Search results for: Free PDF Quiz 2024 High Hit-Rate EMC D-PM-IN-23 Latest Test Report 🍂 Search for ✔ D-PM-IN-23 ️✔️ and download exam materials for free through [ www.pdfvce.com ] 🦞Questions D-PM-IN-23 Exam
-
Commentary on Guideline for landslide susceptibility, hazard and risk zoning for land use management
There have been examples of landslide susceptibility and hazard zoning in use since the 1970’s (e.g. Brabb et al., 1972; Nilsen, et al., 1979; Kienholz, 1978). The hazard and risk maps have usually incorporated the estimated frequency of landsliding in a qualitative sense rather than quantitatively. These examples of zoning have generally been used to manage landslide hazard in urban areas by excluding development in some higher hazard areas and requiring geotechnical engineering assessment of slope stability before development is approved in other areas. In some countries landslide susceptibility, hazard and risk maps are being introduced across the country. For example the PPR (Plans de Prevention des Riques Naturels Previsibles) in France and the Cartes de Dangers or Gefahrenkarten in Switzerland are carried out at the Canton level but with Federal funding support (Leroi et al., 2005).
-
Managing the risks associated with acid sulfate rock in NSW road projects
Acid sulfate rock (ASR) is unweathered rock that contains metal sulfide minerals (commonly iron sulfides). When ASR is exposed to both oxygen and water, oxidation of sulfides leads to the formation of sulfuric acid, sulfates and salts. The probability of ASR being present, can to some extent, be predicted from the geological origins of the rock or later hydrothermal depositions of sulfides. An ASR risk map has been prepared to assist in the pre-design phase of road construction projects.
ASR has the potential to be problematic (depending on concentrations) with respect to environmental, structural and durability risks. It is becoming increasingly common for ASR to be encountered by roadworks in New South Wales where designs include deeper cuttings into unweathered rock that has generally not been the case historically. Examples are given of New South Wales where ASR has been encountered, together with an American example where significant environmental penalties and remedial costs occurred.
Other than low risk geological formations, site investigation for roadworks must include identification of ASR and, where present, screening, detailed testing and interpretation of the distribution of sulfide contents. The details of each aspect of this assessment need to be fully understood. Where ASR is present, the design, specification and construction must include control measures to reduce environmental risks associated with exposing ASR and potentially releasing leachate into the environment. Control measures include dilution, encapsulation and treatment with crushed limestone. Control measures must also be developed to protect structures such as bridges, culverts and retaining walls, stormwater drainage pipes and pavements. The locations of where ASR is placed within the earthworks formation must be limited with respect to environmental, structural and durability constraints. For successful management of ASR in construction projects, careful planning and staging of the earthworks is critical.
-
Analysis And Design Of Geogrid-reinforced Unbound Granular Pavement Over Soft Subgrade For Low Volume Roads
Unbound granular pavements (UGM) are extensively used in low volume roads in rural Australia due to their low cost and availability of local materials. In areas where the subgrade support is of low strength (CBR < 3%), it is recommended to improve existing soft subgrade by stabilisation or by replacing it with better quality selected subgrade materials or by using geosynthetics. Even though current pavement design practices in Australia mention the use of geotextiles as a possible ground treatment option to expedite construction and to assist in compaction of subsequent pavement layers, they do not consider the benefit of using geosynthetic reinforcements to enhance structural performance. Consequently, pavement design procedures and charts are not available for such cases. This study uses two-dimensional (2D) axisymmetric finite element model (FEM) to analyse the behaviour of geogrid-reinforced UGM pavements over soft subgrades. The critical pavement responses such as vertical surface deformation, compressive strain and compressive stress at the top of subgrade are simulated numerically using a commercially available FEM program ABAQUS. The model is verified using published literature-based information. FEM results are then used to develop design charts which can be directly used in practice. These design charts would help pavement practitioners to evaluate the cost-effectiveness of geogrid-reinforced UGM base over conventional unreinforced granular base.
-
Future Of Australian Rail Tracks Capturing Higher Speeds With Heavier Freight
In Australia, quicker and more cost effective commuter and freight transports are essential to cater for the needs of travel demand and supply chains in the mining and agriculture sectors. Such development in coastal areas would necessitate the use of ground improvement techniques in response to environmental legislation and requirements for improved performance and sustainability. In coastal Australia the high cost of track maintenance is the main issue due to poor drainage of soft coastal soils, ballast degradation, fouling (e.g. coal and subgrade soil), differential settlement of track, pumping of subgrade soils and track misalignment due to excessive lateral movements. Hundreds of millions of dollars are spent each year on the construction and maintenance of rail tracks and the existing technical specifications, standards and design are often unable to address these problems. With increased train speeds, the capacity of the track is often inadequate unless more resilient tracks are designed to withstand the substantially increased vibration and cyclic and impact loads. The optimum use of maintenance funds is a challenging task due to the absence of comprehensive methods to predict track longevity even on terrain where the properties of the soils are well established. Until today, the vast majority of Australian track designs have considered ballast and structural fill as elastic granular media, and thus the designers have adopted predominantly empirical methods where true cyclic loading patterns and the onset of plasticity and degradation of track materials are ignored. In many European countries and some parts of Southeast Asia, especially among high speed rail networks, track vibrations are serious concerns. The mechanisms of ballast degradation and deformation, the need for effective track confinement, understanding the interface behaviour and the imperative need for flood protection, time dependent drainage and filtration properties of track materials requires further research to improve the existing design guidelines and Australian Standards for future high speed commuter and heavier freight trains. Field studies on instrumented tracks at Bulli (near Wollongong) and Singleton (near Newcastle) supported by RailCorp and ARTC, were carried out to measure the in situ stresses and deformation of ballast embankments. The application of prefabricated vertical drains (PVDs) to stabilise soft subgrade soils was introduced for the first time in Australia to improve the overall track stability in Sandgate (near Newcastle). The effectiveness of using PVDs was observed through field measurements and finite element analyses. In this keynote paper, the current state-ofthe-art knowledge of rail track geotechnology in Australia and around the world is discussed. The paper focuses on primary research and development of new design and construction concepts for enhanced track performance, highlighting examples of innovations from theory to practice. Through case studies, the paper also introduces predictive and design tools for practitioners via user-friendly approaches.
-
Selected methods of ground improvement for Australian transport infrastructure
In coastal regions of Australia, high population densities and increased traffic have led to a substantial expansion of transportation infrastructure. These developments have necessitated the use of ground improvement techniques in response to environmental legislation and the need for sustained performance. In this paper, a brief overview of innovative ground improvement techniques in major areas such as railway embankments, port reclamation, and landfill operations is provided. Ballasted rail tracks are often placed on freshly quarried aggregate because it is resilient enough for cyclic and impact loads. However, ballasted layers often need periodic maintenance due to deformation and degradation, and while recycled ballast is a cheaper and environmentally viable option, its strength must be investigated beforehand, and different types of geosynthetics to improve the stability and drainage of railway tracks under high cyclic loading also need assessing. Field tests to measure the in-situ stresses and deformations of ballast have been carried out on sections of instrumented heavy haul track at Bulli and Singleton. Stabilization of soft subgrade soils using prefabricated vertical drains (PVDs) and stone columns is also needed to improve the overall stability of track and reduce differential settlement during operation. The effectiveness PVDs can be seen via field measurements and finite element analyses. Due to an increase in trade activities at the Port of Brisbane, Queensland (Qld), new facilities on Fisherman Islands at the mouth of the Brisbane River were constructed (reclamation) on the new outer area (235ha) adjacent to the existing port facilities. A vacuum assisted surcharge load and conventional surcharge scheme in conjunction with PVDs helped to reduce the required consolidation time through the deeper subsoil layers. The design of this combined vacuum and surcharge fill system and construction of the embankment are described in this paper. A 45 ha reclamation at the Outer Harbour extension of Port Kembla in Wollongong, NSW, gave us the opportunity to examine the potential use of coal wash (CW) and steel furnace slag (SFS) as predominant reclamation fill, while laboratory investigations indicated that an optimum CW-SFS mixture would meet most of the geotechnical specifications needed for an effective structural fill. A field application at Penrith Lakes, NSW, of a new methodology using the shear wave velocity (Vs) (i.e. Multichannel Analysis of Surface Waves MASW) and matric suction (ua-uw) or moisture content was investigated. The laboratory results and the results from preliminary field testing indicate that Vs and (ua-uw) trends could predict the compaction characteristics of the soil. The use of sustainable approaches for ground improvement such as bio-engineering, and recycled tyres with waste granular material, is also presented and discussed in this paper.
-
CPT-based design of foundations
The Cone Penetration Test (CPT) is now the most popular in-situ test used worldwide, largely due to its ability to provide continuous and reliable soil profile information in a rapid, cost-effective and digital format. This paper shows how the CPT end resistance (qt) can be used directly in foundation design without the need for intermediate and often subjective interpretation of soil parameters. A simple model illustrating the relative effects of factors controlling the magnitude of qt is first described to provide a basis for correlations between qt and aspects of foundation performance. The development of a variety of design formulations for deep & shallow foundations and walls is then described. It is demonstrated that allowance for previously unaccounted for geometric and other effects greatly enhances the reliability of these formulations compared with previous CPT-based methods.
-
Smarter Transport Infrastructure Embracing Granular Waste And Recycled Rubber – A Circular Economy Perspective
Transport infrastructure in Australia is predominantly composed of compacted granular materials used as base, sub-base, ballast, sub-ballast and capping layers for roads and railways. Replacing traditional natural rockfill with granular wastes and other forms of recycled materials such as rubber is becoming increasingly crucial in a circular economy seeking reduced capital and maintenance costs for sustainable infrastructure. Recent extension of ports and reclamation of low- lying land has also considered compacted granular waste as an alternative structural fill. In Australia, ballasted rail tracks offer the most common mode of transportation including both commuter and freight networks. However, ballast and other granulates progressively degrade under dynamic and impact loads. The degree of degradation will be accelerated due to the growing demand for elevated speeds of passenger trains and heavy axle freight trains. It is, therefore, necessary to develop novel and cost-effective technologies to enhance the longevity and performance of transport infrastructure through amended design and construction. Over the past two decades, numerous studies have been conducted under the leadership of 1st Author to investigate the ability of recycled rubber mats/pads, as well as waste tyre cells and granulated rubber to improve the stability of substructure materials for both railways and roads. This keynote paper presents an overview of these novel methods and materials based on comprehensive laboratory tests using iconic testing facilities. Test results from comprehensive laboratory tests and field studies have indicated that the use of energy-absorbing rubber inclusions can substantially improve overall stability. The findings reflect the following: (i) the inclusion of recycled- rubber based synthetic energy absorbing layers significantly attenuates the magnitude of the dynamic load with depth and particle breakage, (ii) an alternative solution by using coal wash-rubber crumb mixtures as capping layer is also introduced in this study, and the compressibility of the rubber is captured by cyclic compression triaxial tests, (iii) the installation of under ballast mats (UBM) for railways significantly reduces permanent vertical and lateral deformation of the track as well as reducing ballast degradation, (iv) waste tyre cells infilled with granular aggregates effectively increase the stiffness and bearing capacity of the capping layer and assist in mitigating excessive lateral displacement, and (v) field tests indicate geogrids and shock-mats are efficient methods to reduce the substructure displacement and particle breakage. These research outcomes provide promising approaches to transform traditional transport infrastructure design practices to cater for future high axle rolling stock and for enhanced longevity and reduced maintenance of all modes of transport corridors.
-
Geotechnical challenges for development In the Hunter Region – Key Figures 1, 2 and 3
This paper presents an overview of the geology of the wider Hunter Valley and Central Coast regions of New South Wales and a discussion of some of the consequences that present challenges to the geotechnical engineering profession. The contrasting structural styles of the folded and faulted Southern New England Fold Belt and the relatively flat-lying, undeformed Sydney Basin are described and compared. Consideration is given to the potential for instability arising from the combination of competent, blocky conglomerates, low strength claystones and coal seams, particularly within the Newcastle Coal Measures. Of the wide variety of challenges that arise from such a regionally diverse range of geological conditions, three areas of practice are given special discussion due to their local importance. These are the treatment of Quaternary sediments that underlie many of the more intensely developed areas; the distribution, properties and treatment of reactive clay soils that are well developed in all geological environments and the treatment of problems due to the risk of mining-induced subsidence on development.
-
Classification of sandstones and shales in the Sydney region: A forty year review
The classification system developed in 1978 by a sub-committee of the Australian Geomechnics Society in association with guideline allowable bearing pressures on the Triassic sandstones and shales of the Sydney Basin has proven to be useful as a communication tool on many and varied projects in Sydney and its surrounds. However, the classification system has also been misused.
In this 2nd update of the original paper, the authors:
- indicate uses of the associated classification system, or components thereof, for design of prestressed ground anchors, and for preliminary groundwater analyses,
- show that a modified system is appropriate for linkage to tunnel support design,
- document why the system should not be used in assessments of slope stability, excavatability and rock cutting, and
- expand the guidelines for foundation bearing pressures and socket side shear values based on extensive research testing, and field experience, gained in the 40 years since the original publication.
-
Soil stiffness for shallow foundation design in the Perth CBD
Foundation systems for high-rise structures in the Perth CBD include the whole range of footing types: individual spread footings, single rafts, piles, and piled rafts. Of these, raft foundations are the most common. The design of raft foundations (and indeed all foundation types) relies heavily on calculations of the anticipated total and differential settlements. For these calculations, the most crucial material parameters are the stiffnesses of the soils underlying the foundation. In the Perth CBD, the soil types consist of interbedded layers of dense to very dense sand or fine gravel, and stiff to hard clays, overlying bedrock. In the period since the 1970s, when most of the current high rise structures in the CBD were built, a number of methods of determining the soil stiffness have been used. Very little information is available regarding the actual settlement performance of these structures. However, two important publications from the 1970s provide back-analysed stiffness parameters from the measured performance of 4 moderate rise structures (up to 40 storeys high) and these are regarded as benchmark values. The paper discusses the various methods used in Perth for determining stiffness, both ‘traditional’ and ‘modern’, and the results obtained using these methods are compared to the benchmark values. Data from a number of sites, mostly at the west end of the CBD, are discussed in detail, as a number of insitu test methods for determining stiffness have been used at some of these sites, including seismic CPT, Marchetti dilatometer (DMT) and self-boring pressuremeter (SBP). Some comments are also included about stiffnesses of sands in other parts of the Perth area, compared to the CBD area.