11 Years Engineering Geology Fieldwork in

Falset, Salou, and CambrilsScience From Fieldwork

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What did we Produce ?

Why did we ?

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Why did we do science during fieldwork?

• Keep the staff happy• Intellectual interest• Keep students happy

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Why keep students happy?

• It is not every year the same• The data gathered and products produced

are used, and not only for a ‘mark’

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Are the students happy?

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What did we Produce? (1)

• Qualitative Weathering rating• Equotip as rock mechanics strength tester• Visual roughness characterization• Intermediate scale laser roughness tester• Quantitative weathering rating• Problem index rating for mapping (PRI)• Slope stability probability classification

(SSPC)• 3D models on data of Falset

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What did we Produce? (2)

• Methylene Blue tests• Excavation rating model• ‘Hamertje tik’• Cementation effects due to Gypsum• Numerous other features which did not (yet)

made it into an article

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Equotip as rock mechanics strength tester

0

50

100

150

200

0 200 400 600 800 1000

UCS

(MPa

)

Equotip (L)

UCS vs. Equotip(after Verwaal et al., 1993).

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Visual roughness characterizationCONDITION OF DISCONTINUITIES factor

Roughnesslarge scale (Rl)

(visual area > 0.2 x 0.2 and < 1 x 1 m2)

wavyslightly wavycurvedslightly curvedstraight

1.000.950.850.800.75

Roughnesssmall scale (Rs)

(tactile and visual on an area of20 x 20 cm2)

rough stepped/irregularsmooth steppedpolished steppedrough undulatingsmooth undulatingpolished undulatingrough planarsmooth planarpolished planar

0.950.900.850.800.750.700.650.600.55

Infillmaterial (Im)

cemented/cemented infillno infill - surface staining

1.071.00

non softening & sheared material, e.g. free of clay, talc, etc.

coarsemediumfine

0.950.900.85

soft sheared material, e.g. clay, talc, etc.coarsemediumfine

0.750.650.55

gouge < irregularitiesgouge > irregularitiesflowing material

0.420.170.05

Karst (Ka) nonekarst

1.000.92

Discontinuity characterization (after Hack et al., 1995, 1998).

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Intermediate scale laser roughness tester

mm

Laser roughness profile of sample in photo (after Baardman, 1993)

≈ 8 cm

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Slope stability probability classification (SSPC) (1)

AP (deg)

TC (c

ondi

tion

of d

isco

ntin

uity

) (-) 1.00

0.80

0.60

0.40

0.20

0.00 0 10 20 30 40 50 60 70 80 90

5 %30 %discontinuity stable

with respect to sliding

discontinuity unstable with respect to sliding

70 %50 %

95 %

(joint 3 example)

- 90 - AP + slope dip (deg)

TC (c

ondi

tion

of d

isco

ntin

uity

) (-)

0 10 20 30 40 50 60 70 80 90

1.00

0.80

0.60

0.40

0.20

0.00

70 %

5 %

95 %

discontinuity stable with respect to toppling

discontinuity unstable with respect to toppling

50 %30 %

(1)

(2)

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Slope stability probability classification (SSPC) (2)

1

0.1

10

0.0 0.2 0.4 0.6 0.8 1.0

5 % 10 % 30 % 50 %

95 % 90 %

70 % probability to be stable > 95 %

probability to be stable < 5 %

(example)

ϕ’mass / slope dip

Hm

ax /

Hsl

ope

Dashed probability lines i ndicate that the number of slopes used for the devel opment of the SSPC sys tem for these sec tions of the graph is li mited and the probabili ty li nes may not be as certain as the probability lines drawn with a conti nuous li ne.

(3)

(1) +(2) +(3) give

Likelihood of a slope to be stable

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Soil testing (Falset, Spain)

(Photo courtesy Zigterman)

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‘Hamertje tik’

UCS (MPa)

estim

ated

inta

ct ro

ck st

reng

th (M

Pa)

0 50 100 150

0

50

100

150

200Tertiary congl./sst.

Jura limest.

Tg23

Tg22

Tg21

Tg1 sst.

Tg1 congl.

H slate

H congl.

H sst.

H gneiss

granodiorite

(estimated = UCS)

c. averages per unit

estimated = 1.19 +0.910 * UCSR2 = 0.78

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Geotechnical properties and slope stability problems in weak rocks or cemented soils (Upper Musschelkalk-

Keuper transition, Falset, Spain, 2001)

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Karst and cemented (crust) layers. (Falset, Spain,

2001)

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Future

• Continue at location• Weathering – time relation• In-homogeneity

• Shallow 3D resistivity to identify crusts ?• ??

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Tunnel excursions(Tunnels de Garafe, Barcelona, Spain)