PSI - Issue 84

Marco Barla et al. / Procedia Structural Integrity 84 (2026) 441–448

444

inspections, in 2024, a structural and geotechnical monitoring system was installed on the slope, and monitoring data revealed accelerated deformation trends, particularly between 21 and 26 October 2024, following intense rainfall events. These observations prompted the motorway concessionaire to modify the original planned schedule for the new retaining works and the designer to implement, under emergency conditions, the early execution of selected structural mitigation measures. The level of criticality associated with this situation required, during both the planning and execution phases, the adoption of an integrated approach combining construction activities, detailed monitoring, and advanced numerical modelling to verify stability conditions throughout all transitional construction stages. This paper illustrates how the implementation of this approach enabled the planning, organization, and execution of the works without disruption to motorway traffic and without compromising worker safety. The slope stabilization scheme consists of the following multi-stage intervention (see Fig. 3): 1. construction of a ~3.5 m high compacted earth embankment adjacent to the roadside pile wall, supported by lightweight concrete blocks; 2. excavation of the slope sector previously supported by anchored concrete slabs (activity A); 3. installation of a micropile wall to support excavation and removal of the upper anchored slabs (activity B); 4. addition of active anchors on the existing roadside pile wall (activity C); 5. installation of passive anchors on the top of the micropile wall (activity D+E+G); 6. phased excavation of the slope behind the upper anchored slab, including its demolition (activity F+H+K+J); 7. construction of an additional anchored micropile wall in the slope sector between the upper and lower former concrete slabs; 8. construction of a permanent reinforced concrete retaining wall, underpinned by micropiles and stabilized by two rows of active anchors, adjacent to the upper micropile wall; 9. phased excavation (three stages) and demolition of the lower anchored concrete slabs; 10. construction of a second anchored reinforced concrete retaining wall, adjacent to the lower micropile wall; 11. slope regrading and soil nailing on the lower slope to reduce the final average inclination; 12. installation of sub-horizontal drains in the slope sector behind the new retaining wall; 13. removal of the temporary embankment below the roadside pile wall; 14. construction of a permanent reinforced concrete wall along the full height of the roadside pile wall, anchored by two rows of active anchors. •

Fig. 3. Multi-stage slope stabilization system.