Assessing the Ground Response to Urbanization in the Fiumicino area by Combining Geological and Geotechnical Data with Satellite InSAR Data

Size: px

Start display at page:

Download "Assessing the Ground Response to Urbanization in the Fiumicino area by Combining Geological and Geotechnical Data with Satellite InSAR Data"

Amber Brooks
5 years ago
Views:

1 Assessing the Ground Response to Urbanization in the Fiumicino area by Combining Geological and Geotechnical Data with Satellite InSAR Data P. Mazzanti F. Bozzano, C. Esposito, M. Patti, A. Rocca La Missione COSMO-SkyMed: Stato dell Arte, Applicazioni e Prospettive Future Roma, Agenzia Spaziale Italiana,

2 Project objective Assessing the role of loading in order to define a predictive model of subsidence in delta plains characterized by the presence of compressible layers

3 Study Area: Tiber river delta plain Study area Leonardo Da Vinci Fiumicino Airport

4 Geological Conditions Evolution of the Tiber river delta plain from 15,000 years BP to the present... From Milli et al, 2013

Geological Conditions Evolution of the Tiber river delta plain from 15,000 years BP to the present led to a) Recent alluvial; b) recent dune and inetrdune sediments; c) ancient alluvial sediments; d)

5 Geological Conditions Evolution of the Tiber river delta plain from 15,000 years BP to the present led to a) Recent alluvial; b) recent dune and inetrdune sediments; c) ancient alluvial sediments; d) ancient dunes; e) pleistocene pyroclastites; f) travertins; g) clay, sandy clay, sands; lens of gravels with malacofauna; h) gravel and sandy gravel; i) inner delta limit; l) ancient rclaimed ponds; m) old channels. (Bellotti et al., 1989). Very complex geological conditions...

6 Geological Conditions Evolution of the Tiber river delta plain from 15,000 years BP to the present led to From Milli et al, 2013 Very complex geological conditions with strong lateral variations!

7 Detailed Geological Model Based on more than 480 stratigraphic borehole logs... Legend Localization of boreholes

.collected from: Bibliography Municipalities Fiumicino Airport

8 Detailed Geological Model Based on more than 480 stratigraphic borehole logs..collected from: Bibliography Municipalities Fiumicino Airport technical office National Roads Department Local companies Freelancers Analyzed together in order to achieve a homogeneous interpretation!

9 From the Geological Model to the Lithological Model to the Geotechnical Model Identification of the sedimentary terms involved in the subsidence process (compressible soils) Lithostratigraphic units (Milli et al., 2013) "sand, sandy silt and clay alluvial deposits" (HST) Mainly cohesive sediments Mainly non-cohesive sediments "peat and peat clay alluvial and lagoon deposits" (TST/HST) "clay and silty clay shelfal deposits" (TST/HST) "silty clay and clay lagoon deposits" (TST) "sand dune deposits" (HST) "sand and silty sand beachridge deposits" (HST) "sand and silty sand coastal barrier deposits" (TST)

10 From the Geological Model to the Lithological Model to the Geotechnical Model Identification of the sedimentary terms involved in the subsidence process (compressible soils) Mainly cohesive sediments Mainly non-cohesive sediments Lithostratigraphic units (Milli et al., 2013) "sand, sandy silt and clay alluvial deposits" (HST) "peat and peat clay alluvial and lagoon deposits" (TST/HST) "clay and silty clay shelfal deposits" (TST/HST) "silty clay and clay lagoon deposits" (TST) "sand dune deposits" (HST) "sand and silty sand beachridge deposits" (HST) "sand and silty sand coastal barrier deposits" (TST) Lithological unit lf 7 - "alluvial clayey silt" lf 6 - clayey peat" lf 2 - "silty clay and clay lagoon deposits" lf 8 - beachridge silty sands Different sedimentary terms with similar geotechnical behaviour have been grouped.

11 A-DInSAR analyses ERS ( ) Envisat ( ) COSMO-SkyMed ( )

12 Geological map vs A-DInSAR results Ponds (still not reclaimed in 1884) Large scale correlation in space If we look at a large scale, there is a good spatial correlation between InSAR results and geological conditions Historical geological map (from Amenduni, 1884)

13 Geological map vs A-DInSAR results Ponds (still not reclaimed in 1884) Large scale correlation in space If we look at a large scale, there is a good spatial correlation between InSAR results and geological conditions Legend Envisat (vel) mm/yr Historical geological map (from Amenduni, 1884)

14 Geological map vs A-DInSAR results (Cosmo-SkyMed)

15 A-DInSAR analyses

16 A-DInSAR analyses

17 Combination of geological/geotechnical model with A-DInSAR results Geological model A-DInSAR Legend Envisat (vel) mm/yr Legend Localization of boreholes + Bad correlation! why?

18 Training sites 10 areas characterised by a detailed geological model. One inner and one outer the delta plain

Combination of geological/geotechnical model with A-DInSAR results in the training area In

compressible deposits and the velocity of the measuring points.

settlement process is strongly time-dependent (especially for such soils); Strong geological

19 Combination of geological/geotechnical model with A-DInSAR results in the training area In the 10 areas under investigation it seems clear the relationship between the thickness of the compressible deposits and the velocity of the measuring points. CAUSES: Typology of foundations (shallow, deep); Age of buildings: the evolution of the settlement process is strongly time-dependent (especially for such soils); Strong geological lateral variability, i.e. we cannot neglect the depth of strata responsible of the settlement process (Boussinesq theory). mm years

Age of buildings Increasing urbanization in the area, in the last decades.

Refinement of main areas by using multitemporal data: Typology of data Year Colour

000 Map 2002 Colour Orthophotos 1998 B/W Orthophotos 1996 B/W Orthophotos 1988 1:10.

20 Age of buildings Increasing urbanization in the area, in the last decades. The area has been investigated by supervised classification of satellite optical data. Refinement of main areas by using multitemporal data: Typology of data Year Colour Orthophotos 2011 Colour Orthophotos :5.000 Map 2002 Colour Orthophotos 1998 B/W Orthophotos 1996 B/W Orthophotos : Map : Map Legend Age of building before

Effective Thickness of compressible soils The information of depth

also taking into account the thickness For every layer, starting

of Thickness (Sp*) has been calculated, taking into account the

21 Effective Thickness of compressible soils The information of depth of compressible layers has been included in the conceptual model, also taking into account the thickness For every layer, starting from information achieved by stratigraphic log, an effective value of Thickness (Sp*) has been calculated, taking into account the depth and the presence of backfill layers above (considered indeed as load ).

22 Now seems to work! Area 9 (Airstrip) northern sector. Envisat data Same age (last substantial works); Different geological conditions;

23 Same age (last substantial works); Different geological conditions; Now seems to work! Cosmo-Skymed Modified from Manassero & Dominijanni, 2010 Torba

24 Now seems to work! The high resolution data highlights the lithological transition between Inner Delta Plain (compressible and soft soils) and Ponte Galeria Hills (sandy and OC soils) Same age (last substantial works); Different geological conditions;

25 Now seems to work! Area 10 Central area Different age. Similar geological conditions. Vel (mm/yr) x Envisat data

26 Now seems to work! Area 10 Central area Similar age Similar geological conditions; Different foundations! Vel (mm/yr) x Envisat data

27 Now seems to work! Deep foundations Shallow foundations Similar age Similar geological conditions; Different foundations!

28 Testing the predictive model on COSMO-SkyMed data Some examples: 0-5 years Age 0-5 years Expected settlement = 7 cm Measured settlement 6 cm Cum. displ. (mm) years Age years Expected settlement = 3 cm Measured settlement = 3 cm Cum. Displ. (mm)

29 Looking for a generalized prediction model! By combining the subsurface geology (in terms of effective thickness (Sp*) of lithological units and related geotechnical features), the load emplacement times (t) and the surface settlement rates (V), a model able to predict the evolution of the subsidence was developed. Specific coefficients were achieved for each lithological unit (β), thus allowing to predict the subsidence rate over time caused by a new load to the surface.

30 Predicted subsidence 5 years 10 years 15 years 20 years

31 Predicted subsidence 30 years 40 years 50 years 60 years

32 CONCLUSIONS Unfortunately for A-DInSAR technology geology and geotechnics is a very complex matter very often out of schemes.fortunately for geologists and geotechnical engineers A-DInSAR exists and through the use of high resolution data like Cosmo Sky- Med geological processes can be better understood and predicted!

Integrated geological approach to the study of coastal subsidence in Emilia-Romagna. Luisa PERINI Calabrese Lorenzo, Luciani Paolo, Severi Paolo,

Integrated geological approach to the study of coastal subsidence in Emilia-Romagna Luisa PERINI Calabrese Lorenzo, Luciani Paolo, Severi Paolo, Subsidence hazard of Emilia-Romagna coastal plain Caputo