Presentation in the Norwegian Geotechnical

Society meeting,

Oslo 15-16.10.2013,

Pauli Saksa, Geosto Oy

Suomen Geoteknillinen Yhdistys –Finnish Geotechnical Society

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Major applications of applied geophysics arein exploration and nuclear waste disposal sectors.

Fairly limited use of geophysics in environmental and geotechnical sectors.

Spin-off techniques and instruments from nuclear waste disposal research – like excavation damage zone (EDZ) analysis.

Summaries of identified projects are given on the following slides. Organisations are kindly acknowledged to provide the materials.

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Project by Geological Survey of Finland

Contacts: Taija Huotari-Halkosaari and Marit Wennerström

Objective is to develop detection of bedrock weakness zones and interpretation in 3-D. Measurements are adapted to urban environment constraints. Project compiles a guideline of suitable investigation methods for rock engineering targets and observed best practises to integrate geological and geophysical results into a site model.

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Methods: GPR, electrical imaging, electromagnetic (horizontal loop), gravity, magnetic, borehole logging suite, electrical mise-a-la-masse method (borehole to surface).

Example:

0-2

5m

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Projects by Geosto Oy

Contact: Pauli Saksa

Methods: multi-frequency short coil spacing systems (horizontal and vertical co-planar loops). Also time domain like GPR, natural field and transient- EM.

Objectives: study applicability in various geotechnical and hydrogeological uses, develop interpretation and gain experience of methodology. Example instrument below, GSSI EMP-400 profiler.

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Successful geotechnical targets: pipes, material fills, underground metallic and concrete structures, soil layer variations, rock quality variations.

Depth range 0 – 10 m, penetration also in clays more than 5 meters.

Control soil drillings

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NEEDS◦ Accurate monitoring of contamination leakages from rock and

liquid waste areas, monitoring of earth structures (dams, fills)◦ Environmental management and control, baseline characterisation◦ Monitoring of surface waters (lakes, pools)

APPROACH◦ Application of new high-resolution geophysical instrumentation◦ Research of influencing terrestrial-meteorological parameters◦ Improvement of data analysis methods

BENEFITS◦ More reliable and accurate contamination detection◦ Better positioning of (ground)water sampling and actions◦ Use of non-invasive ecological technologies

USERS◦ Mining companies◦ Waste treatment centers, industry with waste disposal◦ Consulting and planning companies, regulators and authorities

FUNDING: The Finnish Funding Agency for Technology and Innovation

www.geosto.fi, Contact: Pauli Saksa

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Project by Destia Oy, Master planning stage of Klaukkala by-pass road.

Contact: Minna Löytynoja, Ref: TIEH 2100057-08 report.

Achievements: Site with artesian groundwater conditions limited drillings. Electrical imaging contrained with resistivity logging provided detailed picture of thick clay thickness and water content variation.

0m

10m

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Projects by Roadscanners Oy

Contact: Timo Saarenketo and Pekka Maijala

Methods: Highly integrated imaging and scanning products for road and railway structural and foundation investigations.

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905 nm8-12 microm0.1 – 1 m

GPR Thermal CameraLaser Scanner

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Achievement: Fully integrated and efficient instrumentation, analysis and software technologies for world-wide infrastructure clientele.

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INTEGRATED ANALYSIS OF 2D LASER SCANNER, GPR AND FWD DATA

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Optical and acoustic borehole logs give oriented information of fractures and other geological features.

Data coverage from intensively fractured zones (no core orientation).

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Projects by Drillcon / Suomen Malmi Oy

Contact: Karla Tiensuu and Ville Sipola

Project: Posiva Oy, high-level nuclear waste disposal. Method: Analysis of developed EDZ in drill & blast tunnels is

based on radar wave field dispersion characteristics. Deeper EDZ with more microfractures attenuates the high frequency component from the calculated spectrum.

Reference: Heikkinen et al., Posiva Oy working Report 2010-04.

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Clear focus has been on the development of electromagnetic and electrical methods.

Traditional use of refraction seismics mainly. Progress in tomography processing and mechanical sources.

Few surveys with surface wave and reflection seismics.

Trend to combine several methods per survey, better overall result with minor cost increase.

Geotechnics gain advantage and spin-offs from nuclear waste and mining industry activities.

THANKS FOR YOUR ATTENTION.

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