Conference Agenda

<p dir="ltr">Liquefaction is well known as an earthquake-induced hazard due to the build-up of the excess pore water pressure over and above the hydrostatic values and therefore result in the reduction of soil strength. This hazard has been responsible for tremendous damage in historical earthquakes which resulted in high economic losses and associated social costs. Some liquefaction countermeasures have been developed to prevent such damage, in which drainage method is one of the effective techniques. While using vertical drains, the principle objective is to relieve the excess pore water pressure generated during the earthquake before they reach high values that can finally cause damage and loss to infrastructures. However, most researchers focus on utilizing this method for new design constructures. As for existing buildings, sustainable and low-cost technique is also needed. On the other hand, gravel-tire chips mixture (GTCM) as an alternative drainage enhancing geomaterial, has been introduced recently. Previously studies on the properties of GTCM have addressed that with a suitable volumetric gravel fraction (50%-60%), the material could restrain the rise of excess pore water pressure without compromising the stiffness. Considering above, a new design of earthquake-induced liquefaction mitigation technique has been developed and described in this study. It utilizes GTCM as materials of drains installed vertically around the buildings. A series of 1-g model shaking table tests were conducted to evaluate the performance of the technique in this research. The results indicated that excess pore water pressure beneath the building was dissipated through GTCM drains effectively during the shaking. The liquefaction-induced settlement of the building was controlled to a significantly low level due to extra drains installed. GTCM drains show effectiveness in the reduction of liquefaction potential for both light and heavy buildings. </p>

<p>Especially in landfill lining systems at the bottom of a landfill and in mining, geosynthetic drainage systems are usually used at the base on a sealing system with geomembranes. The pollutants escaping from the waste or the precious metals extracted from the ores require, in addition to sealing, effective and rapid drainage of the leachate or the material released from the ore piles in mining. Especially in mining, the compressive loads on the sealing system and the overlying drainage system are enormous. They must be absorbed by the geosynthetic drainage systems without damage and without compromising hydraulic performance, i.e. enough water flow capacity.</p>

<p>Newly developed integrally manufactured geosynthetic drainage sheets (GDS) made of polyethylene (HDPE), which are based on a new, patented process, are being tested in laboratory trials to determine their compressive strength and water drainage capacity under extreme compressive stresses with soft bedding on specimens produced in the laboratory. The results of the novel GDS are also compared with laboratory-made geonet structures. While geocomposites with geonet drainage cores suffer very severe losses in water flow capacity under the influence of surcharge and even more so under the influence of soft bedding, drainage geocomposites made of the novel GDS show a much smaller decrease and better performance than conventional products.</p>

<p>Weaknesses of bi-planar geogrids with regard to pressure behaviour under the influence of compressive and shear forces as well as a reduction of hydraulic effectiveness with ribs running obliquely to the slope are specifically circumvented by appropriate selection and size of the waterway grooves of the GDS running in the machine and cross-machine direction.</p>

The swell-shrink behaviour of expansive soil causes excessive stresses to both rigid and flexible structures laid on them. The concept of reducing swelling potential and swelling pressure on ex-pansive soil by placing a compressible inclusion material such as EPS geofoam block is reason-ably well understood. To date, there are no previous studies available to understand the swell-shrink behaviour of expansive soils with the vertical inclusion of a compressible EPS geofoam granules column (GGC). This paper describes the performance of GGC in controlling the swell-shrink behaviour of expansive soil through laboratory studies. To study the cyclic swell-shrink behaviour, modified cyclic swell-shrink apparatus was developed to perform the wetting-drying cycles in the specimen under controlled laboratory conditions with and without GGC inclusion in expansive soil. The results of the experimental investigation were discussed in terms of re-duction volume change (i.e., swell-shrink) behaviour of expansive soils. Upon introducing an increased diameter of GGC, about half of the heave and shrinkage strain reduction was observed compared to plain soil (or soil alone, SA). This effect could be explained by soil-geofoam inter-action.

<p>Traffic loading and environmental factors such as temperature and moisture variations, are the main external causes of distresses evident in pavements, i.e., rutting, cracking, wear and deflection. Therefore, it is crucial to monitor pavement hydro, thermal and mechanical loading to facilitate operation, rehabilitation and maintenance of road networks. For this purpose, in-situ pavement monitoring methods are available, which use embedded sensors in the pavement to allow real-time supervision of the road health condition. Additionally, conducting traffic volume, vehicle mass and speed surveys is also important for effective traffic management and to prevent structural overloading of pavements. However, majority of such existing methods are destructive to the pavement while they can provide information at distinct locations only. Therefore, there is still a deficiency in a method that allows spatially continuous monitoring and retrieves complete information of vehicle loading in smart road infrastructure. In the current research, a novel graphene-coated geotextile is evaluated for use in applications involving hydro-thermo-mechanical loading, focused on its potential as a distributed sensor to detect pavement response and damage. Hence in this study, a series of tests were carried out to examine the piezoresistive response of the material by subjecting the geotextile specimens to tensile loading. The results showed a significant electro-mechanical behaviour in the graphene-based geotextile. The results also indicated that the graphene-based geotextile had potential to be used in a vast range of applications in road infrastructure, including the detection of excessive rutting and sinkholes. It is anticipated that the outcomes from this research will provide significant benefits towards developing tools and techniques for pavement monitoring and assessment and vehicle management of smart road infrastructure, using novel sensing materials.</p>

<p>Due to the limitations of the existing vertical anti-seepage technology, it was difficult to meet the requirements of environmental protection and anti-seepage. GCL composite vertical anti-seepage barrier technology introduces GCL into the field of vertical anti-seepage and combines with the low-permeability wall to form a composite anti-seepage structure. GCL was laid vertically along one or both sides of the excavated trench, and then the wall material was backfilled in the trench. The low-permeability wall can be conventional anti-seepage wall, and also can be designed as anti-fouling reaction walls according to specific pollutants. The low-permeability wall initially blocks the migration of pollutants, while GCL significantly improves the overall performance of anti-seepage. GCL composite vertical anti-seepage barrier technology is a composite anti-seepage structure, which can cope with complex polluted environments and solve the problems such as easy leakage at the joints and poor anti-seepage performance of conventional anti-seepage walls, et al. This technology has been applied in several projects of stock refuse treatment and pollution control. The engineering practice showed that the technology was simple in construction, permeability coefficient was less than 1×10^-7cm/s which could meet the requirements of environmental protection, and it was applicable for vertical anti-seepage projects with high requirements, such as landfill and polluted sites.</p>