PSI - Issue 64

Emilia Damiano et al. / Procedia Structural Integrity 64 (2024) 1628–1635 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

1634

7

ε s ( με )

 v ( με )

-750 -500 -250 0 250 500 750

-750 -500 -250 0 250 500 750

0

0

NE

NE

100 300 500 700

NW

(c)

ε trad incl NE

5

5

SE

SW

10

10

ε s NE

M-23 S-23 M-24

15

15

-900 -700 -500 -300 -100 strain ( με)

20

20

z (m)

ε v

Compression

z (m)

Sliding zone

25

25

30

30

35

35

(a)

(b)

40

40

12/22

02/23

04/23

06/23

08/23

10/23

11/23

01/24

03/24

Fig. 4. DFOS-based inclinometer data collection: (a) vertical strain profiles and (b) horizontal strain profiles along the NE face of the tube; (c) trends of vertical and horizontal strain components and comparison with the one from standard inclinometer.

4. Conclusions The experimental investigations, carried out both in the laboratory and in the field, on a novel DFOS-based inclinometer highlighted that the new device has several potential advantages that, in a future perspective, might significantly steer stakeholders toward its use in monitoring slow-moving landslides that interact with structures and infrastructures. In this scenario, characterized by small changes in the strain field, the study demonstrated that after initial laboratory-based selection and calibration of the DFOS, equipping at least three faces of an inclinometer tube with the NSHT and a temperature cable enables individuation of the sliding surface and accurate measurement of strain changes over time. The new DFOS-based inclinometer allows separating the portion of strain induced by mechanical processes, such as consolidation/swelling or dilation/compression acting axially to the inclinometer casing, from those associated with sliding, providing further insights into slope kinematics. This represents an additional advantage of the innovative device, which can also act as a series of high-resolution extensometers, significantly overcoming the utility of the traditional device. Moreover, the use of NSHT, a specifically designed system for DFOS packaging, simplifies and standardizes installation procedures while protecting the DFOS from potential damage during installation. However, the widespread adoption of this promising technology in geotechnical applications is still hindered by the high cost of the analyzer and the requirement for preliminary DFOS laboratory calibration. Acknowledgments R esearch funded by 1) Università della Campania “L.Vanvitelli”, grant Program VALERE: “VAnviteLli pEr la RicErca”, DDG n. 516– 24/05/2018; 2) C.U.G.RI. Research Accord; 3) Italian Ministry of Economic Development #NOACRONYM Project, PoC MISE, 2021. Work developed within a C.U.G.RI. research assignment and a KTM research grant (University of Campania “L.Vanvitelli”) in the framework of Project VIRTU ( UTT PNRR 2023-2025). The authors acknowledge CARTFLOW for technical assistance and testing of the NSHT on the wind turbine wing.