Hydraulic conductivity and swelling pressure of GCLs using polymer treated clays to high concentration CaCl(2) solutions

A Geosynthetic Clay Liner (GCL) is a frequently used h ydraulic barrier system designed to impede the flow of contaminated leachate into the environment. The main objective of this barrier system is to maintain a low hydraulic conductivity that is determined by the bentonite fraction. In this study, calcium bentonite, natural sodium bentonites, and sodium activated bentonite were treated with the HYPER clay technique. This involves the adsorption of an anionic polymer, Sodium CarboxyMethylCellulose (Na-CMC) onto the surface of the clay material. The purpose of this research was to show the beneficial effect of the HYPER clay treatment on the swelling and hydraulic performance, while the bentonite is permeated with high concentration CaCl2 solutions. The test results showed that swelling and hydraulic performance increased with Na-CMC treatment, regardless of the type of bentonite that was used. Additionally, a powdered Na CMC configuration provided higher swelling and hydraulic performance compared to a granular configuration

Recent Geotechnical Developments in Geospatial Information Systems Technology

Geotechnical engineering projects in current research and practice are increasingly undergoing geospatial analysis based on geologic and geotechnical data collected. The explosion of spatial data that is available for surface features, particularly from the raster based products, heavily used by commercial and available to the public, present only one dimension of site characterization. Geotechnical engineers are more interested in data with depth immediately below their project site retrieve from drilled and imaged subsurface surveys. The ability to optimize the use of new and existing subsurface data continues to be undermined by the lack of a common and agreed data format and structure. Over the past decade several initiatives have tried to develop some consensus, with limited success. The latest initiative for a common geotechnical data exchange standard is also described. Several projects based on the authors, experience are featured in this paper and serve as examples of the challenge of working with large and diverse subsurface geotechnical databases. Additionally, an update of a geotechnical data exchange format is also presented to point the direction for the future

Specification of vertical semantic consistency rules of UML class diagram refinement using logical approach

Unified Modelling Language (UML) is the most popular modelling language use for software design in software development industries with a class diagram being the most frequently use diagram. Despite the popularity of UML, it is being affected by inconsistency problems of its diagrams at the same or different abstraction levels. Inconsistency in UML is mostly caused by existence of various views on the same system and sometimes leads to potentially conflicting system specifications. In general, syntactic consistency can be automatically checked and therefore is supported by current UML Computer-aided Software Engineering (CASE) tools. Semantic consistency problems, unlike syntactic consistency problems, there exists no specific method for specifying semantic consistency rules and constraints. Therefore, this research has specified twenty-four abstraction rules of class‟s relation semantic among any three related classes of a refined class diagram to semantically equivalent relations of two of the classes using a logical approach. This research has also formalized three vertical semantic consistency rules of a class diagram refinement identified by previous researchers using a logical approach and a set of formalized abstraction rules. The results were successfully evaluated using hotel management system and passenger list system case studies and were found to be reliable and efficient

Hydrological controls of in situ preservation of waterlogged archaeological deposits

Environmental change caused by urban development, land drainage, agriculture or climate change may result in accelerated decay of in situ archaeological remains. This paper reviews research into impacts of environmental change on hydrological processes of relevance to preservation of archaeological remains in situ. It compares work at rural sites with more complex urban environments. The research demonstrates that both the quantity and quality of data on preservation status, and hydrological and chemical parameters collected during routine archaeological surveys need to be improved. The work also demonstrates the necessity for any archaeological site to be placed within its topographic and geological context. In order to understand preservation potential fully, it is necessary to move away from studying the archaeological site as an isolated unit, since factors some distance away from the site of interest can be important for determining preservation. The paper reviews what is known about the hydrological factors of importance to archaeological preservation and recommends research that needs to be conducted so that archaeological risk can be more adequately predicted and mitigated. Any activity that changes either source pathways or the dominant water input may have an impact not just because of changes to the water balance or the water table, but because of changes to water chemistry. Therefore, efforts to manage threatened waterlogged environments must consider the chemical nature of the water input into the system. Clearer methods of assessing the degree to which buried archaeological sites can withstand changing hydrological conditions are needed, in addition to research which helps us understand what triggers decay and what controls thresholds of response for different sediments and types of artefact

Slope mainteannce [i.e. maintenance] and repair works in Hong Kong

Thesis (B.Sc)--University of Hong Kong, 2005.published_or_final_versio

Development of a GIS-based seismic hazard screening tool

Geotechnical earthquake engineering hazards have consequences that are difficult to mitigate, especially for infrastructure systems with multiple and distributed components. In the last few decades significant progress has been made to provide more accurate and useful methods to evaluate hazards for complex systems. One of these advances involves the application of spatial analysis and geographic information systems (GIS), for not only presenting data as maps, but also providing more practical and usable solutions, such as calculating the hazard potential with spatial distribution. This thesis studies the evaluation of geotechnical earthquake engineering hazards within a GIS environment, using borehole-specific data and seismic ground motions. Existing methods and applications used to evaluate these hazards, as well as existing geotechnical database formats are presented and discussed. This research developed a GIS methodology to be used as a screening tool: to evaluate geotechnical earthquake engineering hazards from a database of borehole data and then display the results on a map --Abstract, page iii

Network of European Research Infrastructures for Earthquake Risk Assessment and Mitigation(NERA)

The overall aim of NERA is to achieve a measurable improvement and a long-term impact in the assessment and reduction of the vulnerability of constructions and citizens to earthquakes. NERA will integrate the key research infrastructures in Europe to monitor earthquakes and assess their hazard and risk, and will combine expertise in observational and strong-motion seismology, modeling, geotechnical and earthquake engineering to develop activities to improve the use of infrastructures and facilitate the access to data. NERA will ensure the provision of high-quality services, including access to earthquake data and parameters and to hazard and risk products and tools. NERA will coordinate with other EC projects (SHARE, SYNER-G) a comprehensive dissemination effort. NERA will contribute to the OECD GEM program and to the EPOS ESFRI infrastructure.EU, Funded under :FP7-INFRASTRUCTURES-2010-