Effect of geological characteristics on differential weathering of low-graded metasedimentary rock slopes

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*Corresponding author: Yong-Seok Seo E-mail: [email protected]

Received May 6, 2013; Revised May 15, 2013;

Accepted May 21, 2013

ᱡᄡᖒ♕ᱢᦵᔍ໕ᨱᕽḡḩ✚ᖒᯕ₉ᄥ⣮⪵ᨱၙ⊹۵ᩢ⨆

୨ැֽ ȵছ૳জ ȵହࡣ෭

Ҽধڙ ॢĶսۙڙėԐ,XBUFSٍĵڙ ٍĵڙ

܁ধڙ ߿Қʂॡİݓĵঞąęॡę İս

Ҽধڙ ʂۻʂॡİݓъѓۦėॡę İս

Effect of geological characteristics on differential weathering of low-graded metasedimentary rock slopes

Hae-Geun Jeong

¹

, Yong-Seok Seo

²

*, Myung-Hyeok Ihm

³

1

K-water Institute, Korea Water Resources Corporation, Researcher

2

Department of Earth and Environmental Sciences, Chungbuk National University, Professor

3

Department of Geotechnical Engineering for Disaster Prevention, Daejeon University, Professor

ABSTRACT: This study evaluates correlation between petrographic characteristics and weathering grade of low-graded metasedimentary rocks mainly consisting of phyllite. Weathering grade of rock material was determined based on the results of geological survey. The Schmidt hammer test was carried out to obtain estimates of strength of rock materials. Point counting and microscopic observation were also conducted to analyze mineral composition and to measure spacing of foliation for 9 rock specimens. As a result of microscopic analysis, as the weathering grade was lower, the quartz was found more in quantity, consequently making rock stronger against weathering process. On the other side, lower weathering grade of rock resulted in less content of mica which is weak against weathering process. In addition, the rock materials with closer foliation spacing are found to be weaker in strength and have higher weathering grade.

Keywords: Low-graded metasedimentary rocks, Weathering grade, Mineral composition, Spacing of foliation, Schmidt hammer test

ߣ΀ ҆ȦЛقԴəߎϔؒںܼ֮ڷͿ۹ѺՁࣅۺؒΪق՚ॠəؒԵںʂԜڷͿؒԵॡۺ࣢ݜęॄজʪۆԜěՁقʂॠي

қԵॠٕɰইۤݓݗܓԐεࣀॠيؒԵۆॄজʪεĀ܁ॠٕČ ĵՁؒԵۆÌʪÉں߸܁ॠşڦॠي֙й࣡३Ϣࢬ֟࣡ε

֬֨ॠٕɰÒ֨Βۆইйąчठě޶ںࣀॠيܳĵՁġНۆҙक़ҼٮْνۆÂüںࠑ܁ॠٕɰؒԵ֨ΒۆইйąқԵ

ĀęقۆॠϸॄজʪÀǰںս΀ॄজقÌॢԵٖՁқۋψČ ॄজʪÀȭںս΀ॄজقأॢڏϿՁқۋψڹìڷͿǣࢍǮɰ

̚ॢْνÂüۋܙںս΀ÌʪəǰČॄজʪəȭڹìڷͿǣࢍǮɰ

ܳڅر۹ѺՁࣅۺؒ ॄজʪ ġНܓՁ ْνÂü ֙й࣡३Ϣࢬ֟࣡

$PQZSJHIU ,PSFBO5VOOFMMJOHBOE6OEFSHSPVOE4QBDF"TTPDJBUJPO

ᕽು

ڍνǣ͆ۆҚʴҙقԴǫʴҙεÀͿݓβϸԴқ पॠə٢ߎʂݓًقəݓݗॡۺڷͿ۹ѺՁࣅۺؒ

Ϊق՚ॠə۾ࣺؒ, ߎϔؒ, ठؒˣęԵধؒ̚ə

ԵধőԓّؒˣɰتॢؒԵۋқपॢɰ. ۋ˞ݓࠗ

ڹęäս޲ͻقèࠚѺՁۚڌڷͿ֥čфɳࠗ

ˣۋьɵॠČەرėॡۺڷͿϔڍҝ؋܁ॢݓъ ق՚ॢɰ.

۹ѺՁࣅۺؒΪəϿؒęѺՁфѺ঍ۚڌۆ޲ۋ قۆॠيْν, ѹÒϸ, ֥čфɳࠗˣۆьɵ܁ʪÀ

޲ۋε҃ۋ϶, ۋ͠ॢ޲ۋəݓъǴقԴ޲ѻॄজ ۆڙۍۋʼ϶, ؒԵۆÌʪфǴĵՁ۹ॠ, ॄজࢹࠗ

ۆьɵˣڷͿۋر܋Ԑϸۋǣࢢȇ֨ė֨ңĨۆ

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Fig. 1. Regional geologic map of the study area (from Lee et al., 1997)

ڙۍۋʽɰ.

Santi (2006) əইۤقԴ۹ѺՁࣅۺؒˣٍأؒ

ۆ࣢ՁںşۦॠيқΪॣսەəşܵęۺۼॢ

֨ॹѓѪں܃֨ॠٕڷ϶, йĶǴقԴٍأؒۋқ पॠəݓʪ, ؒԵܛΪфėॡۺ࣢Ձں܁νॠي

ьशॠٕɰ. Lee et al. (2007)ڹߎϔؒقьɵॠə

ɳࠗНݗںؒԵ·ġНॡۺڷͿқΪॠČ, ۋ˞ۆً

ॡۺ࣢ՁںٍĵॠيԐϸфࢢȇˣۆًॡۺ३Ե قۋڌॣսەʪ΀܁͟ۺۍًॡ܁սε܃֨ॢ

цەɰ. ڍνǣ͆قԴ۹ѺՁࣅۺؒΪقʂॢėॡ ۺٍĵəʪͿæԺęěʹॠيąҙČ՚ʪͿ, ߔڙ- ԜܳÂČ՚ʪͿ, ٢ߎʂεࣀęॠəĶʪˣقԴԐ ϸфࢢȇۆ؋܁ՁқԵқآۆٍĵÀɰսۋΘر ݓČەɰ(Shin et al., 2003; Koo et al., 2008; Um, 2008; Cho et al., 2010). ٽĶقԴʪߎϔؒқपݓً

ۆ ԐϸңĨق ʂॢ ԐͻÀ ɰս ҃ČʼČ ەɰ (Tinoco and Salcedo, 1981; Park et al, 2011; Tanyas and Resat, 2013). Koçkar and Akgün (2003) ڹ۹ѺՁ ࣅۺؒқपݓًقԴْνьɵęॄজͿۍ३ٍأজ

ʽݓъقæԺʼəࢢȇۆÚĵҙ҃Ìęěʹʽ

Ԑͻεьशॢцەɰ.

۹ѺՁࣅۺؒۆॄজεݓѕॠəܳڅۍڷͿəѺ Ձۚڌʴ؋ԦՁʼəॄজقࠄأॢĵՁġНęٍأ ϸں঍ՁॠəْνÀەɰ. ҆ȦЛڹߎϔؒۋ۞

ьɵॠə۹ѺՁࣅۺؒݓًۆԐϸقԴইۤܓԐٮ

ইйąě޶ںࣀॠيġНܓՁфْνÂüۋ޲ѻ

ॄজقй࠘əٖॳںқԵॠəʚŔЀۺۋەɰ.

ইۤقԴISRM (1978)قԴ܃֨ॢॄজʪεۋڌॠ يؒъۆॄজ܁ʪεܓԐॠČ֙й࣡३Ϣεۋڌॠ يÌʪεࠑ܁ॠ϶, ԴͿɰδؒܛںԸ࢘ॠيߪ

9 ÒۆؒԵ֨Βε޽ࠄॠي֬ǴقԴчठں܃ۚॢ

঳, ठġইйąě޶ں֬֨ॠيġНܓՁфْν

ьɵԜࢗε܁͟ۺڷͿқԵ॥ڷͿ׆۹ѺՁࣅۺؒ

ΪۆؒԵॡۺ࣢ݜęॄজʪٮۆԜěՁںêࢹॠČ

ۙॢɰ.

ḡḩ

ٍ҆ĵݓًقəߎϔؒ, ڏϿठؒ, Եٖठؒ, Ā܁

ݗіڏؒ, őؒˣۋқपॠČەڷ϶, ۋ˞ڹߔܳʪ फ(Kwon and Jin, 1974)قԴə֨ʂйԜۆ৕ڏϿ

ठؒڷͿ, ڮՁʪफ(Park et al., 1977)قԴəČԦʂ

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Fig. 2. Panoramic view and the results of face mapping of the study area. The numbers indicate sampling locations for microscopic observation

Table 1. Rock name, weathering grade and average rebound number of Schmidt hammer determined in the field survey Observation

no.

Rock name

Weathering Grade (ISRM, 1978)

Ave. rebound number of Schmidt hammer

1 Phyllite HW 10>

2 Phyllite HW 10>

3 M-schist MW-HW 28

4 Phyllite HW 10>

5 Q-schist MW 40

6 Phyllite HW 10>

7 Dacite MW-HW 31

8 Quartzite SW 56

9 Dolomite MW-HW 26

࠮ҵͿ-١βʪҼ֟şۆॳԓνࠗķق՚ॠə৕ڏϿ

іڏϿȥνԵठؒڷͿܓԐʼČەɰ(Fig. 1). ۋݓ

ࠗ˞ڹ ʂߕͿ Қʴ(60°65°)ܳॳę ǫʴ(40°

45°) ąԐεÀݓ϶ݓًۺڷͿ֥čĵܓε҃ۍɰ.

߿ܳݓًںܼ֮ڷͿқपॠəॳԓνࠗęʂॳԓ őؒࠗڹٍ҆ĵݓًūݓҚʴ-ǫԴѓॳۆ̿ε঍

ՁॠϸԴқपॠČەɰ. ̚ॢॳԓνࠗęʴ֨ʂͿ

ʂҼʼəʂॳԓőؒࠗڹڮіԟں̿϶ʂҙқۦĀ

܁ʽԵٖڷͿĵՁʼرەČ, ॳԓνʮͿυۋ࣡ࠗę

ۍۿॠ϶, ֥čĵܓÀьɵॠşʪॢɰ(Kim and Cho, 1993). ۋ͠ॢݓݗॡۺ࣢ݜڹٍ҆ĵʂԜݓًę

ϔڍڮԐॠɰ.

ٍ҆ĵʂԜݓًۆܳѺҙقəܼԦʂԜҙ݇͆

ş(153 Ma163 Ma)قԦՁʽߔܳজÌؒߕÀěۓ ॠČەɰ. ۋ˞ڹъԜজÌؒ, ৕ڏϿজÌؒ, іڏϿ জÌؒ˞ۆ҄०জՁؒߕق՚ॠČ, ܼςǴݓՃς ݗۆъԜܓݔں҃ۋ϶, ܳՁқġНڹԵٖ, ܁ۤԵ,

৕ڏϿ, ÁԽԵˣۋɰ(Lee and Kim, 1997).

⩥ᰆ᳑ᔍ

ٍĵݓًڹʪͿæԺͿۍॠيĹ޳ʽԐϸۋ϶, ߪٍۤڹ330 m, Ԑϸȭۋə߯ʂ50 m, ԐϸąԐə

أ40°50°ͿԴݓݗॡۺڷͿʴێॢѺՁфѺ঍

ۚڌۋەؽʏًٖڷͿࣺɳʼəݓًۋɰ. ʂԜݓ

ًܛΪٮؒԜ, ॄজ܁ʪфҝٍ՚ϸۆԜࢗˣę

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Ïڹėॡۺ࣢Ձںࣷ؊ॠşڦॠيԐϸںʂԜڷ Ϳ܁нݓशݓݗܓԐфface mappingں֬֨ॠٕڷ

϶, ŔĀęəFig. 2ٮÏɰ. ʂԜĵÂۆݓݗڹߎϔ

ؒęठؒ, őؒ, ʮͿυۋ࣡, Եٖ؋ԓؒˣѺՁؒۋ

ܳεۋΘ϶, ْνÀ۞ьɵॠČ, ɳࠗ, ֥čˣই۹

ॢҝٍ՚ϸ˞ۋɰսқपॠČەɰ. ইۤقԴؒъ ۆॄজʪəISRM (1978)قԴ܃֨ॢşܵںܵڌॠ يĀ܁ʼؽڷ϶, ؒъÌʪə֙й࣡३Ϣεۋڌॠي

ࠑ܁ʼؽɰ. ॄজ܁ʪəۻъۺڷͿأÂॄজقԴÌ

ॄজūݓؒԵܛΪق˰͆ɰتॢॄজ܁ʪε҃ۋ Čەɰ.

ၶ⠙šₑ

Santi (2006) əйĶǴقқपॠəٍأؒںқΪ ॠϸԴѺՁۚڌقۆ३֖óॄজʼəġНęठν, ѹÒˣۆϸĵܓÀьɵॠəѺՁؒںप॥֨ࢅČ

ەɰ. ʂҙқۆْν˞ڹ܃ॢʽߕۺںÀݓəْࠗ

ۋǣͬ݋Ԝۆdomain ĵܓεÀݓČەڷ϶ێ܁ॢ

ÂüںÀݓϸԴ۞ބÒرݓəϸĵܓۍѹÒÀь ɵॠČەş˺ЛقࢢȇфԐϸңĨۆܳڅॢڙۍ ۋʼČەɰ.

҆Ԑϸقқपॠəߎϔؒںܼ֮ڷͿॢ۹ѺՁ ࣅۺؒΪəْνÀ۞ьɵॠČەڷ϶, ْνٮ؉थ ॱॠóԴͿɰδॄজ܁ʪۆًٖۋʂԜڷͿқप ॠČەɰ. ۋ˞ۆĵՁġНфْνьɵ܁ʪÀॄজ ʪقй࠘əٖॳںԕट҃şڦॠيইۤقԴߪ

9 ܛۆؒԵ֨Βε޽ࠄॠيчठں܃ۚॠČठġই йąě޶ں֬֨ॠٕɰ.

ၶ⠙᜽ഭၰšₑႊჶ

ؒԵ֨ΒۆġНܓՁҼٮْνьɵ܁ʪεқԵॠ şڦॠيؒԵчठں܃ۚॠيইйąě޶ں֬֨

ॠٕɰ. ইйąڹNikon Labophot-2 Pol Ͽʝںۋڌ ॠٕڷ϶, ʂНͬ݋ѕڱڹ10ѕڱںۋڌॠٕɰ. ч

ठڹْνقथॱॢѓॳęսݔʽѓॳڷͿ܃ۚॠ

ٕڷ϶, чठۆ5ÒًٖںԸ܁ॠيˣÂüपۍ࣡ࠢ

ڏࣶں֬֨ॠيġНߕۺҼεĵॠٕɰ. ̚ॢْν ьɵ܁ʪəْνϸقսݔॢѓॳقԴѹÒεঝۍ ॠϸԴࠑ܁ʼؽɰ.

ၶ⠙šₑđŝ

1 ѥ֨Β(Fig. 3(a))əۙ঍ۆৡԟ, ধԟ̚ə৕ԟ ۆÂԾԟں҃ۋəԵٖۓۙ؎ÚۋÀܳεۋΘ϶, ԵٖۓۙÂۆąćÀϼঝॠݓ؍Čҋ०Ըĵܓ(suture structure) Àьþʼݓ؍əɰ. ؒԵ֨ΒقԴъݡä νə৕ڏϿ˞ۋܳεۋΘ϶, ۻߕۺۍԟůʪؒȥ ԟۋǣȥ৕ԟćَͿر˃ڏìڷͿ҃؉Ճςݗۍ

ߎϔؒڷͿࣺɳʽɰ. ԵٖۓۙۆϿتڹݥڹࢍڙ

঍ۋ϶, ѺՁۚڌۋ֮ॠóݕॱʼݓ؍ڹìڷͿࣺ

ɳʽɰ. ̚ॢࣺԜۆіڏϿٮ৕ڏϿÀێ܁ॢѓॳ Ձں̿϶ě޶ʼəìں؎սەɰ. ठġইйąॠق ԴҼİۺ۞ьɵॢ۾ࣺѹÒ(slaty cleavage)ٮʌҝ رйՃॢ͎ࣷѹÒ(crenulation cleavage)À҃ۋə

ìڷͿ҃؉߯ՙॢ2ধۋԜۆѺ঍ۚڌںыؕڼں

؎սەČ, ˰͆ԴইۦݓशۆԜ٣, Ԝؓܓæę

ɰδঞąقԴьɵॢْνܓݔęĵՁġНۆ঍Ձڷ ͿॄজۚڌقࠄأॢìڷͿࣺɳʽɰ. ठġইйą ॠقԴcleavage domain (C)ęmicrolithon (M)ںĵ қॠيْν(slaty cleavage)ۆÂüںࠑ܁३҃ϸथ Œ0.07 mmͿԴϔڍܓн॥ں؎սەɰ.

2 ѥ֨Β(Fig. 3(b))əчठ܃ۚę܁ܼق֨Βۙ

ߕۆࣷĨÀ֮ॠيقफ֨սݓͿϿتںČ܁֨ࡈ

֨Βε঍Ձ३ܳəę܁ںäߝԴϿتۋ֬܃ؒԵ ę޲ۋÀەɰ. чठقԴəێ܁ॢѓॳՁں঍Ձॠ əÄԟۓۙۆ৕ڏϿٮێҙіڏϿۓۙ˞ۋě޶

ʼ϶, Եٖۋй͟ьþʽɰ. ۻъۺڷͿчठٍυ

ܼ՜֬ʽҙқۋԜɾҙқ޲ݓॠČەرԴclose polarizer قԴêڹԟڷͿǣࢍǣČەɰ. ؒԵϼڹ

ߎϔؒڷͿॄজقϔڍࠄأॢϿ֥ں҃يܳČە

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(a) No.1 (b) No.2

(c) No.3 (d) No.4

(e) No.5 (f) No.6

(g) No.7 (h) No.8

(i) No.9

Fig. 3. Photomicrographs of rock sample showing mineral composition and foliation (C) spacing

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Table 2. Mineral volumetric percentage (%) of each rock sample Sample no.

Mineral 1 2 3 4 5 6 7 8 9

Quartz 47.3 7.7 64.4 38.3 71.8 43.2 35.9 95.1 36.7

Biotite 37.3 71.0 15.9 48.6 - 36.5 - - -

Muscovite 15.4 21.3 19.7 13.1 15.6 20.3 29.0 - -

Calcite - - - - - - - - 55.1

Olivine - - - - - - - - 8.2

Pyroxene - - - - - - 9.5 - -

Feldspar - - - - - - 25.5 - -

Etc. - - - - 12.6 - - 4.9 -

ڷ϶, ठġ ইйąॠقԴ cleavage domain (C)ę

microlithon (M) ںĵқॠيْν(slaty cleavage)ۆ

Âüںࠑ܁३҃ϸथŒ0.05 mmͿԴϔڍܓн॥ں

؎սەɰ.

3 ѥ֨Β(Fig. 3(c))əܼÂ܁ʪۆڙυʪٮқśں

Íəৡԟ, ধԟ, ৕ԟۆԵٖۓۙٮҙқۺڷͿՙ͟

प॥ʼرەəÄԟۆ৕ڏϿ, ȥԟćَۆÂԾԟں

̺əіڏϿۓۙ˞ͿĵՁʼرەəڏϿठؒڷͿ

ࣺɳʽɰ. ॠݓχ, ڏϿ҃ɰəԵٖقۆॢԸ࢘ѕॳ (preferred orientation) ۋڍՃॠóě޶ʽɰ. ठġই йąॠقԴəcleavage domain (C)ęmicrolithon (M) ۆĵқۋ̤͸ॠݓ؍ݓχmicrolithon ܼԵٖۓۙ

ۆۤ߹ѕَۋڍՃॢԸ࢘ѕॳڷͿْνεۍݓॣ

սەڷ϶, ْνۆÂüںࠑ܁ॠϸथŒ0.24 mm ۋɰ.

4 ѥؒԵ֨Β(Fig. 3(d))ə1ѥؒԵ֨ΒٮÏۋ

ԵٖۋܳεۋΘəߎϔؒۋČ, Եٖۓۙۆқśڹ

1 ѥؒԵ֨ΒقҼ३ت঒ॢठۋ϶, ڙυʪ̚ॢ

ت঒ॢठۋɰ. ৕ڏϿٮіڏϿÀʴ֨قܕۦॠ϶

Ѻ঍ۚڌںы؉ڏϿۓۙ˞ۆѓॳՁۋ঍Ձʽìڷ Ϳ҃ۍɰ. ठġইйąॠقԴcleavage domain (C)ę

microlithon (M) ںĵқॠيْν(slaty cleavage)ۆ

Âüںࠑ܁३҃ϸथŒ0.12 mmͿԴϔڍܓн॥ں

؎սەɰ.

5 ѥؒԵ֨Β(Fig. 3(e))əԵٖۓۙ˞ۋɰՙąć ÀҝқϼॠݓχۻъۺڷͿҋ०Ը঍ࢗεۋΘČ

қपॠ϶, іڏϿÀأÂܕۦॠəԵٖठؒۋɰ. Ā

܁ठؒۋǣۿߤѺՁۚڌںыڹ۾ࣺؒقԴܳͿ

ě޶ʼəҝ࣊ϼġНۍandalusiteʪě޶ʽɰ. ܓς ݗٍ՚ْνۆÂüںࠑ܁३҃ϸ0.85 mm ۋɰ.

6 ѥؒԵ֨Β(Fig. 3(f))ə֮ॢॄজεыڹߎϔؒ

ۋɰ. ԵٖۓۙεۙՃ০ě޶ॠϸۙ঍ۆ঍ࢗεÀ ݓČەݓχ, ŔǴҙ঍ࢗəۻъۺڷͿ֮ॠóࣷթ

ʼرەə঍Ԝںě޶ॣսەəʚ, ۋə֮ॢॄজۆ

ݒäͿ҇սەɰ. ۻߕۺڷͿ৕ڏϿٮіڏϿÀ

ě޶ʼČێҙՙսۆþڏϿʪě޶ʼ϶, ْνۆÂ üڹथŒ0.08 mmۋɰ.

7 ѥؒԵ֨Β(Fig. 3(g))əυŔυۆěۓقۆ३

঍ՁʽؒϕڷͿԴؒԵۆԟڹٍȥԟقԴؒȥԟں

̺Čەڷ϶, शϸقɰսۆşėۋܕۦॢɰ. ۋşė ڹॄজۚڌقۆ३ۤԵ˞ۋӇ܋ǣÂėÂڷͿ߸

܁ʽɰ. ԵٖęۤԵф৅ԵۋܳεۋΘČێҙ

৕ڏϿÀەəۋؒԵ֨ΒəԵٖ؋ԓؒ(dacite)ۋ ɰ. Եٖ؋ԓؒڹԜʂۺڷͿߎϔؒ҃ɰॄজٮࠞ

֩قÌॢՁݗں҃يܳČەɰ. ठġইйąॠقԴ əأॠóْνÀьɵॠəìߌͤ҃ۋǣ֬܃ؒठ قԴəࢍڙ঍ۆşėۋѕَॠəتԜں۞҃ۋČ

ەɰ. cleavage domain (C)ęmicrolithom (M)ں̤͸

ॠóĵқॣχࢂْνۆьɵۋই۹ॠݓə؍ڷǣ

थŒ0.45 mmͿԴϔڍؾՁॠɰ.

8 ѥؒԵ֨Β(Fig. 3(h))əۻ঍ۺۍőؒڷͿԴ

Եٖۓۙ˞ۋܓςݗں҃ۋ϶, ҋ०Ը঍ࢗʪйأॠ

(7)

Table 3. Average spacing and morphological classification of foliation Specimen

no.

Average spacing of foliation (mm)

Morphological classification of foliation (after powell, 1979)

1 0.07 Disjunctive, rough-moderately rough

2 0.05 Disjunctive, rough-moderately rough

3 0.24 Continuous, coarse

4 0.12 Disjunctive, rough-moderately rough

5 0.85 Continuous, coarse

6 0.08 Disjunctive, rough-moderately rough

7 0.45 Continuous, coarse

8 1.31 Continuous, coarse

9 0.50 Continuous, coarse

ݓχ۞ǣࢍǣČەɰ. ॠݓχԵٖۓۙ˞قࣷʴՙ ġۋäۆьԦॠݓ؍əìڷͿ҃؉, Եٖۋ܁߻ʽ

঳قٽҙͿҙࢢڿͳںψۋыݓ؍ؕäǣ, Č٣ق Դ۹٣ڷͿѺॣ˺Ā܁ĵܓقѺۋÀԦşݓ؍ؕ

ڼں߸܁ॣսەɰ. ۋəőؒۋؓͳقۆ३ԦՁʼ ş҃ɰəԵٖؒϕۋǣَսԵٖϕقۆ३ԴԦՁ ʽìڷͿ҃ۋ϶, ێъۺۍőؒقҼॠϸÌʪÀ

أॣìڷͿࣺɳʽɰ. ْνۆथŒÂüڹ1.31 mmͿ

ࠑ܁ʼؽɰ.

9 ѥؒԵ֨Β(Fig. 3(i))ə֮ʪÀǰڹĖقԴ঍Ձ ʽʮͿυۋ࣡ÀَѺՁںыČSiO 2 Àࠞ࣊ॠيԦ ՁʽԵধőԓّؒ(limesilicate)ۋɰ. ۻъۺڷͿқ চӆۆѓ३ԵۋܳͿқपॠČەڷ϶, ێҙԵٖۓ

ۙ˞ۋьþʽɰ. ̚ॢÇ͊Եʪьþʼəìں؎

սەɰ. ْνۆÂüڹ0.50 mmͿࠑ܁ʼؽɰ. Table 2 əইйąě޶قԴࠑ܁ʽ֨ΒѻġНҙक़Ҽε

܁νॢशۋ϶, Table 3ڹْνۆÂüę঍ࢗॡۺ

қΪεǣࢍǶशۋɰ.

ᱡᄡᖒ♕ᱢᦵ᮹⣮⪵ࠥ

ؒԵۆॄজəؒԵۆՁۍęݓݗ֨ʂʴ؋ýڹ

ݓĵܓڏʴۆĀęͿĀ܁ʼəĵՁġНęɳَۆ

ьɵ܁ʪقۆ३ࡾóٖॳںыəɰ. ŔۋڮəؒԵ ںĵՁॠəÒѻġН˞ۆজॡۺъڿąͿфНν

ۺॄজ՚ʪق޲ۋÀەڷ϶, ؒъǴقԴɳَڹ

ҝŒݗॠóқपॠČ࣊սՁʪԴͿɰβş˺Лۋ ɰ. ˰͆Դؒъۆॄজʪəؒܛęԓ߻ݓ۾ق˰͆

ѺজÀ֮ॠş˺ЛقԺćф֨ė֨قəʂԜؒъ ۆॄজ࣢Ձں߿қ০ۋ३ॣज़څÀەɰ.

Ųྜྷ᳑ᖒŝ⣮⪵ࠥ᮹ᔢšᖒ

ġНڹܛΪق˰͆Ͽ֟ԜʂąʪÀɰβş˺Лق

ॄজقʂ३ԴʪŔъڿۋɰβóǣࢍǦɰ. Gupta and Rao (2001) əőؒ, জÌؒфইИؒںʂԜڷͿ

֪ԸॢġНęॄজقۆ३ѺݗʽġНۆҼۍজॡ ۺॄজݓսεćԓॠيԵٖۆ॥ڮ͟ۋؒԵۆॄ

জʪقٖॳںй࠘əìںঝۍॠٕɰ. ٍ҆ĵقԴ əؒԵۆইйąě޶قԴصڹĵՁġНѻҙक़Ҽ (Table 2) ٮॄজۆěćε؎؉҃şڦॠيॄজق

ÌॢԵٖęڏϿΪقʂॠيԜěՁںқԵॠٕɰ.

ॄজʪÀÀ֮ۤॠóܓԐʽߎϔܼؒ2ѥ֨Βə

7.7% ۆԵٖ॥͟ڷͿϔڍǰڹÉں҃ۋČ, ڏϿΪ À92.3%ۆϔڍȭڹÉں޲ݓॠČەəʚ, ؘۼۆ

чठқԵقԴʪşց॰ˢۋॄজÀ֮ॠيчठٍυ

ܼ՜֬ʽҙқۋψ؉ġНʴ܁ۋۋΘرݓݓ؍ؕ

ş˺ЛڷͿ߸܁ʽɰ.

ۻъۺڷͿÌʪÀȭČॄজ܁ʪÀǰںս΀ॄজ

ق Ìॢ ԵٖՁқۋ ψڹ ìڷͿ ǣࢍǮڷ϶(Fig.

(8)

(a) Quartz (b) Mica

Fig. 4. Relationship between average rebound number of Schmidt hammer and volumetric percentage of quarts and mica

Fig. 5. Relationship between average rebound number of Schmidt hammer and spacing of foliation

4(a)), ÌʪÀǰČॄজ܁ʪÀȭںս΀ॄজقأॢ

ڏϿΪՁқۋψڹìڷͿǣࢍǮɰ(Fig. 4(b)).

ᩞญeĊŝ⣮⪵ࠥ᮹ᔢšᖒ

чठě޶Āęقۆॠϸٍ҆ĵݓًقқपॠə

äۆϿ˜ؒԵ֨ΒقԴْνÀьɵॠČەəìں

؎սەڷ϶, ьɵॢْνۆѓॳՁڹٍĵݓًۆ

ۻъۺۍْνۆѓॳՁęҼİۺ۞ێ࠘ॠČەɰ.

ۋəٍĵݓًǴقێ܁ॢѓॳڷͿڿͳۋۚڌॠٕ

ڼں҃يܵɰ. ॠݓχؒܛѻͿْνۆÂüę঍ࢗ

ॡۺ࣢Ձڹ޲ۋε҃ۍɰ. ؒԵۆॄজʪфÌʪٮ

ْνÂüęۆԜěՁںԕट҃ϸॄজʪÀȭČÌʪ Àǰںս΀ْνۆÂüۋܓнॠóǣࢍǮڷ϶(Fig.

5), Ā܁ćսR ² ʪ0.92Ϳȭڹìں؎սەɰ. ۋə

ٍ҆ĵݓًǴقəşڙؒۆ޲ۋÀ̤͸ॢؒԵŔ

(9)

(a) Quartz (b) Mica

Fig. 6. Relationship between spacing of foliation and volumetric percentage of quarts and mica

Νۋܕۦॠ϶ۋ˞ڹԴͿɰδْνÂüں҃ۋş

˺ЛڷͿ३Եʽɰ. ॄজˣśقʂॢ֨ΒۆْνÂ üںԕट҃ϸHWۆąڍə0.050.12 mm, HW-MW ۆąڍə0.240.50 mm, MWə0.85, SWə1.31 mm ͿǣࢍǦɰ. ێъۺڷͿࢢȇۋǣԐϸæԺڹ

ٍ҆ĵݓًęÏۋॢ܁ʽݓًقԴۋΘرݓş˺

ЛقʴێॢݓĵܓڏʴںыڹąڍÀψɰ. ˰͆Դ

ʂԜݓًقқपॠəؒܛں܁ঝ০ĵқॠϸĵՁġ НęْνÂü࣢ՁںۋڌॠيॄজʪεĀ܁ॠəʚ

ࡾóʪړۋʽɰ.

Ųྜྷ᳑ᖒŝᩞญeĊ᮹ᔢšᖒ

ġНܓՁęɳَьɵ܁ʪÀॄজʪقٖॳںй࠘

əܼڅॢڅՙۋݓχۋ˞ÂۆԜěՁڹؒܛυɰ

޲ۋÀەںսەɰ. ॠݓχٍ҆ĵۆʂԜۍܙڹ

ًٖقқपॠə۹ѺՁࣅۺؒęÏۋʴێॢݓĵܓ ڏʴںыڹؒъۆąڍْνۆьɵ܁ʪٮĵՁġ НęۆԜěՁۋȭóǣࢍǦɰ. ْνۆÂüڹڏϿ ۆ॥͟قъҼͻॠČ, Եٖۆ॥͟ęə۞ҼͻॠČ

ەɰ(Fig. 6).

đು

҆ȦЛقԴəܙڹًٖقԴʴێॢݓĵܓڏʴں

ыڹìڷͿۍ܁ʼə۹ѺՁࣅۺؒںʂԜڷͿؒъ ۆॄজԜࢗقʂॢইۤܓԐٮইйąě޶ںࣀॠ يġНܓՁфْνÂüۋ޲ѻॄজقй࠘əٖॳ ںқԵॠٕɰ.

1. ٍĵʂԜݓًۆफ300يm ۼࠄԐϸǴقəܳ

қपؒԵۍߎϔؒęڏϿठؒ, Եٖठؒ, Ā܁ݗ

іڏؒ, őؒ, ŔνČěۓؒۍԵٖ؋ԓؒˣ6ܛ ۆؒԵۋқपॠČەڷ϶, ؒܛق˰͆ॄজʪٮ

ÌʪÀɰβóǣࢍǦɰ.

2. чठě޶Āęقۆॠϸؒܛق˰͆ԵٖęڏϿ ΪۆқपقԴ޲ۋε̤͸ۋ҃ۋČەɰ. ߎϔؒ

ۆąڍϿؒۆܛΪقşۍॠيԵٖęڏϿۆ

ߕۺҼÀɵνǣࢍǣəʚ, ॄজقۆॠيчठ

ԜйঝۍġНۋψؕʏ2ѥąڍε܃ٽॠϸ

ʂߕͿɰδؒԵۆąڍٮʴێॠóԵٖ॥ڮ͟

ۋȭںս΀ÌʪəȭČॄজʪəǰóǣࢍǣ϶, ڏϿΪۆ॥͟ۋȭںս΀ÌʪəǰČॄজʪə

ȭóǣࢍǦɰ.

(10)

3. ْνۆÂüڹॄজʪÀȭČÌʪÀǰںս΀

ܓнॠóқपॠČەڷ϶ԜěՁʪϔڍȭó

ǣࢍǦɰ. ŔۋڮəٍĵʂԜؒԵۋʴێݓĵܓ ڏʴॠقԴşڙؒۆ޲ۋÀ̤͸॥قşۍॠə

ìڷͿࣺɳʽɰ.

4. ˰͆Դٍ҆ĵʂԜؒԵڹԵٖۆ॥͟ۋȭںս

΀ْνÂüۋȉČ, ڏϿۆ॥͟ۋȭںս΀ܙڹ

ْνÂüں҃ۍɰ.

qᔍ᮹ɡ

ٍ҆ĵə2012țʪİگęॡşցҙۆۦڙڷͿ

ॢĶٍĵۦɳۆ ‘ėė҄ݓ؋ۻşցÒьԐغ(2012 M3A2A1050985)’ ۆݓڙںы؉սॱʼؽ֥ɦɰ.

ₙŁྙ⨭

1. Cho, Y.H., Lim, D.S., Chun, B.S. (2010), “A case study on the slope collapse and reinforcement method of the phyllite slope”, Journal of Korea Geo-Environmental Society, Vol. 11, No. 8, pp.

83-93.

2. Gupta, A.S., Rao K.S. (2001), “Weathering indices and their applicability for crystalline rocks”, Bulletin of Engineering Geology and the Enviro- nment, Vol. 6, No. 3, pp. 201-221.

3. ISRM (1978), “Suggested methods for the quant itative description of discontinuities in rock masses”, International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, Vol. 15, pp. 319-368.

4. Kim, H.S., Cho, D.S. (1993), “Genesis of talc deposits in the Chungju area, Korea”, Journal of Petrological Society of Korea, Vol. 2, No. 2, pp.

95-103.

5. Koçkar, M.K., Akgün, H. (2003), “Methodology for tunnel and portal support design in mixed limestone, schist and phyllite conditions: a case study in Turkey”, International Journal of Rock

Mechanics & Mining Sciences, Vol. 40, pp.

173-196.

6. Koo, H.B., Kim, S.H., Kim, S.H., Lee, J.Y.

(2008), “A study on jointed rock mass properties and analysis model of numerical simulation on collapsed slope”, Journal of Korean Geotechnical Society, Vol. 24, No. 5, pp. 65-78.

7. Kwon, Y.I., Jin, M.S. (1974), “Explanatory text of the geological map of Cheong Ju sheet (1:

50,000)”, Korea Institute of Geoscience and Mineral Resources.

8. Lee, B.J., Kim, D.H., Choi, H.I., Kee, W.S., Park, K.H. (1996), “Explanatory text of the geological map of Daejeon sheet(1:250,000)”, Korea Institute of Geoscience and Mineral Resources.

9. Lee, S.H., Kim, M.K. (1997), “Lithogeochemical characteristics of the granitic rocks in Chungju- Chongju area”, Journal of Industrial Science, Chongju University, Vol. 15, pp. 109-116.

10. Lee, S.K., Son, W.H., Jeong, S.H. (2007), “A study on over-break characteristics of tunnel in phillite rock masses”, Journal of Geological Society of Korea, Vol. 2007, No. 2007, pp. 169.

11. Park, B.S., Cho, H., Youn, S.P., Lee, S.H. (2011),

“Case study on stability analysis of phyllite rock slopes in national road construction”, International Journal of Geo-Engineering, Vol. 3, No. 3, pp.

41-52.

12. Park, H.I., Lee, J.D., Jeong, J.G. (1977), “Geological map of Korea : Yuseong sheet(1:50,000)”, Korea Institute of Geoscience and Mineral Resources.

13. Powell, C.McA. (1979), “A morphological class- ification of rock cleavage”, Tectonophysics, Vol.

58, No. 1-2, pp. 21-34.

14. Santi, P.M. (2006), “Field methods for characterizing weak rock for engineering”, Journal of Environmental and Engineering Geoscience, Vol. 6, No. 1, pp.

1-11.

15. Shin, K.J., Kim, S,K., Kim, J.H. (2003), “A case

study of failure behavior in phyllite slope of

developed rock cleavages”, Korean Society for

Rock Mechanics Conference, pp. 121-134.

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16. Tanyas, H., Ulusay, R. (2013), “Assessment of structurally-controlled slope failure mechanisms and remedial design considerations at a feldspar open pit mine, western turkey”, Engineering Geology, Vol. 155, pp. 54-68.

17. Tinoco, F.H., Salcedo, D.A. (1981), “Analysis of

slope failures in weathered phyllite”, ISRM Inter- national Symposium, Japan, pp. 8.

18. Um, J.K. (2008), “A reinforcement case of slope

failure by fractured zone of schist and gneiss”,

Journal of Korean Geotechnical Society, Vol. 24,

No. 8, pp. 34-41.

Effect of geological characteristics on differential weathering of low-graded metasedimentary rock slopes

*Corresponding author: Yong-Seok Seo E-mail: [email protected]

Received May 6, 2013; Revised May 15, 2013;

Accepted May 21, 2013

୨ැֽ  ȵছ૳জ  ȵହࡣ෭ 

Ҽধڙ ॢĶսۙڙėԐ,XBUFSٍĵڙ ٍĵڙ

܁ধڙ ߿Қʂॡİݓĵঞąęॡę İս

Ҽধڙ ʂۻʂॡİݓъѓۦėॡę İս

Effect of geological characteristics on differential weathering of low-graded metasedimentary rock slopes

Hae-Geun Jeong

, Yong-Seok Seo

*, Myung-Hyeok Ihm

K-water Institute, Korea Water Resources Corporation, Researcher

Department of Earth and Environmental Sciences, Chungbuk National University, Professor

Department of Geotechnical Engineering for Disaster Prevention, Daejeon University, Professor

Keywords: Low-graded metasedimentary rocks, Weathering grade, Mineral composition, Spacing of foliation, Schmidt hammer test

ߣ΀ ҆ȦЛقԴəߎϔؒںܼ֮ڷͿ۹ѺՁࣅۺؒΪق՚ॠəؒԵںʂԜڷͿؒԵॡۺ࣢ݜęॄজʪۆԜěՁقʂॠي

қԵॠٕɰইۤݓݗܓԐεࣀॠيؒԵۆॄজʪεĀ܁ॠٕČ ĵՁؒԵۆÌʪÉں߸܁ॠşڦॠي֙й࣡३Ϣࢬ֟࣡ε

֬֨ॠٕɰÒ֨Βۆইйąчठě޶ںࣀॠيܳĵՁġНۆҙक़ҼٮْνۆÂüںࠑ܁ॠٕɰؒԵ֨ΒۆইйąқԵ

ĀęقۆॠϸॄজʪÀǰںս΀ॄজقÌॢԵٖՁқۋψČ ॄজʪÀȭںս΀ॄজقأॢڏϿՁқۋψڹìڷͿǣࢍǮɰ

̚ॢْνÂüۋܙںս΀ÌʪəǰČॄজʪəȭڹìڷͿǣࢍǮɰ

ܳڅر۹ѺՁࣅۺؒ ॄজʪ ġНܓՁ ْνÂü ֙й࣡३Ϣࢬ֟࣡

$PQZSJHIU ,PSFBO5VOOFMMJOHBOE6OEFSHSPVOE4QBDF"TTPDJBUJPO

ᕽು

ڍνǣ͆ۆҚʴҙقԴǫʴҙεÀͿݓβϸԴқ पॠə٢ߎʂݓًقəݓݗॡۺڷͿ۹ѺՁࣅۺؒ

Ϊق՚ॠə۾ࣺؒ, ߎϔؒ, ठؒˣęԵধؒ̚ə

ԵধőԓّؒˣɰتॢؒԵۋқपॢɰ. ۋ˞ݓࠗ

ڹęäս޲ͻقèࠚѺՁۚڌڷͿ֥čфɳࠗ

ˣۋьɵॠČەرėॡۺڷͿϔڍҝ؋܁ॢݓъ ق՚ॢɰ.

۹ѺՁࣅۺؒΪəϿؒęѺՁфѺ঍ۚڌۆ޲ۋ قۆॠيْν, ѹÒϸ, ֥čфɳࠗˣۆьɵ܁ʪÀ

޲ۋε҃ۋ϶, ۋ͠ॢ޲ۋəݓъǴقԴ޲ѻॄজ ۆڙۍۋʼ϶, ؒԵۆÌʪфǴĵՁ۹ॠ, ॄজࢹࠗ

ۆьɵˣڷͿۋر܋Ԑϸۋǣࢢȇ֨ė֨ңĨۆ

Fig. 1. Regional geologic map of the study area (from Lee et al., 1997)

ڙۍۋʽɰ.

Santi (2006) əইۤقԴ۹ѺՁࣅۺؒˣٍأؒ

ۆ࣢ՁںşۦॠيқΪॣսەəşܵęۺۼॢ

֨ॹѓѪں܃֨ॠٕڷ϶, йĶǴقԴٍأؒۋқ पॠəݓʪ, ؒԵܛΪфėॡۺ࣢Ձں܁νॠي

ьशॠٕɰ. Lee et al. (2007)ڹߎϔؒقьɵॠə

ɳࠗНݗںؒԵ·ġНॡۺڷͿқΪॠČ, ۋ˞ۆً

ॡۺ࣢ՁںٍĵॠيԐϸфࢢȇˣۆًॡۺ३Ե قۋڌॣսەʪ΀܁͟ۺۍًॡ܁սε܃֨ॢ

цەɰ. ڍνǣ͆قԴ۹ѺՁࣅۺؒΪقʂॢėॡ ۺٍĵəʪͿæԺęěʹॠيąҙČ՚ʪͿ, ߔڙ- ԜܳÂČ՚ʪͿ, ٢ߎʂεࣀęॠəĶʪˣقԴԐ ϸфࢢȇۆ؋܁ՁқԵқآۆٍĵÀɰսۋΘر ݓČەɰ(Shin et al., 2003; Koo et al., 2008; Um, 2008; Cho et al., 2010). ٽĶقԴʪߎϔؒқपݓً

ۆ ԐϸңĨق ʂॢ ԐͻÀ ɰս ҃ČʼČ ەɰ (Tinoco and Salcedo, 1981; Park et al, 2011; Tanyas and Resat, 2013). Koçkar and Akgün (2003) ڹ۹ѺՁ ࣅۺؒқपݓًقԴْνьɵęॄজͿۍ३ٍأজ

ʽݓъقæԺʼəࢢȇۆÚĵҙ҃Ìęěʹʽ

Ԑͻεьशॢцەɰ.

۹ѺՁࣅۺؒۆॄজεݓѕॠəܳڅۍڷͿəѺ Ձۚڌʴ؋ԦՁʼəॄজقࠄأॢĵՁġНęٍأ ϸں঍ՁॠəْνÀەɰ. ҆ȦЛڹߎϔؒۋ۞

ьɵॠə۹ѺՁࣅۺؒݓًۆԐϸقԴইۤܓԐٮ

ইйąě޶ںࣀॠيġНܓՁфْνÂüۋ޲ѻ

ॄজقй࠘əٖॳںқԵॠəʚŔЀۺۋەɰ.

ইۤقԴISRM (1978)قԴ܃֨ॢॄজʪεۋڌॠ يؒъۆॄজ܁ʪεܓԐॠČ֙й࣡३Ϣεۋڌॠ يÌʪεࠑ܁ॠ϶, ԴͿɰδؒܛںԸ࢘ॠيߪ

9 ÒۆؒԵ֨Βε޽ࠄॠي֬ǴقԴчठں܃ۚॢ

঳, ठġইйąě޶ں֬֨ॠيġНܓՁфْν

ьɵԜࢗε܁͟ۺڷͿқԵ॥ڷͿ׆۹ѺՁࣅۺؒ

ΪۆؒԵॡۺ࣢ݜęॄজʪٮۆԜěՁںêࢹॠČ

ۙॢɰ.

ḡḩ

ٍ҆ĵݓًقəߎϔؒ, ڏϿठؒ, Եٖठؒ, Ā܁

ݗіڏؒ, őؒˣۋқपॠČەڷ϶, ۋ˞ڹߔܳʪ फ(Kwon and Jin, 1974)قԴə֨ʂйԜۆ৕ڏϿ

ठؒڷͿ, ڮՁʪफ(Park et al., 1977)قԴəČԦʂ

Fig. 2. Panoramic view and the results of face mapping of the study area. The numbers indicate sampling locations for microscopic observation

Table 1. Rock name, weathering grade and average rebound number of Schmidt hammer determined in the field survey Observation

no.

Rock name

Weathering Grade (ISRM, 1978)

Ave. rebound number of Schmidt hammer

1 Phyllite HW 10>

2 Phyllite HW 10>

3 M-schist MW-HW 28

4 Phyllite HW 10>

5 Q-schist MW 40

6 Phyllite HW 10>

7 Dacite MW-HW 31

8 Quartzite SW 56

9 Dolomite MW-HW 26

࠮ҵͿ-١βʪҼ֟şۆॳԓνࠗķق՚ॠə৕ڏϿ

іڏϿȥνԵठؒڷͿܓԐʼČەɰ(Fig. 1). ۋݓ

ࠗ˞ڹ ʂߕͿ Қʴ(60°65°)ܳॳę ǫʴ(40°

45°) ąԐεÀݓ϶ݓًۺڷͿ֥čĵܓε҃ۍɰ.

߿ܳݓًںܼ֮ڷͿқपॠəॳԓνࠗęʂॳԓ őؒࠗڹٍ҆ĵݓًūݓҚʴ-ǫԴѓॳۆ̿ε঍

ՁॠϸԴқपॠČەɰ. ̚ॢॳԓνࠗęʴ֨ʂͿ

ʂҼʼəʂॳԓőؒࠗڹڮіԟں̿϶ʂҙқۦĀ

୨ැֽ ȵছ૳জ ȵହࡣ෭

Ҽধڙ ॢĶսۙڙėԐ,XBUFSٍĵڙ ٍĵڙ

ߣ΀ ҆ȦЛقԴəߎϔؒںܼ֮ڷͿ۹ѺՁࣅۺؒΪق՚ॠəؒԵںʂԜڷͿؒԵॡۺ࣢ݜęॄজʪۆԜěՁقʂॠي

қԵॠٕɰইۤݓݗܓԐεࣀॠيؒԵۆॄজʪεĀ܁ॠٕČ ĵՁؒԵۆÌʪÉں߸܁ॠşڦॠي֙й࣡३Ϣࢬ֟࣡ε

֬֨ॠٕɰÒ֨Βۆইйąчठě޶ںࣀॠيܳĵՁġНۆҙक़ҼٮْνۆÂüںࠑ܁ॠٕɰؒԵ֨ΒۆইйąқԵ

ĀęقۆॠϸॄজʪÀǰںս΀ॄজقÌॢԵٖՁқۋψČ ॄজʪÀȭںս΀ॄজقأॢڏϿՁқۋψڹìڷͿǣࢍǮɰ

̚ॢْνÂüۋܙںս΀ÌʪəǰČॄজʪəȭڹìڷͿǣࢍǮɰ

ܳڅر۹ѺՁࣅۺؒ ॄজʪ ġНܓՁ ْνÂü ֙й࣡३Ϣࢬ֟࣡

$PQZSJHIU ,PSFBO5VOOFMMJOHBOE6OEFSHSPVOE4QBDF"TTPDJBUJPO

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