PSI - Issue 62

Nicola Perilli et al. / Procedia Structural Integrity 62 (2024) 538–545 541 4 Nicola Perilli, Stefano Stacul, Massimiliano Lombardi, Nicola Nenci, Nunziante Squeglia / Structural Integrity Procedia 00 (2019) 000 – 000

2.2. Extent of the key areas: Relevant Area, Geomorphological Significative Area and Diagnostic Area The key areas described herein, and the suggested workflow (see next paragraph) will be useful to improve the performance of the technical staff involved in the assessment of landslide susceptibility, vulnerability, and exposure, during the desk study and the field work. Nevertheless, it is also necessary to define the areal extent and the shape of the key areas (Tab. 1). Based on the experience of the Authors, Table 1 suggests the criteria for the geometric definition of these areas in order to reduce their arbitrariness.

Table 1. Suggested dimension of the key areas: Diagnostic Area, Geomorphological Significative Area, and Relevant Area. A = total area, L up = upwards length; L down = downwards length; L bridge = bridge length; A up = upwards area; A down = downwards area

Key Area

Length of longest side (L)

Length of shorter sides (B)

Remarks

A includes two bands of equal area, as follows: (250 m + L bridge +250 m) x (250 m) (250 m + L bridge +250 m) x (250 m) parallel to the bridge A includes two bands of different area: A up = (2/3 L bridge + 350 m) x (250 m + L bridge + 250 m) A down = (1/3 L bridge + 150 m) x (250 m + L bridge + 250 m)

L is parallel to the bridge not located in a narrow valley

L = 250 m + L bridge +250 m

B includes two segments of 250 m

Relevant Area

L is perpendicular to the bridge located in a narrow valley

L = L up + L down L up = 2/3 L bridge + 350 m L down = 1/3 L bridge + 150 m

B = 250 m + L bridge + 250 m

Geomorphological Significative Area

ranges from 1 to 2 km

ranges from 1 to 2 km

Diagnostic Area

ranges from 2 to 5 km

ranges from 2 to 5 km

2.3. Workflow of the desk study and field work The evaluation of landslide susceptibility, vulnerability and exposure are difficult tasks that require careful desk study and field survey, which today are also supported by landslide susceptibility maps often obtained via remote images analysis. According to the LLG accurate geomorphological and geological field survey and in-situ testing (e.g. geophysical and penetrometric tests) are mainly foreseen during the so-called Special Inspections and/or Accurate Evaluations. The aim of Periodic Field Survey is twofold: (a) collect the information necessary to evaluate the primary and secondary parameters which contribute to the assessment of the main factors: susceptibility, vulnerability, and exposure; (b) the collection of the other data necessary for the characterization of the geomorphological and geological context and the identification and characterization of the outcropping materials, i.e. bedrock and/or engineering soil. Taking into account that: • the first text of the LLG was approved in 2020, • the experiences and skills acquired in their application including the data collection via the Field Sheet Form, are still ongoing and the achieved expertise are only partly shared between the different teams, • up to present the technical staff involved in the collection of the required data clusters, are often inexperienced and/or unskilled, the proposed workflow (Tab. 2), composed by the three tasks described in the following, is aimed to provide guidance to the desk study and field work necessary to fill the Field Sheet Form required by the LLG. Task 1 : this task is a back-office activity and consists in collecting the information about the geomorphology, geology, and land use of the Diagnostic Area, and in some cases of the Geomorphological Significative Area. Based on the documented characteristics of the Diagnostic and Geomorphological Significative Areas, this task is also