The mechanical behavior and the influence of compaction banding on the hydraulic properties in soft porous rocks were studied. The tested rock was Calcarenite Tuffeau de Maastricht. In the frame of experimental investigations, triaxial and oedometric tests were conducted under dry and drained conditions. The results demonstrated that the rock is forming discrete compaction bands under high confining stresses and steep angle shear bands under low confining stresses. Permeability measurements during the oedometric and triaxial compression tests under drained conditions demonstrated that the axial permeability decreases with increasing axial strain. The maximum permeability decrease was three orders of magnitude for 40% of axial strain.

Although stone columns have been frequently used for the prevention of soil liquefaction in the last few years, their mechanical performance is still not fully understood. Both numerical calculations with conventional constitutive models and small-scale laboratory experiments do not explain the improving mechanisms satisfactorily. Under seismic effects, the interaction between the soil and the columns, especially between the pore water and the soil skeleton, makes the understanding of this method even more difficult. In this paper, an application of stone columns for the prevention of soil liquefaction is numerically investigated by means of 2D and 3D simulations. A hypoplastic model was used for the soil description. The drainage effect of the columns and their contribution to the stiffening of the ground were considered separately. Furthermore, the impact of the columns installation method was investigated by increasing soil density and stress ratio. Finally, the role of the intensity of the dynamic load was studied.

Although the fundamental scientific understanding of the relations between design, material, process, and product in additive manufacturing with concrete is already being explored, the relevance of this construction method for architecture and building is still limited. Additive manufacturing holds the promise that any computer-generated geometry can be produced. However, especially FDM-based processes are currently limited by geometrical and material-related restrictions. This study reflects on the digital workflow between architectural design, the geometry, and numeric data produced, construction processes and the material parameters in the research project “BauProAddi” on additive manufacturing with concrete. The purpose of the research is to integrate the knowledge of material and process specialists and requirements of the building industry at an early stage of the design process in a workflow for on-site additive manufacturing.

Three-dimensional printing – often known as additive manufacturing or the layered production of 3D objects – has been the focus of attention in the media at present and a subject that arouses great expectations in the construction industry. While the topic is rapidly emerging, 3D printing has the potential of simplifying key processes in the facility lifecycle, for example, by following design to production principles and reducing waste while increasing the quality of the final product. A pivotal piece in the success of 3D printing in construction is the Building Information Modeling (BIM) method. Since BIM already serves as a rich source of geometric information for commercially-existing, large scale, and automated 3D printing machines, 3D printing robots co-existing with human workers on construction sites will eventually need scheduling and assembly sequence information as well to maintain safety and productivity. As suitable 3D printing techniques and materials are still parts of wider research efforts, applications by early adopters in the construction industry demonstrate how 3D printing may benefit and at some point in the future complement existing construction methods like prefabrication or modularization.

Secondary settlements in soft soils represent a significant fraction of the total settlement induced by external loads. Consequently, these settlements can play a key role in performance, serviceability, and safety of engineering works such as buildings, roads, embankments, and pipelines. This paper addresses the development of a predictive settlement model for a railway embankment built on soft clayey–peaty soils by following an original procedure consisting of three cascading steps: (i) preliminary detection of the most settlement-affected portions of the infrastructure; (ii) development of an equivalent subsoil model to study secondary settlements; (iii) back-calculation of the parameters of a predictive settlement model (design subsoil model) via a variational data assimilation scheme that exploits ground displacement measurements derived from differential interferometric synthetic aperture radar (DInSAR) data. The main achievement relies on the retrieval of a stochastic prediction of secondary settlements that can contribute to rationalize both conventional monitoring campaigns and management of key infrastructure.

Presently near surface geothermal energy already covers an essential part of the German base-load capacity in the heat sector. Thermal activation of tunnels represents an interesting alternative and could be an economically useful solution which is complementary to the presently applied hybrid systems in ground engineering. The utilization of heat fluxes from the subsoil and from the tunnels themselves is an essential difference between tunnel absorbers and activated piles as well as diaphragm walls; therefore the utilization of tunnel absorbers can be regarded as a duo-hybrid-system. Two tunnel geothermal plants - Stuttgart–Fasanenhof and Jenbach - have provided reliable data on the subsoil, tunnel lining and tunnel air temperatures for the last four years. This data gives the basis for the research activities of the University of Stuttgart. This article concentrates on the geothermal test plant Stuttgart–Fasanenhof; describes the general setup of the subsoil absorber equipment, the geological and hydrogeological conditions and the operation periods. Furthermore, measurement results as well as possible energy extraction rates will be discussed. The tunnel air temperature is essential for the heat flux density towards the tunnel. An approximate formula to estimate this temperature is described in this article.

Hydrogen sulfide (H2S) is a critical component of biogas formed under anaerobic conditions by sulfur and sulfate reducing bacteria from animal manure and renewable energy crops. H2S causes high corrosion in equipment, has a negative environmental impact, inhibits the biogas formation process and is furthermore odorous and toxic. Although several methods for internal and external desulfurization found their way into practice and had been explored at laboratory scale, no data were available on the performance of such methods in full scale practice, especially for an external fixed-bed trickling bioreactor (FBTB). The effects of temperature, pH and air ratio on H2S removal efficiency (RE) were studied. The study was conducted at a research biogas plant with a given output of 96 m3 biogas per hour, and an H2S concentration ranging between 500 ppm and 600 ppm (1 ppm=1 cm3/m3) on average. The FBTB column has been designed to hold a packing volume of 2.21 m3 at a gas retention time of 84 seconds being loaded at an average of 32.88 g H2S/(m3?h). The highest H2S RE of 98% was found at temperatures between 30

The case history is located in southern Germany at Lake Constance. The construction work for the 5-storey building with a length of 87.5 m and a width between 17.5 and 22.5 m began in the summer of 2007. A site plan of the excavation is shown in Figure 1.