No abstract

A Passive House (PH) system is not only an opportunity but also a necessity for the further development of sustainable eco-buildings. Construction of the foundation in energy-efficient houses is the key to maintaining low energy losses. The appropriate selection of building materials requires considering the thermal conditions of the environment, including its location and the zero isotherms in the ground. The main objective of this work is to analyze the possibilities of designing foundations for PHs in Poland, according to the current methodological data. In order to realize the basic aims, the work was divided into the following materials and methods: (I) literature review; (II) database of PH in Central Europe; (III) method of depth of ground freezing determination; (IV) selection of the joint of slab-on-ground foundation and external wall to analysis; (V) description and validation of the heat-transfer model. The result of the research work is: (i) analysis of the foundation under the conditions of freezing of the ground in Poland; (ii) description and validation of the heat-transfer model. The research has revealed that in the Polish climate zone, the most efficient solution for passive buildings is to build them on a foundation slab. The foundation of a building below the latest specified ground frost depths in Poland is inefficient in terms of, for example, thermal insulation, economics, and the idea of PH.

The article describes the proprietary modification of the standard triaxial cell which allows for the measurement of the transit S and P wave using only one pair of piezoelectric transducers, while it was possible to take into account or minimize some of the negative phenomena in the commonly used test procedures BET. The results of the tests for different types of soils were also presented.

The requirement for implementing local measurements at small strains is well known. Without this type of measurement, it is not possible to accurately identify the soil stiffness characteristics over the entire stiffness degradation curve. The paper presents the results of the use of new sensor based on miniature magnetic encoders for axial and radial deformation measurements in triaxial soil test. Presented results include two types of measurement techniques for radial direction and one for axial deformation.

The advantages of establishing databases of soil parameters are recognized within the geotechnical community. Especially, statistical description of soils is necessary tool for establishing probability distribution functions used in reliability based design framework and in standard deterministic approach of limit state design; previous knowledge, comparable experience, and engineering judgement, all play a major role in the selection process of characteristic values of most essential parameters. This is often done in face of limited amount of data from site investigation. The paper presents preliminary database compilation attempt for some parameters of overconsolidated glacial tills and clays from Poland. Due to a rapid growth of infrastructure and cities, analysis of already gathered data is essential for providing engineers with guidance on the variability of soil conditions, which is most noticeable in the case of fine‐grained overconsolidated strata. Focus is given to parameters obtained from triaxial laboratory tests, including small‐strain shear stiffness obtained from Bender Element Test.