International - Special GeoArt: Conference on Geosynthetics

Geomembrane systems can be used for civil engineering purposes in watertight sealing of underground constructions. Since the early 70’s experience has been gained in The Netherlands with geomembrane systems in underground constructions for roads, rail- and waterways in open excavation pits. Due to the groundwater circumstances in the Dutch delta area most of the deep geomembrane systems are submerged, using PVC-p material (plasticized polyvinyl chloride). Submerging geomembranes (underwater installation) will require wide excavation dimensions. In urban areas most projects will have limited space. The dimensions of building pits can be limited in several ways, using some innovative design concepts. Construction concepts for use in limited space are the geomembrane U-polder and Sheet pile-polder. To prove the concepts several business cases and projects have been carried out. Geomembrane construction in limited space combines several known construction techniques like foundation works (sheet piles, anchoring), earth works, and submerging of geomembranes. The success of the concepts depends on a good understanding of design aspects, materials, risk-assessment and quality assurance during the building process. This article explains the concepts, trial testing and conditions for successful implementation of geomembrane systems with vertical boundaries in urban areas.

Piled embankments are used for road or railroad construction. They can speed up construction time in soft soil environments and reduce stability and deformation risks. A piled embankment consists of a field of piles on which an embankment of granular material is built. Basal reinforcement can be applied by placing geosynthetic reinforcement (GR) in the base of the embankment. The relatively stiff piles attract load from the embankment by means of arching (load part A). This lateral transport of load uses the friction of the granular fill. The load on the GR is partly carried to the piles through a tensile force in the GR (load part B), and partly carried by the subsoil (load part C).

This paper is based on the publication of Van der Peet and Van Eekelen (2014) and considers the distribution of the vertical load between arching (load part A, in kN/pile or A% in % of the total load) and the residual load parts B + C, in kN/pile. A comparison between numerical results and predictions of three analytical arching models leads to conclusions about the validity and accuracy of these analytical models.

Bridge decks expand and contract during a year due to temperature variations, as any other “non-restrained” structure. The amplitude of this movement depends on the type of bridge, its length and the climatic circumstances. There are several different types of bridge structures and an integral bridge is one of them. The most characteristic aspect of the integral bridge is the fact that the (continuous) concrete bridge deck only rests on steel bearing piles, concrete columns or a concrete wall. It is clear that given the relatively low rotational stiffness of these supports, as compared to the bridge “power”, a considerable thermal movement at the bridge ends needs to be taken into account, when designing the transition to the road pavement. This paper describes the development of a specific method to construct this transition without a visible and noticeable joint at the asphalt surface, and subsequently 11 years of field experience of the method, at several locations across the Netherlands.