Presentació realitzada per Giovanni Gigli i Emanuele Intrieri (Università Degli Studi Firenze) a la jornada sobre monitorització del terreny com a eina de gestió del risc i presentació del Projecte Europeu Wi-GIM (27/01/2017)

1. Results and future of Wi-
GIM
E. Intrieri, G. Gigli, L. Lombardi, M.
Nocentini, T. Gracchi, N. Casagli

2. 2
Design criteria
•Emergency monitoring
•Low cost
•Fast installation

3. 3
Wireless
Sensor
Network
Ranging

4. 4

5. 5
Rapid installation
Autonomy
Low cost
Modularity
Real time (EW)
Re-adaptability
Low vulnerability
High deformations Low environmental impact
Versatility
24 h

6. 6
Stress tests

7. 7

8. 8
2.56 m
66.36 m

9. 9
2.56 m
66.36 m
No relation with the distance was observed

10. 10
3.30 m
On 20/12 the obstacle
was removed:
- Increased accuracy
- Precision unaffected
With obstacle
Without obstacle

11. 11

12. Roncovetro test
site
Photo by G. Bertolini
• Emilia-Romagna (Italy)
• 2.5 km long mudflow
• Average velocity of a few
decameters per year
• Velocity up to 10 m/day
• 3·106 m3 volume

13. 13
2001 2014

14. 14
Propedeutical
monitoring

15. 15
Propedeutical
monitoring

16. 16
Propedeutical
monitoring

17. 17
Propedeutical
monitoring

18. 18
Wi-GIM
installation

19. 19
Cluster 1

20. 20
Nodes distance

21. 21
Cluster 2

22. 22
Nodes distance

23. 23
Raw data

24. 24
Cluster 1
Measurements made

25. 25
Cluster 1
Valid measurements

26. 26
Cluster 2
Measurements made

27. 27
Cluster 2
Valid measurements

28. 28
Meteorological
conditions

29. 29
Raw data
X: distance between 3 and 7
O: distance between 7 and 3

30. 30
Valid
measurements

31. 31
Corrected
measurements

32. 32
Daily averages

33. 33
X: Wi-GIM data
O: RTS data
Data
validation

34. 34
X: Wi-GIM data
O: RTS data
Data
validation

35. 35
Data
validation
X: Wi-GIM data
O: RTS data

36. 36
Node 10

37. 37
Data validation
X: Wi-GIM data
O: RTS data

38. 38
Data validation
X: Wi-GIM data
O: RTS data

39. 39
Cluster 1
Wireless extensometer

40. 40
Motion tracking

41. 41
Cluster 2 – Node 12
Motion tracking

42. Sallent test site
42
• Catanulya (Spain)
• Old underground potash
mine
• 40 m large 110 m high
natural cavity
• 50 cm vertical subsidence
between 1997 and 2010

43. 43
Google Earth photo 2006 Google Earth photo 2015

44. 44
Master Node UWB Master node with CW Radar

45. 45
X: distance between 1 and 5
O: distance between 5 and 1
Monitoring data
Making 1 measurement every
6 hours 4x2 readings are
obtained which can be
averaged to obtain 8 cm
precision.

46. Wi-GIM Results
46
Wi-GIM results
First results of Wi-GIM show raw measurement
accuracy of about 8 to 30 cm depending the
sensor location. Due the nature of subsidence
dynamics (small and slow but sustained in time),
this accuracy implies that this monitoring system
needs some time of continuous lectures to deliver
information of the terrain movement. Nevertheless,
it has been observed that there are several factors
with influence on the system accuracy, which can
be ranged and /or corrected.

47. 47
Wi-GIM results
Daily noise range
One of the main factors of data fluctuation which have
been observed is temperature which show daily and
seasonal influence.
Daily, the sampling time-step of 8 hours translates into a
three lectures in a fairly different temperature conditions,
and hence a fairly different lectures in a temperature-
affected sensor, generating a daily range.
Seasonally, general temperature fluctuations affect
general trends of measures, and require long datasets
to be corrected.
Seasonal fluctuation

48. 48
Wi-GIM results
Daily fluctuation due temperature can be
corrected by relating both variables. A linear
relation between them can greatly improve
accuracy to a daily fluctuations under 5 cm.

49. In order to gather more information about the system response to a subsidence phenomena, the
displacement has been forced in two of the sensors.
49
Wi-GIM results

50. It has been seen that system responds adequately to the forced movement in the relation
between the displaced sensors and the rest of the network within the accuracy limits.
50
Wi-GIM results

51. Future of Wi-GIM
51
•Geotechnical Engineering
Centre at University of Alberta
•Research mandate to apply
and test innovative
monitoring systems
•Bilateral agreement of
cultural and scientific
cooperation between DST-
UNIFI and Department of
Civil and Environmental
Engineering of University of
Alberta
•Application to Fountain
Slide (Canada)

52. Future of Wi-GIM
52
•Oriente de Michoacán
•Deep Seated Gravitational
Slope Deformation
•4 million m3

53. Conclusions
5353
Precision (raw data): 8-10 cm
Precision (filtered): 2-3 cm
Battery duration: ≈ 1 month
Maximum range distance: 140 m
Cost : ≈ 100 €/node
Precision (filtered): <1 cm
Reduce node size
Increase battery duration
Cost (industrialized): ≈ 50-70
€/node
NOW FUTURE

54. 54
 Accuratezza misure UWB
 Distanza fra nodi
 Rapida installazione
 Basso costo
 Bassa vulnerabiità
 Elevata autonomia
In corso di approfondimento:
• Effetto multipath
• Influenza fattori atmosferici
• Influenza direzionalità antenne
• Influenza ostacoli (altezza antenne)
• Posizionamento 3D
Promettente per earthflow e grandi frane in roccia