Conference Agenda

Four laboratory models filled with aggregates with fractions 0-32 mm were prepared in a special laboratory box with dimensions of 1000x1000x600 mm. Three models were fitted with a geogrid, which, together with the aggregates, formed a mechanically stabilized layer (MSL), 100, 150 and 200 mm in thickness, while one model, without a geogrid, served as a reference model. A new-generation – multiaxial – geogrid was used for the experiments. The models were loaded with a static force of up to 100 kN with the aim of finding out the differences in the magnitude of lateral pressures acting on the laboratory box wall. The experiments revealed principal reductions in the horizontal pressures in the mechanically stabilized layer compared to unstabilized aggregates. The greatest reductions were recorded at the geogrid level, nevertheless, a significant reduction in horizontal pressures is manifested throughout the entire MSL. The intensity of the aggregate confinement in the geogrid is related to the reduction in horizontal pressures and quantified as a parameter enabling the evaluation of the efficiency of mechanical stabilization of aggregates by geogrids – the Confinement Efficiency Factor (CEF).

<p>Graphene, which is a dense two-dimensional structure of carbon atoms, is one of the lightest, thinnest, strongest, hardest, transparent and flexible materials discovered to date with respect to heat transfer, strength and electrical effects. Among them, by focusing on the electrical properties of graphene, the possibility of graphene applied in different fields such as display, batteries, and sensors are being actively in research. Studies in the civil engineering field focus on the ability to improve the tensile strength of graphene, and research to improve the structural ability of concrete is currently in progress. However, in this study, we intend to apply the electrical properties of graphene to concrete.</p>

<p>Concrete is nonconductive material. When the resistance value is measured by inserting a copper electrode into the specimen, it is approximately 4 killo-ohm or more. When this resistance value is calculated as a specific resistance(Resistivity, 1/conductivity) value, it is about 150 ohm-meter.</p>

<p>In this study, graphene oxide extracted from graphite was prepared. And graphene oxide was functionalized with copper ions. The functionalization assign electrical properties to graphene oxide with a rough surface. This copper-functionalized graphene oxide (Cu-GO) was mixed with concrete to give electrical properties to the concrete specimen.</p>

<p>The concrete specimen’s a resistance value of more than 4 kilo-ohms is about 1 kilo-ohm when graphene is mixed. As such, it was confirmed that the electrical conductivity of concrete improved more than twice when copper-functionalized graphene oxide was mixed.</p>

Recently, prefabricated vertical drains (PVDs) and deep cement mixing (DCM) columns have been combined to improve the soft soil ground under embankment. This not only significantly improves the shear strength in soft soil ground but also increases the rate of consolidation. The present study develops a simple two-dimensional (2-D) plane-strain numerical model of the DCM columns and PVDs improved soft ground under embankment. The geometry of the PVD and DCM column in equivalent 2-D model were obtained from the concept of same area replacement ratio, while the equivalent horizontal permeability of soft soil and DCM columns surrounding PVD was deduced from the matching of the total volume of water to be discharged in an axisymmetric model and the total changes in flow in a plane strain. Subsequently, the proposed method was applied to the Huai-Yan embankment in China, which was used the combined method for ground improvement. The results of settlement and lateral displacement obtained from the proposed model were good agreement with the observed data and results obtained from previous solution.

Two nonwoven geotextile tubes were installed at the Bela Vista Water Treatment Plant in Nova Odessa, Sao Paulo, Brazil, to receive sludge from the decanters monthly washing. The first geotextile tube had its filling cycles performed with fresh sludge, and the second, with the addition of flocculant polymer. The tubes were monitored during the filling and emptying cycles, and in the consolidation period, obtaining some hydraulic and mechanical characteristics. For hydraulics characteristics, the performance improvement was evaluated by applying flocculant polymer concerning the sludge dewatering and evolution of the solids content. Concerning the mechanical characteristics, the strains mobilized in the nonwoven geotextile were obtained and discussed.

Geotextile tubes are commonly used as shallow revetments, breakwaters and containment bunds in coastal protection structures. Most of them are in relatively shallow waters. A common installation method for these geotextile tubes involves dropping the filled geotextile tubes from split bottom hopper barges onto the seabed in a free-fall manner. However, this method may not be suitable in deep waters because of the lack of accuracy in its placement subjected to harsh waves and current conditions.

This paper critically evaluates an innovative installation method that can be done in deep waters (i.e. water depth 20-40m) that promise adequate placement accuracy, speedy installation, and cost effectiveness. This method makes use of a high-capacity floating crane barge can be used to lower fully filled geotextile tubes from a barge onto the seabed. A trial of the high-capacity crane method was conducted in Singapore to construct an underwater geotextile tube bund. Monitoring sensors such as strain gauges were installed on the geotextile tubes to monitor the effectiveness of this installation process. In addition, shape accelerometer arrays (SAA) were installed beneath the geotextile tubes to monitor the ground settlement and accuracy of installation process. Data from these sensors were analysed and discussed. Results and observations show that the high-capacity crane barge is an effective method for the installation of geotextile tubes in deep waters of 20-40m range.

An experimental study was conducted on the manifestation of organic contaminant-reactive geosynthetic liner for preventing the spread of contaminated groundwater. The polymer which has absorb oil highly and self-swelled was selected for the organic pollutant reactive geosyn-thetic barrier. This polymeric material has composited with nonwoven and film woven by nee-dle punching process as GCLs. The geosynthetic oil absent liner prepared was immersed in or-ganic pollutant material (TPH and TCE) for 24 hours and the permeability coefficient was evaluated (ASTM D5887). The permeability coefficient of the geosynthetic oil absent liner immersed in TPH and TCE was resulted in 7.3×10-8 cm/s and 1.1×10-8 cm/s, where the value of α×10-2 cm/s for the normal water as a control test. It was confirmed that the geosynthetic oil absent liner showed an orderly behavior that could sufficiently perform the role of a liquid bar-rier to prevents the spread of contaminated groundwater.

<p>A final cover system is the critical component of landfill closure. It isolates the underlying waste and prevents its exposure to the environment. The infiltration of stormwater into the waste is minimized and therefore, the leachate generation and associated treatment expenses are reduced. The selected closure option sets the bar for maintenance efforts and costs throughout the post‑closure period of a waste containment facility.</p>

<p>Recent years have seen a significant increase in the use of the innovative engineered turf cover to close municipal and industrial solid waste landfills. The engineered turf cover system consists of, from bottom to top, a structured geomembrane, an engineered turf, and a specified infill. By removing the soil layer in the final closure system, the engineered turf cover provides a reliable solution that overcomes long-standing challenges of soil erosion and geotechnical instability associated with traditional soil covers. Additionally, the site closed with the engineered turf cover becomes an excellent substrate for the development and production of renewable solar energy because overgrown vegetation or soil erosion is no longer a concern.</p>

<p>This paper provides an overview of this innovative landfill closure technology, including the engineered turf cover system components, functions, and installation procedures. A detailed comparison of the engineered turf cover with a traditional soil cover is presented with respect to stormwater runoff quality, final cover slope stability, environmental impact, post-closure maintenance, construction costs, and suitability for development of renewable solar energy. Case studies are presented to demonstrate the real-world performance of the engineered turf cover and show beneficial reuse of a facility closed with the engineered turf cover for solar power generation.</p>

<p>Electro-osmosis was discovered more than 200 years ago. Quite a lot of phenomena discovered in that early stage of research are still attractive up to now. It seemed that research on electro-osmosis had been suspended for a while since 1950s~1970s. It may be because both mechanism and engineering application of electro-osmosis are very complicated.</p>

<p>However, in the past decade, there were quite a lot of breakthroughs on electro-osmosis technique. One among those was Electrokinetic Geosynthetics (EKG), a new category of geosynthetics which provides corrosion proof electrode; another one was smart DC power supply. To some extent, these breakthroughs make large scale application of electro-osmosis possible. They tackle the challenge of power demand and energy consumption not only for electro-osmosis but also for all electrokinetic related techniques in geotechnical and geoenvironmental engineering and these techniques are still evolving.</p>

<p>This paper presents latest progresses on EKG and its application in large scale electro-osmotic dewatering and consolidation. Novel numerical modelling based on energy level gradient theory was carried out to model the field test of electro-osmotic consolidation using EKG. Comparison between calculated results and field test results is used for validation and further improvement of the numerical modelling program. The energy level gradient theory is a novel constitutive model that may help understanding of not only consolidation issue but also mechanism of unsaturated soil. Research presented in this paper is interdisciplinary and encouraging for further research.</p>