Conference Agenda

<p>Retaining structures are one of the most common applications of geogrid-reinforced soil. Most design approaches (British Standard BS 8006, German Standard DIN 4017, EBGEO) assume a multi-body mechanism below a quasi-monolithically reinforced block for bearing capacity failure. In previous small-scale model tests, it was observed that these assumptions are well justified and that the experimental load-bearing capacity exceeds that of analytical equations according to standards mentioned above, but that it may be overconservative. In order to verify these results, which might be influenced by scale-effects, large-scale tests are presented in this paper using regular geogrids and practice-related wall specifications. A 1.5 m high and 1.0 m wide geogrid-reinforced wall with a wrapped-around facing is installed on 2.0 m loose sand as subsoil. Then a vertical load was applied on top of the reinforced structure. Horizontal and vertical wall deformations were recorded with several LVDTs and the kinematic behaviour of the wall footprint at the bottom reinforcing layer was observed through a transparent side window using digital image correlation (DIC). Additionally, geogrid strains and soil stresses were measured within the structure during bearing capacity failure. Finally, the experimental data are compared to the results of analytical bearing capacity equations. In further studies, these large-scale tests serve as a benchmark for numerical modelling.</p>

<p>Reinforced soil retaining wall (RSW) were regularly inspected for safety at least twice a year, However, collapse accidents frequently occur due to various causes such as drainage problems owing to heavy rainfall and increase in earth pressure owing to surface load. In addition, collapse accidents occur unexpectedly, such as collapse even if it is inspected as safe. Therefore, we need technology that can continuously monitor the behavior of the retaining wall.</p>

<p>In general, since a depth image between an image and an object cannot be extracted from an image taken from a single viewpoint, it is not possible to accurately analyze the three-dimensional behavior of the real space. However, based on the collapse mechanism of the reinforced soil retaining wall, the behavior of the reinforced soil retaining wall is defined as facing displacement and settlement. Therefore, even if there is no depth image, it is possible to accurately analyze the actual behavior by using the amount of x and y change in the image taken at a single point of view. CNN and feature matching were applied to track the reinforced soil retaining wall block before and after the occurrence of the behavior, and block registration error (BRE) was applied based on the coordinates of each vertex of the existing block and the matched block to evaluate the block matching performance.</p>

<p>The amount of change (d_xi,d_yi) in the image calculated through this was applied to the behavior calculation algorithm to calculate the actual behavior (d_xr, d_yr). The behavior evaluation performance was evaluated based on the error comparing the reference displacement and calculated displacement obtained by generating the behavior of the reinforced soil retaining wall through laboratory experiments, and the applicability was evaluated by applying the technology to the actual reinforced soil retaining wall.</p>

<p>In many cases, the foundations of structures are constructed near the edge of slopes, which may bring about a lack of bearing capacity. In recent years, several studies have been carried out on the application of geocell reinforcement in enhancing the global stability of slopes. However, there are limited studies on the effect of geocell reinforcement in slope stability when the reinforced slope is subjected to footing loadings. In this study, the positive impacts of geocell reinforcement on the bearing capacity of strip footings on slopes are discussed. Also, a parametric study has been conducted to investigate the effect of the reinforcement on the potential slip surfaces and factors of safety. The results of the experimental study indicate that the load-settlement behavior and bearing capacity of the strip footing can be considerably enhanced when the geocell layer is located at the appropriate depth in the slope. The parametric study shows that geocell reinforcements were found to be advantageous in increasing the factor of the safety of the slopes due to intersecting the failure planes and forcing them deeper into the underlying soil.</p>

In this modern era, installation of geosynthetics is an effective and economical way to cater this soil stability problem. It also helps in designing the reliable, constructible, eco-friendly, cost-effective geotech structures. In this study mechanically stabilized earth wall reinforced with geogrids and wire mesh is analyzed. Numerous infrastructures resting on embankment may get failure due to collapse which may result in financial loss, loss of life and disturbance in the services which may take few years to rebuilt. The effect of geogrid and wire mesh as soil reinforcement were studied in this study. To assess the performance of the reinforced fill structure, finite element method was adopted with the use of geogrid and wire mesh as reinforcing element. The geometry model of this reinforced fill structure is 10m height, 20m wide. The axial stiffness of geogrid, EA = 3000 kN/m has been used in the model, type of geogrid used consist of high tenacity polyester fibers coated with a polyethylene sheath. The factor of safety after using geogrid & wire mesh was to check the for stability of the structure. It was observed that with the use of geogrid & wire mesh, the displacement parameters were directed towards the stability of the reinforced fill structure. The study will help to evaluate the effectiveness of geogrid & wire mesh as reinforcing unit.

<p>The geological structure of the area determines the type of reinforcement technology to be used. Before choosing the type of geosynthetic for soft soil or embankment reinforcement the availability of aggregates in the area of the Investment should be considered.</p>

<p>Polyester geotextiles are materials with very high mechanical parameters, durability and relatively low elongation at break, which allows them to be used even in heavily loaded structures.</p>

<p>The author presents the implementation of civil engineering applications in which polyester geotextiles were used to improve the bearing capacity of the subsoil and to ensure the stability of the embankments.</p>

<p>The choice of this type of solution was economically justified due to the availability natural sand and gravel aggregate in most part of Poland. The case study analysis will provide evidence of advantages of using polyester geotextiles solution in civil engineering.</p>

<p>The paper refers to one of the largest reinforced soil walls project in Europe, the Bar-Boljari Highway construction project in Montenegro, whose contract was awarded to Road and Bridge Corporation (CRBC) Montenegro Branch. The highway runs on hilly terrain with high slopes, hence for a large part the soil has to be excavated upslope, while for the valley side high embankments have to be built to support the road. In order to minimize the height of the embankments, to minimize land occupancy, and to minimize the quantity of excavation at the toe and the quantity of required fill, the valley side was supported by reinforced soil walls, with height up to 38 m. Segmental wall with uniaxial extruded geogrids connected by special connectors to small size precast concrete blocks for facing has been selected as the technology for this impressive project. The reinforced soil structures have been analyzed and designed under static and seismic conditions with reference to EuroCodes and Italian Norms for Construction. The design process included Internal stability, External stability, and Global stability analyses, plus miscellaneous considerations, including wall facing details and external drainage. Due to the type of facing and reinforcement, the shear strength analysis of concrete blocks and the pullout analysis at the connection between geogrids and concrete blocks were carried out. For serviceability conditions the horizontal displacements for the walls were analysed, for which a model for obtaining the horizontal displacements of reinforced soil walls directly from the results of LEM calculations in SLS conditions was used. The paper presents the overall reinforced soil walls project, the design of the walls in static and seismic conditions, the horizontal displacement analysis, and the construction method, with details of the most challenging situations.</p>

<p>Kandy, a UNESCO World Heritage Site, is the second largest city in Sri Lanka. The city lies on the ‘Kandy’ plateau which is mountainous and thickly forested. With the develop-ment and population growth in Kandy, it is necessary to construct a wastewater treatment plant which include sludge drying beds. The sludge drying beds which occupy area of about 1.5 acres located in a hilly area on the outskirts of Kandy, namely Gohagoda. To provide the necessary flat platform areas and access road, 250 m length of reinforced soil slopes with slope angle of 65° was constructed on site. The reinforced soil slopes com-prise of single tier and two tiers slope with maximum height of 18 m, consisting of gabion facing units with layers of composite reinforcement geotextile. Total 44,000 m2 of high tenacity composite reinforcement geotextile with characteristic ultimate tensile strength up to 100 kN/m were used in the project.</p>

<p>Construction of yacht hangars in Prymorskyi (Crimea, Ukraine) led to the need to prune the existing Black Sea coastal slopes. It required additional measures to stabilize the technogenic slopes, which were formed as a result of pruning. There was no necessary space to make the slopes gentle (the need to locate the hangars in the coastal zone), so it was recommended to use geotextiles to reinforce them. The PLAXIS software package and the simplified LANDSLIP program with the Bishop and Spencer model were used. The initial slope had been stable for many years before pruning. The PLAXIS program allowed to perform direct dynamic calculations of the initial and pruned slopes. Calculated accelerograms of earthquakes of 7 and 8 points, which may take place in the area of the construction site in the future, were used for calculations. The height of pruning the natural slope along these sections would be the largest (6-7 m). In view of this, further direct dynamic calculations of the coefficient of stability of the technogenic slope reinforced with synthetic materials were performed for the section 4-4. According to the updated calculations in the PLAXIS software package, the required breaking strength is provided by geotextile materials with a density of 130-170 g/m². Reinforcement of the technogenic slope with synthetic materials should be carried out in layers every 0.75 m using backfilling with binding soil from pruning the slope with a specific gravity of 1.91 tons per m³without compression, as the backfill soil will be compressed during construction under the weight of the above placed reinforced layers. Reinforcement of the backfill must be carried out to the level of 1 meter below the design marks of the earth. The length of laying synthetic materials in the slope should be at least 2 m.</p>

<p>Using geogrids to anchor sheet pile walls (SPWs) is a relative new application of geogrids. The construction method has similarities with reinforced soil-retaining walls with a full-height rigid facing. Differences are that the facing of the SPW is embedded in the ground and that generally more layers of geogrid are applied in reinforced soil. This paper compares medium scale experiments on both structure types, that were conducted at the Deltares laboratory in the Netherlands and at the Ghent University in Belgium respectively, using the same test-box. In all experiments, a strip footing surcharge load was applied. The experiments were simulated using 2D Plaxis. For both structures, the experiments and the numerical analyses showed how two slip surfaces develop, starting at the edges of the strip footing. The paper analyses the differences and similarities in the slip surfaces and the bearing capacity between the two construction types in detail.</p>