MICROPILES TRIPODS SHIELDS (MTS) AS UNCONVENTIONAL BREAKERS FOR THE CONTROL OF MODERATELY RAPID EARTHFLOWS (SASSI NERI LANDSLIDE, NORTHERN APENNINES)

The paper deals with the idea, design and implementation of unconventional one-of-a-kind Micropiles Tripods Shields (MTS) intended to break and decelerate moderately rapid earthflows surges in the track zone of the Sassi Neri landslide (Nure Valley, Northern Apennines, Province of Piacenza, Italy). The MTS are inspired to floating anchors and “chevaux de fries” used in wartime. The basic elements are tripods of 193 mm diameter steel micropiles laid out at triangle, driven into the stable bedrock and emerging some meters aboveground. Each tripod consists of a vertical upslope central pile and two lateral oblique piles, linked by two transversal beams and connection plates aboveground. Multiple tripods are spaced along transversal rows to form Micropiles Tripods Shields (MTS) to advancing earthflows. The design of MTS has been based on field investigations such as boreholes and geophysics, that indicated a limited thickness of landslide deposits in the track zone where MTS have been installed. The forces resulting from active earthflows fronts have been estimated both with geotechnical and hydraulic computations. The analysis of vertical and transversal forces as well as bending moments acting on a single tripod versus the characteristic resistances was carried out using a bi-dimensional scheme with finite-elements software Plaxis, that indicated that the stress levels were compatible with the structural resistance of the tripods. The construction of MTS took place in 2018, involving working site preparation with partial lime-treatment of the surficial layers, underground micropiles drilling and installation, aboveground micropiles welding, tripods completion with connection beams and plates. Some tripods have been instrumented with load cells for monitoring earth pressures against micropiles, electric transducers for groundwater monitoring next to the piles, tiltmeters for tripods rotations and a total station for slope and tripods movements monitoring. Results show that the acceleration of slope movements corresponds to a generalized increase of pore water pressure at all the monitored tripods and to temporary slight tilting of the tripods which has so far being fully recovered when the landside slowed down and pressure decreased. This pioneering application indicates that once the characteristics of the earthflows are carefully considered, the depth to the bedrock in the installation zone is limited, and the logistical conditions in the field during construction are adequate, the MTS can be taken into consideration as a possible unconventional solution to break down and control moderately rapid earthflows

Debris flows in Val Parma and Val Baganza (northern Apennines) During the October 2014 alluvial event in Parma Province (Italy)

During the October 2014 alluvial event in Parma province, which also caused the city of Parma to be partially flooded, several debris flows affected the upper Val Parma and Val Baganza (northern Apennines, Italy) causing severe and widespread damages to check-dams, roads and other infrastructures. The meteorological event reached intensities as high as 80 mm/hour, which is well above the thresholds presented in literature for the alpine area. The result was the occurrence of tens of debris flow along the Mt. Cervellino - Mt. Vitello relief, which were triggered in zones of failure of slope debris coverage along the streams, remobilized and scoured debris along the track and destroyed several check dams and damaged roads that were overflown by debris. Since debris flows in the northern Apennines are considered quite rare events, their hazard is generally underestimated or overlooked. The event in the Parma province, at the opposite, warns against this potentially destructive events that, in a changing meteorological framework, might result much more frequent and widespread than expected also in the northern Apennines

Landslide Zoning Using the Principal Component Analysis on Monitoring Data: The Sauna Earth Slide\u2014Earth Flow (Parma, Italy)

In this contribute, we present the morphodynamic zoning of the Sauna complex earth slide\u2014earth flow (Corniglio municipality, Northern Apennines) obtained by integrating results of field surveys and of Principal Component Analysis (PCA) of continuous displacement monitoring data. Since January 2014, the area is surveyed by an Automated Total Station (ATS) monitoring 30 prisms with duty cycles of 2 h. An evacuation plan has been adopted by the local authorities, which is based on pre-defined movement thresholds. However, during more than 2 years of monitoring, the results have evidenced that in different zones of the slope, differentiate displacement rates and timings of response to precipitations take place. Therefore, in order to fine tune evacuation plans, movement thresholds should be more appropriately tailored on the basis of morphodynamic zones rather than being left spatially generic. The final result is a morphodynamic zonation of the slope that represents a useful document to identify areas in which differentiated movement thresholds can be assessed for alert and alarm

Processes and factors controlling the groundwater flow in a complex landslide: A case study in the northern Italy

The present work provides new insights on some factors controlling the groundwaterflow in low-permeability media affected by deep Apennine landslide, involving sev-eral million cubic meters of soil and rock. Rainfall and groundwater circulation areamong the major triggers of landslides. However, if the first factor is well studied,only few research deal with the hydrogeological processes in the landslide. Thus, inthis study, combined hydrogeological, geochemical and isotopic investigation wereperformed in order to: (1) characterize infiltration and flow processes and (2) under-stand the role of sliding surface on groundwater circulation in a complex landslidethat mainly involves sandstones and clay materials. Results indicate that at least twocircuits coexist: a faster one, where rainfall preferentially infiltrates and flows in awell-connected network of macropores, cracks and soil pipes, which mainly feeds thesprings; a slower and a deeper one that flows in the soil matrix and fractures of thelandslide body. Moreover, the investigated slip zones show an aquiclude characteris-tic in terms of groundwater circulation, where the flow is very slow and precipitationinfluence is negligible. These results could be helpful in an accurate slope stabilityconsiderations and to improve the reliability of landslide risk assessment

Hydrogeology, Hydrochemistry and Isotopic Investigation to Define the Lateral Hydraulic Boundaries of a Deep Rock Slide (Berceto Landslide: Northern Apennines)

The Berceto landslide is a deep and active rock slide located in the northern Apennines. It affects a slope characterised by the overlapping of flysch and shale formations. The landslide has been monitored since the 1990s and an inclinometer installed in the head zone shows a sliding surface at the depth of 110 m. The landslide and the adjacent areas are affected by morphological anomalies in the slopes and in the surface drainage patterns. These anomalies are related to the presence of deep landslide or to the presence of faults in the bedrock. In particular, the River Baganza (RB) is situated at about 100 m upstream of the landslide main scarp and it is separated from the landslide by a thin layer of shale. The RB streambed is located at an elevation 70 m higher than the elevation of the active sliding surface. Due to these morphological anomalies, it is possible to speculate that the present extension of the landslide limit is not correct and that the landslide sliding surface could be extended as far as the RB. In this study, hydro-chemical and isotopic investigation have been carried out on the Berceto rock slide in order to define the lateral hydraulic boundary, the geometry of the slide surface and the groundwater flow paths. The ion contents and the \u3b418O-\u3b42H values indicate the presence in the landslide body of an external source of groundwater which could be provided by the RB through a sliding surface developed within the shale or by the flysch below the landslide body

Safety and efficacy of COVID-19 vaccines in patients on dialysis: a multicentre cohort study in Italy

Background The aim of this study was to evaluate the efficacy and safety of COVID-19 vaccines in patients undergoing haemodialysis in Italy compared to the general population.Methods In this cohort study, 118 dialysis centres from 18 Italian Regions participated. Individuals older than 16 years on dialysis treatment for at least 3 months, who provided informed consent were included. We collected demographic and clinical information, as well as data on vaccination status, hospitalisations, access to intensive care units and adverse events. We calculated the incidence, hospitalisation, mortality, and fatality rates in the vaccinated dialysis cohort, adjusted for several covariates. The incidence rates of infection in the dialysis cohort and the general population were compared through Standardised Incidence Rate Ratio.Results The study included 6555 patients vaccinated against SARS-CoV-2 infection according to the schedule recommended in Italy. Between March 2021 and May 2022, there were 1096 cases of SARS-CoV-2 infection, with an incidence rate after completion of the three-dose vaccination cycle of 37.7 cases per 100 person-years. Compared to the general population, we observed a 14% reduction in the risk of infection for patients who received three vaccine doses (Standardised Incidence Rate Ratio: 0.86; 95% Confidence Interval: 0.81-0.91), whereas no statistically significant differences were found for COVID-19-related hospitalisations, intensive care unit admissions or death. No safety signals emerged from the reported adverse events.Conclusions The vaccination program against SARS-CoV-2 in the haemodialysis population showed an effectiveness and safety profile comparable to that seen in the general population