Attention is then focused on current research including the development of a hazard-consequence matrix approach for risk assessment at individual sites. Another important research task concerns the development and assessment of magnitude - cumulative frequency relationships for landslides in the study area

Landslide risk assessment - development of a hazard consequence approach

Several Landslide Hazard and Risk Assessment methods have been developed and used in the State of New South Wales (NSW), Australia. The Rail Services Australia Geotechnical Services and the Roads and Traffic Authority of NSW have each developed Risk Assessment procedures suitable to their own specific needs. A generic risk management methodology is presented in the Australian Standard/New Zealand Standard (AS/NZS) 4360:1995. An approach similar to the (AS/NZS) 4360:1995 Risk Management Standard has been applied by a NSW State Emergency Services geotechnical team (which included one of the writers) to 191 problem sites in the Wollongong Area, following a major rainstorm event in August 1998, (GTR, 1998). The writers at the University of Wollongong (UOW) are developing a more comprehensive hazardconsequence approach. This has required careful and precise definitions of the terms and parameters being used. It is the writers\u27 intention that this will lead to effective, efficient and consistent assessments of hazard and risk. Field Data Sheets based on the stated concepts are being developed and tested at several field sites. The formalisation of field data collection will provide a good mechanism for consistent data capture. Data collected in this manner is most suited for management in a database environment

Hazard and Risk Assessment of Rainfall - Induced Landsliding along a Railway Line

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Myanmar (2003): Peer Ethnographic Research with Sex-Workers and Male Students in Yangon

This report presents key findings of peer ethnographic research carried out by PSI Myanmar among female sex-workers and male students between May and August 2003. The peer ethnographic tool has been designed to enable agencies and programmes to gain an in-depth understanding of how people perceive and experience their social worlds, specifically in relation to sexual and reproductive health, through documenting their conversational interactions with peers around key issues. Fifteen sex-workers and fourteen male students were trained as peer researchers and were the key informants for this study. Each of the PERs interviewed 3-4 peers, and these interviews, together with the results of debriefing sessions and synthesis workshops, provide the raw data on which this report is based

Boosting robot-assisted rehabilitation of stroke hemiparesis by individualized selection of upper limb movements – a pilot study

Abstract Background Intensive robot-assisted training of the upper limb after stroke can reduce motor impairment, even at the chronic stage. However, the effectiveness of practice for recovery depends on the selection of the practised movements. We hypothesized that rehabilitation can be optimized by selecting the movements to be practiced based on the trainee’s performance profile. Methods We present a novel principle (‘steepest gradients’) for performance-based selection of movements. The principle is based on mapping motor performance across a workspace and then selecting movements located at regions of the steepest transition between better and worse performance. To assess the benefit of this principle we compared the effect of 15 sessions of robot-assisted reaching training on upper-limb motor impairment, between two groups of people who have moderate-to-severe chronic upper-limb hemiparesis due to stroke. The test group (N = 7) received steepest gradients-based training, iteratively selected according to the steepest gradients principle with weekly remapping, whereas the control group (N = 9) received a standard “centre-out” reaching training. Training intensity was identical. Results Both groups showed improvement in Fugl-Meyer upper-extremity scores (the primary outcome measure). Moreover, the test group showed significantly greater improvement (twofold) compared to control. The score remained elevated, on average, for at least 4 weeks although the additional benefit of the steepest-gradients -based training diminished relative to control. Conclusions This study provides a proof of concept for the superior benefit of performance-based selection of practiced movements in reducing upper-limb motor impairment due to stroke. This added benefit was most evident in the short term, suggesting that performance-based steepest-gradients training may be effective in increasing the rate of initial phase of practice-based recovery; we discuss how long-term retention may also be improved. Trial registration ISRCTN, ISRCTN65226825, registered 12 June 2018 - Retrospectively registered

Correction to: Boosting robot-assisted rehabilitation of stroke hemiparesis by individualized selection of upper limb movements – a pilot study

The original article [1] contained a minor error in the following sentence in the Discussion