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127-02-2013 OWF Horns Rev 3 and Kriegers Flak - Geo Investigations
HR3 & KF Geo Investigations
UXO Desk Study 2012
UXO - UneXploded Ordnance
Unexploded Ordnance (UXO) is defined as military munitions that have been:
• Primed, fused, armed or otherwise prepared for action
• Fired, dropped, launched, projected, or placed in such a manner to constitute a
hazard to operations, installations, personnel, or material
• Remain unexploded either by malfunction, design, or any other case
Generally and historically not an integrated or well-known part of Danish offshore pre-
investigations until recently (especially Anholt OWF).
Ad hoc surveys and actions taken care by FKP EOD, SOK (Danish Marine)
Energinet.dk hired Danish Consultants NIRAS led by former weapon/UXO officer Erik K.
Lauritzen to conduct UXO Desk Studys for the two OWFs
227-02-2013 OWF Horns Rev 3 and Kriegers Flak - Geo Investigations
UXO Desk Study 2012 – Results HR3:
327-02-2013 OWF Horns Rev 3 and Kriegers Flak - Geo Investigations
UXO danger zone in the middle of HR3 pre-investigation area.
Military training zone Oksbøl (5 km radii to 20km). The maximum safety zone
extends to 25 km (light pink). A previous 33 km zone is indicated by the green line.
UXO Desk Study 2012 – Results - HR3
427-02-2013 OWF Horns Rev 3 and Kriegers Flak - Geo Investigations
From: ”Munition im Meer”:
Red: British mines from WWI
Green: German LMB mines from WWII
Blue: British air deployed Mk I-IV from WWII
Aluminium! Danger zone!
SW of HR3, not relevant
Iron, rusted away, diffuse
UXO Desk Study 2012 – Results - HR3
527-02-2013 OWF Horns Rev 3 and Kriegers Flak - Geo Investigations
According to the reports, the last time a LMB mine was found i Danish waters was in Ålbæk
Bugt in 1992. The batteries were dead.
A complex trigger system, very unlikely to explode, however very complex!
UXO Desk Study 2012 – Results - HR3
627-02-2013 OWF Horns Rev 3 and Kriegers Flak - Geo Investigations
According to the reports, a few of the LMB mines exploded during last part of WWII
The 70 mines were dropped by ships along two paths, with given coordinates for the end
points. No mines have ever been detected by NATO (SSS), nor reported found!
UXO Desk Study 2012 – Results HR3
727-02-2013 OWF Horns Rev 3 and Kriegers Flak - Geo Investigations
Contamination of HR3 OWF development area. Green denotes contamination class B2,
yellow denotes contamination class B3 and red denotes contamination class B4.
UXO Desk Study 2012 – Results HR3
827-02-2013 OWF Horns Rev 3 and Kriegers Flak - Geo Investigations
UXO risk levels for working on the seafloor in the HR3 area:
Western part: Direct and indirect seabed interactions (A2 – A4) can be performed within the
tolerable risk level (ALARP).
Eastern part (military exercise area): Direct seabed interactions (A3 and A4) in the eastern
part require risk mitigation. Indirect seabed interactions (A2)
can be performed within the tolerable risk level (ALARP).
Central part (danger zone on Nautical Chart):
All seabed interactions (A2 – A4) require risk mitigation.
Mitigation measures, examples
UXO HR3 and geotechnical investigations 2013
• It has been decided that the geotechnical contractor (Provider) is responsible
for carrying out necessary UXO survey and –evaluations before borehole
drilling, CPT testing etc. – on all locations within OWF HR3. Necessary:
Platform legs, anchors etc.
27-02-2013 9OWF Horns Rev 3 and Kriegers Flak - Geo Investigations
UXO Desk Study 2012 – Results KF
1027-02-2013 OWF Horns Rev 3 and Kriegers Flak - Geo Investigations
UXO Desk Study 2012 – Results KF – no threats!
1127-02-2013 OWF Horns Rev 3 and Kriegers Flak - Geo Investigations
UXO KF and geotechnical investigations 2013
• It has been decided that there is no requirement to carry out UXO survey
within OWF KF prior to performing boreholes etc.
27-02-2013 12OWF Horns Rev 3 and Kriegers Flak - Geo Investigations
27 February 2013 13OWF HORNS REV 3 AND KRIEGERS FLAK
Offshore Wind Farms
Horns Rev 3 and Kriegers Flak
Geo Investigations 2012-2013
Preliminary Geotechnical investigations
Planned program
Main purposes of the geotechnical investigation
• Verify the geological units found, mapped and preliminary interpreted during
the geophysical survey in 2012 down to below the expected foundation depths
of wind turbines
• Characterise these geological units in geological and geotechnical terms, and
obtain geotechnical data and parameters for the observed soils and layers
• Correlate the geotechnical and geological results with interpreted geophysical
results for detailed delineation of sub-seabed sediment types and layers
• Verify geophysically found/indicated possible accumulations of shallow gas,
buried channels, soft sediments, etc.
• Be able to adjust the preliminary 3D geological model based upon the
geophysical survey results
27 February 2013 14OWF HORNS REV 3 AND KRIEGERS FLAK
Horns Rev 3 – Site specific focus points
In planning of the positions of the geotechnical investigation the following focus
points have been identified from the geophysical survey:
• Variations and organic layers in the Holocene sediments
• Possible presence of soft sediments in local channels in the Holecene Fresh
Water Unit
• Soft and/or organic sediments in the Horns Rev Valley
• Variations and organic layers in the Eemian sediments
• Variations with depth of the till in the Saalian glacial Unit, especially in the
westernmost part of the area, where the unit is high lying
27 February 2013 15OWF HORNS REV 3 AND KRIEGERS FLAK
Horns Rev 3– Geotechnical challenges
The following geotechnical challenges in relation to Wind Turbine installation
have been identified:
• The high lying till (in the westernmost part of the area) might have a high
content of stones and boulders
• Soft sediments in the Horns Rev Valley and locally in the Holocene sediments
27 February 2013 16OWF HORNS REV 3 AND KRIEGERS FLAK
Kriegers Flak – Site specific focus points
In planning of the positions of the geotechnical investigation the following focus
points have been identified from the geophysical survey:
• Variations in the Holocene sediments
• Possible presence of the Kriegers Flak Clay in the upper till
• Variations with depth of the upper and lower till
• Sediments in the channels in the limestone surface
• Variations with depth of the limestone, especially in areas with high lying
limestone and below channels
27 February 2013 17OWF HORNS REV 3 AND KRIEGERS FLAK
Kriegers Flak – Geotechnical challenges
The following geotechnical challenges in relation to wind turbine installation
have been identified:
• Stones and boulders might be present at seabed
• The till might have a high content of stones and boulders
• The lower till might be very hard and "rock-like"
• The limestone might contain layers of chert (flint)
27 February 2013 18OWF HORNS REV 3 AND KRIEGERS FLAK
Preliminary geotechnical investigations.Planned field program
The planned scope of field investigations at each of the sites Horns Rev 3 and
Kriegers Flak includes:
12 – 15 Boreholes
• depth of 50 m below seabed
• extraction of intact and disturbed samples
12 – 15 Continuous Cone Penetration Tests (CPT)
• placed adjacent to each borehole
• depth of 50 m below seabed
• If refusal of continuous CPT: Optional down the hole CPT in adjacent borehole
or blind drilling for continuous CPT depending on the soil conditions
27 February 2013 19OWF HORNS REV 3 AND KRIEGERS FLAK
Preliminary geotechnical investigations. Planned field program
The exact locations for the boreholes/CPT have not been defined yet, but will be
distributed within the areas to examine the various geological conditions.
Final locations will be decided when the final results of the geophysical survey
2012 is available.
27 February 2013 20OWF HORNS REV 3 AND KRIEGERS FLAK
27 February 2013 21OWF HORNS REV 3 AND KRIEGERS FLAK
Preliminary geotechnical investigations. Example of locations of boreholes/CPT.Horns Rev 3
Map: Base Eemian Marine
Borehole and CPT
Preliminary geotechnical investigations. Example of locations of boreholes/CPT.Kriegers Flak
27 February 2013 22OWF HORNS REV 3 AND KRIEGERS FLAK
Map: Lower Till / Top of Cretaceous Chalk
Borehole and CPT
Preliminary geotechnical investigations.Planned program - Laboratory tests
The planned scope of laboratory tests at each of the sites Horns Rev 3 and
Krigers Flak will include:
• Geological description and classification of soil and rock
- and the below listed classification tests as appropriate:
• Water content
• Bulk density
• Grain size distribution
• Atterberg limits
• Particle density
• Density index of granular soils (emin / emax)
• Loss of ignition
27 February 2013 23OWF HORNS REV 3 AND KRIEGERS FLAK
Preliminary geotechnical investigations.Planned program - Laboratory tests
The planned scope of laboratory tests at each of the sites Horns Rev 3 and
Krigers Flak will include the below listed chemical tests as appropriate:
• Chloride content
• Content of CaCO3
• Sulphate content
27 February 2013 24OWF HORNS REV 3 AND KRIEGERS FLAK
Preliminary geotechnical investigations.Planned program - Laboratory tests
The planned scope of laboratory tests at each of the sites Horns Rev 3 and
Krigers Flak will include the below listed special laboratory tests as
appropriate:
• Thermal resistivity (samples near seabed)
• Oedometer test
• Unconsolidated Undrained (UU) triaxial test
• Consolidated Undrained (CU) triaxial test
• Consolidated Drained (CD) triaxial test
• Unconfined Compression test
27 February 2013 25OWF HORNS REV 3 AND KRIEGERS FLAK
Preliminary Geotechnical investigations. Geotechnical Reporting and digital deliverables
Geotechnical reporting:
The results of the geotechnical investigation will be presented in a
Factual Geotechnical Report for each of the investigation areas.
Digital deliverables:
The data results of the geotechnical investigation will be delivered in AGS-
format.
27 February 2013 26OWF HORNS REV 3 AND KRIEGERS FLAK
Preliminary Geotechnical investigationReporting – Factual Geotechnical Report
27 February 2013 27OWF HORNS REV 3 AND KRIEGERS FLAK
The Factual Geotechnical Reports will include:
• Introduction and scope of Report
• Field operation
• Factual results
• Geotechnical boreholes
• CPT results – measured data and calculated values
• Laboratory tests
• Soil conditions
• Geological overview
• Description of found results
• Presentation of typical geotechnical characteristics
Preliminary Geotechnical investigations.Reporting – Factual Geotechnical Report
27 February 2013 28OWF HORNS REV 3 AND KRIEGERS FLAK
Enclosures to Factual Geotechnical Reports will include:
• General and detailed location plan with test locations
• Legends of definition
• Borehole profiles including geological description and laboratory tests results
• CPT profiles, including measured, calculated data and soil profile
• Laboratory test results
• Summary tables for boreholes, CPT´s and laboratory tests
• Photos of samples
Preliminary Geotechnical investigations.Reporting – Example CPT Results
27 February 2013 29OWF HORNS REV 3 AND KRIEGERS FLAK
Preliminary Geotechnical investigations.Reporting – Example Borehole profile
27 February 2013 30OWF HORNS REV 3 AND KRIEGERS FLAK
27 February 2013 31OWF HORNS REV 3 AND KRIEGERS FLAK
Offshore Wind Farms
Horns Rev 3 and Kriegers Flak
Geo Investigations 2012-2013
Preliminary Geotechnical investigations
Planned / Considered program
27 February 2013 32OWF HORNS REV 3 AND KRIEGERS FLAK
Geotechnical 2013 – Planned / Considered Program
Additional initiatives other than the geotechnical borehole / CPT programme:
1. Acoustic CorerTM, especially at Kriegers, Flak to locate and quantify possible
occurrences of boulders (and other shallow geohazards)
2. Adjustment of the 3D stratigraphical model from Geophysical 2012 with the
lithological, and interpreted, data from boreholes/CPTs
3. A synopsis of the different geo reports into a Preliminary Geoengineering report
27 February 2013 33OWF HORNS REV 3 AND KRIEGERS FLAK
Acoustic CorerTM
Acoustic CorerTM pre-investigations with the following objectives:
• Complete information for the identification of significant acoustic anomalies,
consistent with geohazards ≥0.5m diameter such as buried objects and boulders.
• Complete information for the identification of shallow gas located within the Core.
• Comprehensive description of the sediment stratigraphic column in step with the
acoustic impedance contrasts that exist in the transition between the layers.
• Correlations between borehole/CPT data and between the acoustic core data
• A statistical analysis of significant acoustic anomalies with respect to anomaly
size, anomaly depth of burial, and with which geological unit the anomalies are
associated e.g. number of boulders per unit volume, size distribution of boulders.
• The objectives being to provide the potential Bidder with information by
which they can determine areas within the wind farm that pose the most
risk to piling operations. Buried objects and boulders present a considerable
potential cost and schedule risk during the installation of offshore infrastructure.
• Proposed amount of Acoustic CoresTM: c. 15 at Kriegers Flak and c. 5 at Horns Rev 3
• Relatively expensive – less than, but in the order of a borehole
27 February 2013 34OWF HORNS REV 3 AND KRIEGERS FLAK
Acoustic CorerTM
• The Acoustic Corer™ 3D technology uses multi-aspect acoustic intensity imaging
to delineate sub seabed stratigraphy and buried geohazards such as boulders,
hard layers, shallow gas, and abandoned seabed infrastructure.
• The Acoustic Corer™ unit consists of two sonar heads attached to each arm of the
12m boom. This boom rotates 180° thereby creating a 360° acoustic core.
• Every measurement lasts c. 24 hours, once the equipment is positioned on the
seabed, and has a penetration of up to 30m (most effective in the upper 12m)
27 February 2013 35OWF HORNS REV 3 AND KRIEGERS FLAK
A substantially larger ”diameter” than a borehole
27 February 2013 36OWF HORNS REV 3 AND KRIEGERS FLAK
Acoustic CorerTM
27 February 2013 37OWF HORNS REV 3 AND KRIEGERS FLAK
Update the 3D geological model with borehole/CPT data
• Based on the seismic results from the Geophysical survey in 2012 a 3D stratigraphic
Geological Model is constructed in Kingdom Suite.
• It is considered to update and adjust this digital model with the geological/lithological,
and interpreted, results from the planned boreholes and CPTs (and possibly Acoustic
Corers) into a preliminary Geotechnical Model that will be part of the Delivery.
• It is the intention, that this preliminary Geotechnical Model after the pre-investigations
will form the basis for further developments and refinements into a more detailed
Geotechnical Model and eventually into an Engineering Model based on additional
geophysical and geotechnical site investigations.
27 February 2013 38OWF HORNS REV 3 AND KRIEGERS FLAK
Preliminary Geoengineering Report
Note that the outcome of Geophysical 2012 and Geotechnical 2013, including possible
Acoustic CorersTM 2013, will be:
• Raw, Processed and Interpreted Data
• Reports, Profiles, Digital Models, Charts and Maps
• Everything primarily of a ”Factual” character
We suggest a Preliminary Geoengineering Report to be prepared as part of the
Final Delivery, including an updated 3D Geotechnical Model (see previous slide): The
character of this Preliminary Geoengineering Report is planned to be:
• A synopsis of the results from the geo pre-investigations, including UXO
• An integrated/interpretative/conclusive geoengineering report
• A technical ”executive” report
The time frame for the Preliminary Geoengineering Report will have the same final
deadline as the EIA does: end of March 2014.
.
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