Increasing use of the ground as a thermal reservoir is expected in the near future. Shallow geothermal energy (SGE) systems have proved to be sustainable alternative solutions for buildings and infrastructure conditioning in many areas across the globe in the past decades. Recently novel solutions, including energy geostructures, where SGE systems are coupled with foundation heat exchangers, have also been developed. The performance of these systems is dependent on a series of factors, among which the thermal properties of the soil play a major role. The purpose of this paper is to present, in an integrated manner, the main methods and procedures to assess ground thermal properties for SGE systems and to carry out a critical review of the methods. In particular, laboratory testing through either steady-state or transient methods are discussed and a new synthesis comparing results for different techniques is presented. In situ testing including all variations of the thermal response test is presented in detail, including a first comparison between new and traditional approaches. The issue of different scales between laboratory and in situ measurements is then analysed in detail. Finally, the thermo-hydro-mechanical behaviour of soil is introduced and discussed. These coupled processes are important for confirming the structural integrity of energy geostructures, but routine methods for parameter determination are still lacking.

The use of geotextile filters has been a common application in geo-environmental and geotechnical engineering for decades. The purpose of the present paper is to assess the influence of artificial physical clogging and cyclic water flow on the water permeability characteristics of nonwoven geotextiles used commonly in filter and drainage systems. Despite many studies examining the behavior of soil-geosynthetics, the mechanism of physical clogging is not fully understood yet and remains incompletely defined. Artificial clogging and cyclic water flow tests have been conducted according to a procedure created by the authors. Three nonwoven geotextiles and silty sand were employed in the test series. Hydraulic properties of the tested geosynthetics were determined according to the ISO standard. Filter design criteria are also discussed. The paper also presents the changes of water permeability characteristics due to clogging and cyclic water flow. The results show significant decrease of water permeability coefficients of the tested nonwoven geotextiles after artificial clogging and under cyclic water flow. Furthermore, the clogging mechanism was observed and confirmed by three-dimensional computed tomography.

Secondary raw materials (SRMs) tend to be a valuable replacement for finite virgin materials especially since construction works (i.e., building and civil engineering work such as road construction) require vast quantities of raw materials. Using SRM originating from recycling a broad range of inorganic waste materials (e.g., mining waste, different industrial wastes, construction, and demolition waste) has been recognized as a promising, generally more cost-efficient, and environmentally friendly alternative to the exploitation of natural resources. Despite the benefits of using SRM, several challenges need to be addressed before using SRM even more. One of them is the long-term durability and little-known response of construction works built using such alternative materials. In this paper, we present the activities to establish a fully functioning digital twin (DT) of a road constructed using SRM. The first part of the paper is devoted to the theoretical justification of efforts and ways of establishing the monitoring systems, followed by a DT case study where an integrated data environment synthesizing a Building Information Model and monitored data is presented. Although the paper builds upon a small scale, the case study is methodologically designed to allow parallels to be drawn with much larger construction projects.

Shallow geothermal energy systems (SGES) may take different forms and have recently taken considerable attention due to energy geo-structures (EGS) resulting from the integration of heat exchange elements in geotechnical structures. Still, there is a lack of systematic design guidelines of SGES. Hence, in order to contribute towards that direction, the current study aims at reviewing the available SGES modeling options along with their various aspects and practices. This is done by first presenting the main analytical and numerical models and methods related to the thermal behavior of SGES. Then, the most important supplementary factors affecting such modeling are discussed. These include: (i) the boundary conditions, in the form of temperature variation or heat flow, that majorly affect the predicted thermal behavior of SGES; (ii) the spatial dimensions that may be crucial when relaxing the infinite length assumption for short heat exchangers such as energy piles (EP); (iii) the determination of SGES parameters that may need employing specific techniques to overcome practical difficulties; (iv) a short-term vs. long-term analysis depending on the thermal storage characteristics of GHE of different sizes; (v) the influence of groundwater that can have a moderating effect on fluid temperatures in both heating and cooling modes. Subsequently, thermo-mechanical interactions modeling issues are addressed that may be crucial in EGS that exhibit a dual functioning of heat exchangers and structural elements. Finally, a quite lengthy overview of the main software tools related to thermal and thermo-hydro-mechanical analysis of SGES that may be useful for practical applications is given. A unified software package incorporating all related features of all SGES may be a future aim.

The railway infrastructure is a very important component of the world’s total transportation network. Investment in its construction and maintenance is therefore significant on a global scale. Up to now, some results of the life-cycle assessment (LCA) of open railway line, as well as railway bridges and tunnels, have been published, but detailed analyses of transition zones have not so far been performed. In railway networks, transitional zones are a critical area where the transition from open rail to solid bridge construction can cause significant settlements. The goal of these analyses was to compare two different types of track renewal methods for railway transition zones. In the first method, traditional cement stabilisation is used, whereas the second solution makes use of a geocomposite anchored by steel anchors. The paper presents some results from an environmental study for railway transition zones based on the demonstration case. The results of the performed LCA showed that, in the case of track renewal for transition zones by means of a geocomposite and anchors, the environmental impact is lower than in the case when cement stabilisation works are performed. Less extensive excavation works and thus lower quantities of used material are additional benefits.