Landslides represent a significant hazard for pipelines because they can generate permanent ground displacement and tend to result in complete failure or significant leaks, major environmental impacts and long periods of service disruption. Hence, landslide-related incidents are regarded as a significant operational risk. The paper mainly focuses on the assessment of landslide hazard along or across a natural gas pipeline project and on the identification of these hazards, mostly in the field. Whether the “expected” landslide event reaches the Right of Way (RoW) and impacts the pipeline, is influenced by the nature and size of the expected landslide event, controlled by the site geology and geomorphology, the proximity of the existing landslide feature to the pipeline and the position of the pipeline relative to the landslide. Landslide hazard assessment is used to identify “hot spots” along the pipeline route where re-routing or risk reduction measures must be prioritised. When landslides that can threat the pipeline integrity cannot be avoided, more detailed site evaluation is required to support the design and construction of mitigation measures.

The Holy Monastery of Panagia Spiliani is an important religious monument of the Aegean islands. The monastery is built on a steep rocky hill in the Castle of Mandraki on Nisyros island. On the slopes of the foundation area of the monastery, landslides have occurred in the past, mainly rockfalls and slides, while the risk of new similar phenomena in the future is high. To assist the geohazard assessment and mitigation design works, a combined survey using Terrestrial Laser Scanning (TLS) and Unmanned Aerial Vehicle (UAV) photogrammetry was implemented. Besides capturing the detailed morphology within high-resolution 3D point clouds, the main engineering geological units were identified on the slopes, while critical structural ground elements and unstable blocks were mapped in detail. These were quantified in terms of geotechnical parameters, and the engineering geological model of the hill was finalised and presented in an engineering geological map and cross sections. The mitigation measures are targeted towards the stabilisation of the wider area of the upper slope, hence the stability of the monastery and its surroundings risk elements, as well as the support of specific, large- to small-scale unstable rock blocks on the whole slope area, securing accessibility to the main beach of the village.

Underground monument preservation is tightly linked to geological risk. The geological risk management of underground structures typically relies on a preliminary site investigation phase. Engineering geological mapping—as a key site investigation element—is largely based on manual in situ work, often in harsh and dangerous environments. However, although new technologies can, in many cases, decrease the on-field time as well as eliminate inaccessibility issues, the example presented in this study demonstrates a special challenge that had to be addressed. The ancient underground marble quarries of Paros Island in Greece constitute a gallery complex of a total length of 7 km and only two portals, resulting in total darkness throughout almost the full length of the unsurveyed galleries. As such, the entire survey and engineering geological mapping solely relied on a virtual reality application that was developed based on a digital replica of the quarries using laser scanning. The study identifies several critical locations with potentially unstable geologic structures and computes their geometrical properties. Further numerical analyses based on data extracted directly from the digital replica of the rock mass led to the definition of appropriate risk mitigation measures along the underground marble quarries.

This study focuses on the geotechnical evaluation of the foundation conditions of the Agrippa Monument at the Acropolis of Athens, aiming to propose interventions to improve stability and reduce associated risks. The assessment reveals highly uneven foundation conditions beneath the monument. A thorough collection of bibliographic references and geotechnical surveys was conducted, classifying geomaterials into engineering-geological units and evaluating critical parameters for geotechnical design. Geotechnical models were developed and 3D finite element analyses were performed. The qualitative evaluation of the foundation under static conditions indicates no immediate risk of failure, as no accelerated movement has been observed and the monument’s tilt remains well below critical values. Time-dependent settlements are not expected from any clay layers in the artificial fills. However, further soil compaction could occur due to seismic events, water action (causing erosion or voids), or changes in the monument’s weight or tilt under static conditions. The study also proposes instrumental monitoring, foundation soil improvement, and water management strategies to enhance the monument’s stability and mitigate potential risks.

The Thessaloniki Metropolitan Railway comprises two separate ~6 m diameter parallel tunnels with an ~8 km stretch each and 13 stations. The geology of the urban area of Thessaloniki is characterised by the presence of Neogene and Quaternary deposits. The base formation for the project area is a very stiff to hard red clay, dating to Upper Miocene-Pliocene. Upon this formation, Quaternary sediments have been deposited, most of which comprise sand and/or gravel in a clay-silt dominated matrix, covered in places by anthropogenic fill. Ground investigation campaigns incorporated a significant number of sampling boreholes and in situ and laboratory testing. This information was elaborated in order to obtain a better geological understanding and a geotechnical zonation of the ground with respect to mechanized tunnelling. EPB M appears to be the reasonable choice for the project in all aspects of tunnel safety and tunnelling performance. The characteristics and parameters of the soils and the hydrogeological regime directed towards this selection and it is expected that all the objectives, such as settlement and ground movements control, water table level maintenance and adequate performance, will be met by an EPBM provided it is properly operated