Mobile QR Code QR CODE : Journal of the Korean Society of Civil Engineers

  1. ์ข…์‹ ํšŒ์›โ€ค๋ถ€๊ฒฝ๋Œ€ํ•™๊ต ์Šค๋งˆํŠธ์ธํ”„๋ผ๊ธฐ์ˆ ์—ฐ๊ตฌ์†Œ ์ „์ž„์—ฐ๊ตฌ์› (Pukyong National Universityโ€คdhyun@pknu.ac.kr)
  2. ์ข…์‹ ํšŒ์›โ€ค๊ต์‹ ์ €์žโ€ค๋ถ€๊ฒฝ๋Œ€ํ•™๊ต ํ•ด์–‘๊ณตํ•™๊ณผ ๊ต์ˆ˜ (Corresponding Authorโ€คPukyong National Universityโ€คyuntkim@pknu.ac.kr)



ํ”ผ์••, ์—ฐ์•ฝ์ง€๋ฐ˜, ๋™์ˆ˜๊ฒฝ์‚ฌ, ํŽ˜๋†€ํ”„ํƒˆ๋ ˆ์ธ
Artesian pressure, Soft ground, Hydroulic gradient, Phenolphthalein

1. ์„œ ๋ก 

ํ”ผ์••(artesian pressure)์ด๋ž€ ์•”๋ฐ˜์ด๋‚˜ ์ ํ† ์ธต๊ณผ ๊ฐ™์€ ๋ถˆํˆฌ์ˆ˜์ธต ๋˜๋Š” ํˆฌ์ˆ˜๊ณ„์ˆ˜๊ฐ€ ๋งค์šฐ ์ž‘์€ ์ง€์ธต ์‚ฌ์ด์—์„œ ์ •์ˆ˜์••๋ณด๋‹ค ๋” ํฐ ์••๋ ฅ์„ ๋ฐ›๊ณ  ์žˆ๋Š” ์ƒํƒœ๋ฅผ ๋งํ•œ๋‹ค. ์ด๋•Œ, ์••๋ ฅ ๋˜๋Š” ์ˆ˜๋‘์ฐจ์— ์˜ํ•ด ๋ฐœ์ƒํ•œ ํ”ผ์••์ด ์กด์žฌํ•˜๋Š” ๋Œ€์ˆ˜์ธต์„ ํ”ผ์••๋Œ€์ˆ˜์ธต(confined aquifer)์ด๋ผ ํ•œ๋‹ค. ๋งŽ์€ ์—ฐ๊ตฌ์ž๋“ค์ด ๋ถ€์‚ฐ ๋‚™๋™๊ฐ• ํ•˜๊ตฌ ์ง€์—ญ์—์„œ ํ”ผ์••์— ๋Œ€ํ•œ ์ง€๋ฐ˜์กฐ์‚ฌ์™€ ์—ฐ๊ตฌ๋ฅผ ์ˆ˜ํ–‰ํ•œ ๊ฒฐ๊ณผ, ๋ถˆํˆฌ์ˆ˜์ธต์ธ ์ ํ† ์ง€๋ฐ˜๊ณผ ํ•˜๋ถ€ ์•”๋ฐ˜์ธต ์‚ฌ์ด์— ์กด์žฌํ•˜๋Š” ๋Œ€์ˆ˜์ธต์—์„œ ํ”ผ์••์ด ์ž‘์šฉํ•˜๋Š” ๊ฒƒ์œผ๋กœ ์กฐ์‚ฌ๋˜์—ˆ๋‹ค(Han and Yu, 1999; Kim et al., 2002; Kim et al., 2006; Kim et al., 2011).

ํŠนํžˆ, ๋ถ€์‚ฐ ๋‚™๋™๊ฐ• ํ•˜๊ตฌ ์ง€์—ญ์€ ์‚ฐ์œผ๋กœ ๋‘˜๋Ÿฌ ์Œ“์—ฌ ์žˆ๋Š” ์ง€ํ˜•์  ํŠน์„ฑ๊ณผ ๋”๋ถˆ์–ด ๋ถˆํˆฌ์ˆ˜์ธต์ธ ๋Œ€์‹ฌ๋„ ์—ฐ์•ฝ์ ํ† ์ธต์ด ๋„“๊ฒŒ ๋ถ„ํฌํ•˜๊ณ  ์žˆ์–ด ๋ณด๋ง(boring) ์ž‘์—… ๋ฐ ํ˜„์žฅ์กฐ์‚ฌ๋‚˜ ์ง€๋ฐ˜ ๊ตด์ฐฉ ๊ณต์‚ฌ์—์„œ ํฌ๊ณ  ์ž‘์€ ํฌ๊ธฐ์˜ ํ”ผ์••์ด ๊ด€์ธก๋˜๊ณ  ์žˆ๋‹ค. ๋ถ€์‚ฐ ๋‚™๋™๊ฐ• ํ•˜๊ตฌ์— ์œ„์น˜ํ•œ ๊ฐ•์„œ๊ตฌ, ๋ถ€์‚ฐ์‹ ํ•ญ, ๊ฐ€๋•๋„, ์—์ฝ”๋ธํƒ€์‹œํ‹ฐ ๋ฐ ์–‘์‚ฐ ๋“ฑ ๋‹ค์–‘ํ•œ ์ง€์—ญ์„ ์กฐ์‚ฌํ•œ ๊ฒฐ๊ณผ, ์•ฝ 1.2 m ~ 5.8 m ํฌ๊ธฐ์˜ ํ”ผ์••์ด ๊ด€์ธก๋˜์—ˆ๋‹ค(Baek, 2002; Chung et al., 2010; Heo, 2003; Kim et al., 2008a; Kim et al., 2011).

ํ”ผ์••์ด ์กด์žฌํ•˜๋Š” ์—ฐ์•ฝ์ง€๋ฐ˜์˜ ์œ ํšจ์‘๋ ฅ์€ ํ”ผ์••์˜ ํฌ๊ธฐ๋งŒํผ ์ž‘์€ ์ƒํƒœ๋กœ ์••๋ฐ€๋˜์–ด ์žˆ๊ธฐ ๋•Œ๋ฌธ์— ์—ฐ์•ฝ์ง€๋ฐ˜ ์••๋ฐ€์นจํ•˜๋Ÿ‰ ๊ณ„์‚ฐ์—์„œ ํ”ผ์••์„ ๊ณ ๋ คํ•˜์ง€ ์•Š์œผ๋ฉด ์„ค๊ณ„๋ณด๋‹ค ํฐ ์นจํ•˜๊ฐ€ ๋ฐœ์ƒ๋  ์šฐ๋ ค๊ฐ€ ์žˆ๋Š” ๊ฒƒ์œผ๋กœ ์•Œ๋ ค์ ธ ์žˆ๋‹ค(Kim and Do, 2010; Kim et al., 2018; Yun and Kim, 2016).

๋˜ํ•œ, ํ”ผ์••์ด ์ž‘์šฉํ•˜๋Š” ๊ฒฝ์šฐ ์ ํ†  ํ•˜๋ถ€ ์ง€๋ฐ˜์—๋Š” ์—ผ๋ถ„์ด ๋น ์ ธ๋‚˜๊ฐ€๋Š” ์šฉํƒˆ(leaching) ํ˜„์ƒ์ด ๋ฐœ์ƒํ•  ์ˆ˜ ์žˆ๋‹ค. Yun et al.(2016)์€ ์‹ค๋‚ด์‹คํ—˜์„ ํ†ตํ•ด ํ”ผ์••์ด ์ž‘์šฉํ•˜๋Š” ์ง€์ธต์˜ ์‹œ๋ฃŒ๋ฅผ ์ฑ„์ทจํ•˜์—ฌ X-์„  ํ˜•๊ด‘๋ถ„์„๊ธฐ(X-ray flourescence spectrometry, XRF)๋ฅผ ์ด์šฉํ•˜์—ฌ ๋ถ„์„ํ•œ ๊ฒฐ๊ณผ, ํ”ผ์••์ด ์ž‘์šฉํ•˜๋Š” ์ง€๋ฐ˜์— ์šฉํƒˆ ํ˜„์ƒ์ด ๋ฐœ์ƒํ•œ ๊ฒƒ์„ ์‹คํ—˜์ ์œผ๋กœ ํ™•์ธํ•˜์˜€๋‹ค. ์—ผ๋ถ„์ด ๋น ์ ธ๋‚˜๊ฐ€๋ฉด ์–‘์ด์˜จ์˜ ์œ ์‹ค๋กœ ์ธํ•ด ์ ํ†  ์ž…์ž๊ฐ„์˜ ํ™”ํ•™์  ๊ตฌ์กฐ๊ฐ€ ์ทจ์•ฝํ•ด์ง€๋ฏ€๋กœ ์••์ถ•์„ฑ์— ์˜ํ–ฅ์„ ๋ฏธ์น˜๊ฒŒ ๋œ๋‹ค. Kim and Do(2010)๋Š” ๋ถ€์‚ฐ ํ˜„์žฅ์˜ ์ ํ†  ์‹œ๋ฃŒ๋ฅผ ์ฑ„์ทจํ•˜์—ฌ ์‹ค๋‚ด์‹คํ—˜์„ ํ†ตํ•ด ์••๋ฐ€์‹œํ—˜์„ ์ˆ˜ํ–‰ํ•œ ๊ฒฐ๊ณผ ์—ผ๋ถ„ ์šฉํƒˆ์ด ๋ฐœ์ƒํ•  ๊ฒฝ์šฐ ์••์ถ•์ง€์ˆ˜๊ฐ€ ์ปค์ง€๊ณ  ๊ฐ„๊ทน๋น„ ๋ฐ ์„ ํ–‰์••๋ฐ€ํ•˜์ค‘์ด ๊ฐ์†Œํ•œ๋‹ค๋Š” ๊ฒƒ์„ ์‹คํ—˜์„ ํ†ตํ•ด ๋ฐํžŒ ๋ฐ” ์žˆ๋‹ค.

DCM (deep cement mixing) ๊ณต๋ฒ•์€ ์‹ฌ์ธตํ˜ผํ•ฉ์ฒ˜๋ฆฌ ๊ณต๋ฒ•์ด๋ผ๊ณ ๋„ ํ•œ๋‹ค. ์ ์„ฑํ† , ์‚ฌ์งˆํ† , ์œ ๊ธฐ์งˆํ†  ๋“ฑ ์—ฐ์•ฝ์ง€๋ฐ˜๋‚ด์— ์‹œ๋ฉ˜ํŠธ์™€ ๋ฌผ์ด ํ˜ผํ•ฉ๋œ ์Šฌ๋Ÿฌ๋ฆฌ๋ฅผ ์ฃผ์ž…ํ•˜์—ฌ ์ง€๋ฐ˜๊ณผ ๊ต๋ฐ˜ํ•จ์œผ๋กœ์จ ๊ณ ํ™”๋œ ๊ฐœ๋Ÿ‰์ฒด๋ฅผ ์กฐ์„ฑํ•˜๋Š” ์ง€๋ฐ˜๊ฐœ๋Ÿ‰๊ณต๋ฒ•์ด๋‹ค. ๊นŠ์ด 30 m ์ด์ƒ ์‹œ๊ณต์ด ๊ฐ€๋Šฅํ•˜๋ฉฐ, ์›์ง€๋ฐ˜์˜ ์—ญํ•™์  ํŠน์„ฑ ๋˜๋Š” ๋ฌผ๋ฆฌ์  ํŠน์„ฑ์„ ๊ฐœ์„ ํ•˜์—ฌ ์ง€๋ฐ˜์˜ ์ง€์ง€๋ ฅ์„ ์ฆ๋Œ€์‹œํ‚ค๋Š” ๊ณต๋ฒ•์œผ๋กœ ๊ตญ๋‚ด ๋ฟ๋งŒ ์•„๋‹ˆ๋ผ ํ•ด์™ธ์—์„œ๋„ ๋งŽ์ด ์ ์šฉ๋˜๊ณ  ์žˆ๋Š” ๋Œ€ํ‘œ์ ์ธ ์—ฐ์•ฝ์ง€๋ฐ˜ ๊ฐœ๋Ÿ‰๊ณต๋ฒ• ์ค‘ ํ•˜๋‚˜์ด๋‹ค.

DCM์€ ์ƒ๋ถ€๊ตฌ์กฐ๋ฌผ์˜ ์šฉ๋„ ๋ฐ ์„ค๊ณ„ ํ•˜์ค‘ ๋“ฑ์— ๋”ฐ๋ผ ํ”ผ์••์ด ์ž‘์šฉํ•˜๋Š” ์ง€์ธต๊นŒ์ง€ ๊ฐœ๋Ÿ‰์„ ํ•ด์•ผ ํ•˜๋Š” ๊ฒฝ์šฐ๊ฐ€ ๋ฐœ์ƒํ•œ๋‹ค. ์ผ๋ฐ˜์ ์œผ๋กœ ํ”ผ์••์ด ์ž‘์šฉํ•˜๋Š” ์ง€์ธต์€ ์ ํ† ์ธต๊ณผ ๊ฐ™์ด ํˆฌ์ˆ˜๊ณ„์ˆ˜๊ฐ€ ์ž‘์œผ๋‚˜, ํ•˜๋ถ€ ํ”ผ์••๋Œ€์ˆ˜์ธต์€ ๋ชจ๋ž˜ ๋ฐ ์ž๊ฐˆ๋กœ ์ด๋ฃจ์–ด์ ธ ํˆฌ์ˆ˜๊ณ„์ˆ˜๊ฐ€ ํฌ๋‹ค. ์ด๋กœ ์ธํ•ด ๊ฐœ๋Ÿ‰์ฒด์˜ ํฌ์„ ๋ฐ ์œ ์‹ค์ด ๋ฐœ์ƒํ•˜์—ฌ ๊ฐœ๋Ÿ‰์ฒด์˜ ๊ฐ•๋„ ๋ฐœํ˜„ ํšจ๊ณผ๋ฅผ ๊ธฐ๋Œ€ํ•˜๊ธฐ ํž˜๋“  ๊ฒฝ์šฐ๊ฐ€ ์ข…์ข… ๋ฐœ์ƒํ•  ์ˆ˜ ์žˆ๋‹ค(Song et al., 1991). Lee et al.(2016)์€ ์ˆ˜์น˜ํ•ด์„์„ ํ†ตํ•ด ๋ถ€์‚ฐ ๋‚™๋™๊ฐ• ๋ธํƒ€ ์ง€์—ญ ํ”ผ์••๋Œ€์ˆ˜์ธต์˜ ์ˆ˜๋ฆฌ์ „๋„๋„๋ฅผ ๋ถ„์„ํ•˜์˜€์œผ๋ฉฐ, ๊ทธ ๊ฒฐ๊ณผ, ์‹คํŠธ์งˆ ๋ชจ๋ž˜ ๋“ฑ์ด ์กด์žฌํ•  ๊ฒฝ์šฐ ํฐ ์ˆ˜๋ฆฌ์ „๋„๋„๋ฅผ ๊ฐ€์ง„๋‹ค๋Š” ๊ฒƒ์„ ๋ถ„์„ํ•œ ๋ฐ” ์žˆ๋‹ค. ํ”ผ์••๋Œ€์ˆ˜์ธต์— ๊ฐœ๋Ÿ‰์ฒด๋ฅผ ์ฃผ์ž…ํ•  ๊ฒฝ์šฐ ์ง€ํ•˜์ˆ˜์˜ ์ˆ˜ํ‰ ํ๋ฆ„์œผ๋กœ ์ธํ•ด ์‹œ๋ฉ˜ํŠธ ๊ณ ํ™”์žฌ์˜ ์œ ์‹ค์ด ๋ฐœ์ƒํ•  ์ˆ˜ ์žˆ๋‹ค. ์ด์— ๋”ฐ๋ผ ๊ฐœ๋Ÿ‰์ฒด์˜ ๊ณ ํ™”๊ฐ€ ์ž˜ ์ด๋ฃจ์–ด์ง€์ง€ ์•Š๊ณ  ๋น„๊ท ์งˆํ•œ ๊ฐœ๋Ÿ‰์ด ๋ฐœ์ƒํ•  ์ˆ˜ ์žˆ๋‹ค. ํŠนํžˆ, ์ง€๋ฐ˜ ๊ฐœ๋Ÿ‰ ๋“ฑ์„ ์œ„ํ•ด ํ”ผ์••๋Œ€์ˆ˜์ธต๊นŒ์ง€ ์ฒœ๊ณตํ•  ๊ฒฝ์šฐ, ํ”ผ์••์˜ ํ•ด์ œ๋กœ ์ƒํ–ฅ ์นจํˆฌ๊ฐ€ ๋ฐœ์ƒํ•  ์ˆ˜ ์žˆ๋‹ค(Kim, 2010). ์ด์ฒ˜๋Ÿผ ํ”ผ์••์ด ์กด์žฌํ•˜๋Š” ์ง€๋ฐ˜์„ ๊ฐœ๋Ÿ‰ํ•˜๊ฒŒ ๋  ๊ฒฝ์šฐ, ๊ฐ•๋„ ์ €ํ•˜๊ฐ€ ๋ฐœ์ƒํ•  ์šฐ๋ ค๊ฐ€ ์žˆ์œผ๋ฏ€๋กœ ํ”ผ์••์ด ๊ฐœ๋Ÿ‰์ฒด์˜ ๊ฐ•๋„ ๋ฐœํ˜„์— ๋ฏธ์น˜๋Š” ์˜ํ–ฅ์— ๊ด€ํ•œ ์—ฐ๊ตฌ๊ฐ€ ํ•„์š”ํ•œ ์‹œ์ ์ด๋‹ค.

๋”ฐ๋ผ์„œ ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ๋‚™๋™๊ฐ• ํ•˜๊ตฌ์˜ ์‹œ๋ฃŒ๋ฅผ ์ฑ„์ทจํ•˜์—ฌ ๋‹ค์–‘ํ•œ ํฌ๊ธฐ์˜ ํ”ผ์••์ด DCM ๊ฐœ๋Ÿ‰์ฒด์˜ ์ง€๋ฐ˜๊ณตํ•™์  ํŠน์„ฑ์— ๋ฏธ์น˜๋Š” ์˜ํ–ฅ์„ ์‹ค๋‚ด์‹คํ—˜์„ ํ†ตํ•ด ์•Œ์•„๋ณด์•˜๋‹ค. ๋™์ˆ˜๊ฒฝ์‚ฌ๋ฅผ ์ด์šฉํ•˜์—ฌ ์ƒํ–ฅ ํ๋ฆ„์˜ ํฌ๊ธฐ ์กฐ์ ˆ์ด ๊ฐ€๋Šฅํ•œ ๊ณต์‹œ์ฒด์šฉ ์ˆ˜์กฐ๋ฅผ ์ œ์ž‘ํ•˜์—ฌ ํ”ผ์•• ํฌ๊ธฐ์— ๋”ฐ๋ฅธ ๊ฐœ๋Ÿ‰์ฒด์˜ ์ผ์ถ•์••์ถ•๊ฐ•๋„, ํ•จ์ˆ˜๋น„ ๋ฐ ๋‹จ์œ„์ค‘๋Ÿ‰ ๋ณ€ํ™” ํŠน์„ฑ์„ ์•Œ์•„๋ณด์•˜๋‹ค. ๋˜ํ•œ ํ”ผ์••์— ์˜ํ•ด ๋ฐœ์ƒํ•œ ์œ ์ถœ์ˆ˜์— ๋Œ€ํ•˜์—ฌ ํŽ˜๋†€ํ”„ํƒˆ๋ ˆ์ธ ๋ฐ˜์‘์„ ํ†ตํ•ด ์šฉํƒˆ ํ˜„์ƒ์„ ์•Œ์•„๋ณด์•˜์œผ๋ฉฐ, ์ฃผ์ž์ „์žํ˜„๋ฏธ๊ฒฝ(scanning electron microscope, SEM)์„ ์ด์šฉํ•˜์—ฌ ํ”ผ์••์˜ ์ž‘์šฉ ์œ ๋ฌด์— ๋”ฐ๋ฅธ ๊ฐœ๋Ÿ‰์ฒด์˜ ์ž…์ž๊ตฌ์กฐ ๋ฐ ๊ฒฐํ•ฉ์ƒํƒœ๋ฅผ ํ™•์ธํ•˜์˜€๋‹ค. ๋ณธ ์—ฐ๊ตฌ ๊ฒฐ๊ณผ๋ฅผ ํ†ตํ•ด ํ”ผ์••๋Œ€์ˆ˜์ธต์ด ์กด์žฌํ•˜๋Š” ๋ชจ๋ž˜ ๋ฐ ์ ํ†  ์ง€๋ฐ˜์„ ๊ฐœ๋Ÿ‰ํ•จ์— ์žˆ์–ด, ํ”ผ์••์˜ ์ž‘์šฉ์ด ์ง€๋ฐ˜ ๊ฐœ๋Ÿ‰์— ๋ฏธ์น˜๋Š” ์˜ํ–ฅ์„ ์˜ˆ์ธกํ•˜๊ธฐ ์œ„ํ•œ ๊ธฐ์ดˆ์ž๋ฃŒ๋ฅผ ์ œ๊ณตํ•  ์ˆ˜ ์žˆ์„ ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

2. ์‹คํ—˜ ์กฐ๊ฑด ๋ฐ ๋ฐฉ๋ฒ•

2.1 ์‹คํ—˜ ์กฐ๊ฑด

๋‚™๋™๊ฐ• ํ•˜๊ตฌ ์ง€์ธต ๊ตฌ์กฐ๋Š” Fig. 1์— ๋‚˜ํƒ€๋‚œ ๋ฐ”์™€ ๊ฐ™์ด ์ผ๋ฐ˜์ ์œผ๋กœ ๋ถ€์ง€ ์กฐ์„ฑ์„ ์œ„ํ•œ ๋งค๋ฆฝํ† ์ธต, ์ƒ๋ถ€ ๋ชจ๋ž˜์ธต, ์ค‘๊ฐ„ ์ ํ† ์ธต, ํ•˜๋ถ€ ๋ชจ๋ž˜ยท์ž๊ฐˆ์ธต ๋ฐ ๊ธฐ๋ฐ˜์•”์˜ ์ง€์ธต ๊ตฌ์กฐ๋กœ ๋˜์–ด์žˆ๋‹ค. ์—ฌ๊ธฐ์„œ ์ค‘๊ฐ„ ์ ํ† ์ธต์€ ๋ถˆํˆฌ์ˆ˜์ธต์œผ๋กœ ์ž‘์šฉํ•˜๋ฉฐ, ํ•˜๋ถ€ ๋ชจ๋ž˜ยท์ž๊ฐˆ์ธต์€ ํˆฌ์ˆ˜๊ณ„์ˆ˜๊ฐ€ ์ปค์„œ ๋™์ˆ˜๊ฒฝ์‚ฌ์— ๋”ฐ๋ฅธ ํ๋ฆ„์ด ๋ฐœ์ƒํ•˜๋Š” ์ง€์ธต์ด๋‹ค. ํ•˜๋ถ€ ๋ชจ๋ž˜์ธต์€ ๋ถˆํˆฌ์ˆ˜์ธต์ธ ์ ํ† ์ธต ์•„๋ž˜์— ์žˆ์–ด ์ง€ํ˜•์  ํŠน์„ฑ ๋˜๋Š” ์ง€ํ•˜์ˆ˜์œ„์˜ ์กฐ๊ฑด ๋“ฑ์— ๋”ฐ๋ผ ํ”ผ์••์ด ์ž‘์šฉํ•  ์ˆ˜ ์žˆ๋‹ค. ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ํ”ผ์••์˜ ์ž‘์šฉ์— ๋”ฐ๋ฅธ ์ง€๋ฐ˜๊ฐœ๋Ÿ‰์ฒด์˜ ์—ญํ•™์  ํŠน์„ฑ์„ ์•Œ์•„๋ณด๊ธฐ ์œ„ํ•ด ๋‚™๋™๊ฐ• ํ•˜๊ตฌ์— ์œ„์น˜ํ•œ ํ•˜๋ถ€ ๋ชจ๋ž˜์ธต๊ณผ ์ค‘๊ฐ„ ์ ํ† ์ธต ์‹œ๋ฃŒ๋ฅผ ์ฑ„์ทจํ•˜์—ฌ ์‹ค๋‚ด์‹คํ—˜์— ์‚ฌ์šฉํ•˜์˜€๋‹ค.

์‹œ๋ฃŒ์˜ ๊ท ์งˆ์„ฑ์„ ์œ„ํ•ด ์ฑ„์ทจ๋œ ์‹œ๋ฃŒ๋Š” ํ•œ๋ฒˆ์— ๊ต๋ฐ˜ํ•˜์˜€์œผ๋ฉฐ, ์‹œ๋ฃŒ๋ฅผ ๊ต๋ฐ˜ํ•˜๊ธฐ ์ „์— 4๋ฒˆ์ฒด(4.75 mm)๋กœ ์ฒด๊ฐ€๋ฆ„์„ ํ•˜์—ฌ ์ž๊ฐˆ, ์กฐ๊ฐœ ๋“ฑ๊ณผ ๊ฐ™์€ ๋ถˆ์ˆœ๋ฌผ์„ ์ œ๊ฑฐํ•˜์˜€๋‹ค. Table 1์€ ๋ณธ ์—ฐ๊ตฌ์—์„œ ์‚ฌ์šฉ๋œ ๋ชจ๋ž˜ ๋ฐ ์ ํ† ์˜ ๊ธฐ๋ณธ๋ฌผ์„ฑ์„ ๋‚˜ํƒ€๋‚ธ๋‹ค. ๋ชจ๋ž˜์˜ ์ดˆ๊ธฐ ํ•จ์ˆ˜๋น„๋Š” 25.8 %, ๋น„์ค‘์€ 2.67์ด๋ฉฐ, ํ†ต์ผ๋ถ„๋ฅ˜๋ฒ•(USCS)์— ์˜ํ•œ ๋ถ„๋ฅ˜ ๊ฒฐ๊ณผ ์‹คํŠธ์งˆ๋ชจ๋ž˜(SM)์œผ๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค. ์ ํ† ์˜ ๊ฒฝ์šฐ ์ดˆ๊ธฐ ํ•จ์ˆ˜๋น„ 29.7 %, ์•ก์„ฑํ•œ๊ณ„ 38.2 %์ด๋ฉฐ, USCS ๋ถ„๋ฅ˜ ๊ฒฐ๊ณผ ์••์ถ•์„ฑ์ด ๋‚ฎ์€ ์ ํ† (CL)๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค.

Table 1. Geotechnical Properties of Soils

Type

Initial water content (%)

Specific gravity

Atterberg limit (%)

USCS

LL

PI

Sand

25.8

2.67

NP

NP

SM

Clay

29.7

2.68

38.2

16.8

CL

Fig. 1. Soil Profile at Nakdong River Estuary
../../Resources/KSCE/Ksce.2022.42.2.0187/fig1.png

2.2 ์‹คํ—˜ ๋ฐฉ๋ฒ•

ํ”ผ์•• ํฌ๊ธฐ์— ๋”ฐ๋ฅธ DCM ๊ฐœ๋Ÿ‰์ฒด์˜ ์—ญํ•™์  ํŠน์„ฑ์„ ์•Œ์•„๋ณด๊ธฐ ์œ„ํ•ด ํ”ผ์•• ์ž‘์šฉ๊ณผ ํฌ๊ธฐ ์ œ์–ด๊ฐ€ ๊ฐ€๋Šฅํ•œ ์ผ์ถ•์••์ถ•๊ฐ•๋„ ๊ณต์‹œ์ฒด์šฉ ํ”ผ์•• ์ˆ˜์กฐ ์‹คํ—˜ ์žฅ๋น„(Fig. 2(a))๋ฅผ ์ œ์ž‘ํ•˜์˜€๋‹ค. ๊ณต์‹œ์ฒด์šฉ ํ”ผ์•• ์ˆ˜์กฐ๋Š” ๋†’์ด 17 cm, ํญ 66 cm, ๋„ˆ๋น„ 32 cm์˜ ์ง์œก๋ฉด์ฒด ํ˜•ํƒœ๋กœ ์•„ํฌ๋ฆด์„ ์ด์šฉํ•˜์—ฌ ์ œ์ž‘ํ•˜์˜€๋‹ค. ๊ณต์‹œ์ฒด์šฉ ํ”ผ์•• ์ˆ˜์กฐ๋Š” ์ƒ๋ถ€ ์ˆ˜์กฐ์™€ ํŠœ๋ธŒ๋กœ ์—ฐ๊ฒฐ๋˜์–ด ์žˆ์œผ๋ฉฐ, ์ƒ๋ถ€ ์ˆ˜์กฐ์˜ ๋†’์ด๋ฅผ ์ด์šฉํ•˜์—ฌ ํ”ผ์••์˜ ํฌ๊ธฐ๋ฅผ ์กฐ์ ˆํ•  ์ˆ˜ ์žˆ๋‹ค.

์‹คํ—˜ ๋ฐฉ๋ฒ•์€ ๋‹ค์Œ๊ณผ ๊ฐ™๋‹ค. ๋จผ์ € ๋ชจ๋ž˜ ๋ฐ ์ ํ†  ๊ฐœ๋Ÿ‰์ฒด๋ฅผ ๊ฐ ๋ฐฐํ•ฉ๋น„๋ณ„๋กœ ๊ต๋ฐ˜ํ•˜์—ฌ PVC ๋ชฐ๋“œ์— ์„ฑํ˜•ํ•œ ๋’ค ํ”ผ์•• ์ˆ˜์กฐ์— ์—ฐ๊ฒฐํ•œ๋‹ค. ์ดํ›„ ํ”ผ์•• ์ œ์–ด์šฉ ๋ฒจ๋ธŒ๋ฅผ ์—ด์–ด ํ”ผ์••์ด ๊ณต์‹œ์ฒด์— ์ž‘์šฉํ•˜๋„๋ก ํ•˜์˜€๋‹ค. ์—ฌ๊ธฐ์„œ, ๊ณต์‹œ์ฒด์šฉ ํ”ผ์•• ์ˆ˜์กฐ๋Š” ๊ณต์‹œ์ฒด๊ฐ€ ์„ค์น˜๋˜๋Š” ๋ฐ”๋‹ฅ ๋ถ€๋ถ„์— ๊ณต์‹œ์ฒด์˜ ๋ฉด์ ๋งŒํผ ๋šซ๋ ค ์žˆ์–ด ๋ฌผ์˜ ํ๋ฆ„์ด ๊ฐ€๋Šฅํ•˜๋ฉฐ, ๊ทธ๋ฌผ๋ง(mesh gird)๊ณผ ์—ฌ๊ณผ์ง€(filter paper)๋ฅผ ์„ค์น˜ํ•˜์—ฌ ์‹œ๋ฃŒ์˜ ํฌ์„ค์ด ๊ฐ€๋Šฅํ•˜๋ฉด์„œ ํ”ผ์••์ด ์‹œ๋ฃŒ์˜ ๋ฐ”๋‹ฅ ๋ถ€๋ถ„ ์ „์ฒด์— ์ž‘์šฉํ•  ์ˆ˜ ์žˆ๋„๋ก ํ•˜์˜€๋‹ค(Fig. 2(a)).

์ผ์ถ•์••์ถ•๊ฐ•๋„์‹œํ—˜(KS F2314)์„ ์œ„ํ•œ ๊ฐœ๋Ÿ‰๊ณต์‹œ์ฒด์˜ ํฌ๊ธฐ๋Š” ์ง๊ฒฝ 5 cm, ๋†’์ด 10 cm์ด๋ฉฐ, ํ”ผ์••์„ ๋ฐ›๋Š” ์ƒํƒœ๋กœ 7์ผ๊ฐ„ ์ˆ˜์ค‘์–‘์ƒํ•œ ํ›„ ์‹œํ—˜์„ ์ˆ˜ํ–‰ํ•˜์˜€๋‹ค. ์‹œํ—˜์€ ๊ณต์‹œ์ฒด์˜ ํŒŒ๊ดด ํ›„(์ตœ๋Œ€๊ฐ•๋„ ์ดํ›„) ์ข…๋ฃŒํ•˜์˜€์œผ๋ฉฐ, ํ•˜์ค‘์˜ ์ œ์–ด ์†๋„๋Š” 1 mm/min์œผ๋กœ ํ•˜์˜€๋‹ค. ๊ณต์‹œ์ฒด๋Š” ์ด 3๊ฐœ์”ฉ ์ œ์ž‘ํ•˜์—ฌ ์‹คํ—˜์  ์˜ค์ฐจ๋ฅผ ์ €๊ฐํ•˜๊ณ ์ž ํ•˜์˜€๋‹ค. ๋˜ํ•œ ํ”ผ์•• ํฌ๊ธฐ์— ๋”ฐ๋ฅธ ๊ฐ๊ฐ ๊ฐœ๋Ÿ‰์ฒด์˜ ๋ฌด๊ฒŒ๋ฅผ ์ธก์ •ํ•˜์—ฌ ๋‹จ์œ„์ค‘๋Ÿ‰์„ ๊ณ„์‚ฐํ•˜์˜€์œผ๋ฉฐ, ํ•จ์ˆ˜๋น„(KS F 2306)์˜ ๋ณ€ํ™”๋ฅผ ์•Œ์•„๋ณด๊ธฐ ์œ„ํ•ด ์‹คํ—˜ ์ข…๋ฃŒ ํ›„ ์‹œ๋ฃŒ๋ฅผ ์ฑ„์ทจํ•˜์—ฌ ํ•จ์ˆ˜๋น„์˜ ๋ณ€ํ™”๋ฅผ ์ธก์ •ํ•˜์˜€๋‹ค.

ํ”ผ์••์˜ ํฌ๊ธฐ๋Š” ๋™์ˆ˜๊ฒฝ์‚ฌ(hydrauric gradient, i=โ–ณH/L)๋ฅผ ๋ฐ”ํƒ•์œผ๋กœ ๋‘ ์ง€์ ๊ฐ„์˜ ์ˆ˜์œ„์ฐจ๋ฅผ ์ด์šฉํ•˜์—ฌ ์กฐ์ ˆํ•˜์˜€๋‹ค. ์‹คํ—˜์— ์ ์šฉํ•œ ํ”ผ์••์˜ ํฌ๊ธฐ๋Š” Table 2์— ๋‚˜ํƒ€๋‚œ ๋ฐ”์™€ ๊ฐ™์ด 0.1, 0.3, 0.5 ๋ฐ 5.0์œผ๋กœ ํ•˜์˜€๋‹ค. ๋˜ํ•œ ๋น„๊ต๊ตฐ์ธ ๋น„ํ”ผ์•• ์กฐ๊ฑด(i = 0.0)์˜ ๊ณต์‹œ์ฒด๋ฅผ ์ œ์ž‘ํ•˜์—ฌ ์—ญํ•™์  ํŠน์„ฑ์„ ๋น„๊ตํ•˜์˜€๋‹ค. ๋ชจ๋ž˜ ๋ฐ ์ ํ†  ์ง€๋ฐ˜์˜ ์ดˆ๊ธฐ ๋‹จ์œ„์ค‘๋Ÿ‰์€ ๊ฐ๊ฐ 18.0 kN/ใŽฅ๊ณผ 17.0 kN/ใŽฅ์ด๋‹ค. ์‹œํ—˜์šฉ ์‹œ๋ฃŒ์˜ ๋ฐฐํ•ฉ์€ DCM ๊ฐœ๋Ÿ‰ ์กฐ๊ฑด์„ ๊ณ ๋ คํ•˜์—ฌ ๋ฌผ/์‹œ๋ฉ˜ํŠธ ๋น„์œจ์„ 1.57:1๋กœ ํ•˜์—ฌ DCM ๊ณต์‹œ์ฒด๋ฅผ ์ œ์ž‘ํ•˜์˜€๋‹ค.

Fig. 2. DCM Specimen Under Various Artesian Pressures
../../Resources/KSCE/Ksce.2022.42.2.0187/fig2.png
Table 2. Experiment Conditions of Soil Mixtures

Soil type

Hydraulic gradient, i

Unit weight

(kN/ใŽฅ)

Water/ cement ratio

Mixing weight (kg/ใŽฅ)

Cement

Water

Sand

0.0, 0.1, 0.3, 0.5, 5.0

18.0

1.57 : 1

254

398.8

Clay

0.0, 0.1, 0.3, 0.5, 5.0

17.0

3. ์‹คํ—˜ ๊ฒฐ๊ณผ ๋ฐ ๋ถ„์„

3.1 ๊ฐœ๋Ÿ‰์ฒด์˜ ์—ญํ•™์  ํŠน์„ฑ

Fig. 3์€ ํ”ผ์•• ํฌ๊ธฐ์— ๋”ฐ๋ฅธ ๊ณต์‹œ์ฒด์˜ ํŒŒ๊ดด ํ˜•์ƒ์„ ๋‚˜ํƒ€๋‚ธ๋‹ค. Fig. 3(a)์— ๋‚˜ํƒ€๋‚œ ๋ฐ”์™€ ๊ฐ™์ด ํ”ผ์••์ด ์ž‘์šฉํ•˜์ง€ ์•Š์€ ๊ณต์‹œ์ฒด์˜ ๊ฒฝ์šฐ ํŒŒ๊ดด ๊ท ์—ด์ด ์ฃผ๋กœ ๊ณต์‹œ์ฒด์˜ ์ค‘์•™์—์„œ ๋ฐœ์ƒํ•˜๋Š” ์ผ๋ฐ˜์ ์ธ ์ „๋‹จํŒŒ๊ดด ๊ฑฐ๋™์„ ๋ณด์ด๋Š” ๊ฒƒ์œผ๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค. ๋ฐ˜๋ฉด ํ”ผ์••(i = 0.5)์ด ์ž‘์šฉํ•˜๋Š” ๊ณต์‹œ์ฒด์˜ ๊ฒฝ์šฐ(Fig. 3(b)) ๊ณต์‹œ์ฒด์˜ ํ•˜๋‹จ๋ถ€์—์„œ ํŒŒ๊ดด๊ฐ€ ์ฃผ๋กœ ๋ฐœ์ƒํ•˜๋Š” ๊ฒฝํ–ฅ์„ ๋ณด์˜€๋‹ค. ์ด๋Ÿฌํ•œ ๊ฒฐ๊ณผ๋Š” ํ”ผ์•• ์ž‘์šฉ์œผ๋กœ ์ธํ•ด ๊ณต์‹œ์ฒด ํ•˜๋‹จ๋ถ€์— ๋ฌผ์ด ์นจํˆฌํ•˜์—ฌ ์‹œ๋ฉ˜ํŠธ์˜ ๊ณ ํ™”์ž‘์šฉ์— ์˜ํ–ฅ์„ ๋ฏธ์ณ ๋‚˜ํƒ€๋‚œ ๊ฒฐ๊ณผ๋กœ ํŒ๋‹จ๋œ๋‹ค. ์ฆ‰, ๋น„ํ”ผ์•• ์ƒํƒœ์˜ ๊ณต์‹œ์ฒด๋Š” ๊ณ ํ™”๊ฐ€ ์ „์ฒด์ ์œผ๋กœ ๊ท ๋“ฑํ•˜๊ฒŒ ์ด๋ฃจ์–ด์ง€๋ฏ€๋กœ ์ƒ์žฌํ•˜์ค‘์— ๋Œ€ํ•œ ์ €ํ•ญ์ด ์ž˜ ์ด๋ฃจ์–ด์ง€๋Š” ๋ฐ˜๋ฉด, ํ”ผ์••์ด ์ž‘์šฉํ•˜๋Š” ๊ณต์‹œ์ฒด์˜ ๊ฒฝ์šฐ ๊ณต์‹œ์ฒด ํ•˜๋‹จ๋ถ€๊ฐ€ ์ƒ๋Œ€์ ์œผ๋กœ ์ทจ์•ฝํ•ด์ ธ ๊ฐ•๋„ ์ €ํ•˜๊ฐ€ ๋ฐœ์ƒํ•  ์ˆ˜ ์žˆ๋Š” ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

Fig. 3. Failure Behavior of Specimens
../../Resources/KSCE/Ksce.2022.42.2.0187/fig3.png

Figs. 4 and 5๋Š” ๊ฐ๊ฐ ํ”ผ์•• ํฌ๊ธฐ์— ๋”ฐ๋ฅธ ๋ชจ๋ž˜ ๋ฐ ์ ํ†  ๊ฐœ๋Ÿ‰์ฒด์˜ ์ผ์ถ•์••์ถ•๊ฐ•๋„ ์‹œํ—˜ ๊ฒฐ๊ณผ๋ฅผ ๋‚˜ํƒ€๋‚ธ๋‹ค. ์‹œํ—˜์€ ๋™์ผํ•œ ๋ฐฐํ•ฉ๋น„๋กœ ์ œ์ž‘๋œ ๊ณต์‹œ์ฒด์— ํ”ผ์•• ํฌ๊ธฐ๋ฅผ ์„œ๋กœ ๋‹ค๋ฅด๊ฒŒ ํ•˜์—ฌ(i = 0.0, 0.1, 0.3, 0.5) 7์ผ๊ฐ„ ์–‘์ƒํ•˜์˜€๋‹ค. ๊ฐ ํ”ผ์•• ์กฐ๊ฑด์—์„œ ์–‘์ƒ๋œ ์‹œ๋ฃŒ๋Š” 3๊ฐœ์ด๋‹ค. ์–‘์ƒ๋œ ๊ณต์‹œ์ฒด์— ๋Œ€ํ•˜์—ฌ ๋™์ผํ•œ ๋ฐฉ๋ฒ•์œผ๋กœ ์ผ์ถ•์••์ถ•๊ฐ•๋„ ์‹œํ—˜์„ ํ•˜์˜€๋‹ค.

๊ฐ๊ฐ ์ง€๋ฐ˜ ๋ฐ ํ”ผ์•• ์กฐ๊ฑด์— ๋”ฐ๋ฅธ ์‹คํ—˜ ๊ฒฐ๊ณผ ์ผ๋ถ€ ๊ณต์‹œ์ฒด์˜ ๊ฒฝ์šฐ์—๋Š” ํŒŒ๊ดด ์ดํ›„ ๊ฑฐ๋™ ์ฐจ์ด๊ฐ€ ์•ฝ๊ฐ„ ์žˆ์œผ๋‚˜, ์ „๋ฐ˜์ ์œผ๋กœ ์‘๋ ฅ-๋ณ€ํ˜• ํŠน์„ฑ์ด ์œ ์‚ฌํ•œ ๊ฑฐ๋™์„ ๋ณด์˜€๋‹ค. ๋ชจ๋ž˜ ๊ฐœ๋Ÿ‰์ฒด์˜ ๊ฒฝ์šฐ(Fig. 4) ํ•ญ๋ณต์‘๋ ฅ์€ ์•ฝ 722 kPaโˆผ415 kPa์˜ ๋ฒ”์œ„๋กœ ๋‚˜ํƒ€๋‚ฌ์œผ๋ฉฐ, ํŒŒ๊ดด์‹œ ์ถ•๋ณ€ํ˜•๋ฅ ์€ ์•ฝ 1.2~2.0 %์˜ ๋ฒ”์œ„๋ฅผ ๋ณด์˜€๋‹ค. ์ ํ†  ๊ฐœ๋Ÿ‰์ฒด์˜ ๊ฒฝ์šฐ(Fig. 5) ํ”ผ์••์˜ ํฌ๊ธฐ์— ๋”ฐ๋ผ ํ•ญ๋ณต์‘๋ ฅ์€ ์•ฝ 294 kPaโˆผ172 kPa์˜ ๋ฒ”์œ„๋กœ ์ ์ฐจ ๊ฐ์†Œํ•˜๋Š” ๊ฒƒ์œผ๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค.

Fig. 6์€ ๊ฐ ์ง€๋ฐ˜ ์กฐ๊ฑด์—์„œ ํ”ผ์••์˜ ํฌ๊ธฐ ๋ณ€ํ™”์— ๋”ฐ๋ฅธ ์‘๋ ฅ-๋ณ€ํ˜• ๊ฑฐ๋™์„ ๋‚˜ํƒ€๋‚ธ๋‹ค. ํ”ผ์••์ด ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ์ตœ๋Œ€ ์ฒจ๋‘์‘๋ ฅ์˜ ํฌ๊ธฐ๊ฐ€ ๊ฐ์†Œํ•˜๋ฉฐ, ํŒŒ๊ดด์‹œ ์ถ•๋ณ€ํ˜•๋ฅ ์€ ์ ์ฐจ ์ฆ๊ฐ€ํ•˜๋Š” ๊ฒฝํ–ฅ์„ ๋ณด์˜€๋‹ค. ๋˜ํ•œ ์‘๋ ฅ-๋ณ€ํ˜• ๊ฑฐ๋™ ํ˜•ํƒœ๋Š” ํ”ผ์••์ด ์ž‘์šฉํ•˜์ง€ ์•Š๋Š” ๊ฐœ๋Ÿ‰์ฒด์˜ ๊ฒฝ์šฐ ๋šœ๋ ทํ•œ ์ทจ์„ฑ์ ์ธ ๊ฑฐ๋™(brittle behavior) ํ˜•ํƒœ๋ฅผ ๋ณด์˜€์œผ๋‚˜, ํ”ผ์••์ด ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ํŒŒ๊ดด์‹œ ์ถ•๋ณ€ํ˜•๋ฅ ์ด ์ ์ฐจ ์ฆ๊ฐ€ํ•˜๋Š” ์—ฐ์„ฑ์ ์ธ ๊ฑฐ๋™(ductile behavior) ํŠน์„ฑ์„ ๋ณด์˜€๋‹ค.

Fig. 4. Unconfined Compressive Test Results of Sand Mixture
../../Resources/KSCE/Ksce.2022.42.2.0187/fig4.png
Fig. 5. Unconfined Compressive Test Results of Clay Mixtures
../../Resources/KSCE/Ksce.2022.42.2.0187/fig5.png
Fig. 6. Stress-Strain Behavior Under Different Hydraulic Gradients
../../Resources/KSCE/Ksce.2022.42.2.0187/fig6.png

Fig. 7์€ ํ”ผ์•• ํฌ๊ธฐ์— ๋”ฐ๋ฅธ ๊ฐ๊ฐ ๋ชจ๋ž˜ ๋ฐ ์ ํ†  ๊ฐœ๋Ÿ‰์ฒด์˜ ํ• ์„ ํƒ„์„ฑ๊ณ„์ˆ˜(E50)์™€ ์ผ์ถ•์••์ถ•๊ฐ•๋„(qu)์˜ ๊ด€๊ณ„๋ฅผ ๋‚˜ํƒ€๋‚ธ๋‹ค. ์—ฌ๊ธฐ์„œ, ํ• ์„ ํƒ„์„ฑ๊ณ„์ˆ˜๋Š” ๊ฐœ๋Ÿ‰์ฒด ์••์ถ•๊ฐ•๋„์˜ 0.5๋ฐฐ์— ํ•ด๋‹นํ•˜๋Š” ์••์ถ•์‘๋ ฅ์ ์˜ ์ ‘์„  ๊ธฐ์šธ๊ธฐ๋กœ ๊ณ„์‚ฐํ•˜์˜€๋‹ค. ๋ชจ๋ž˜ ๋ฐ ์ ํ†  ๊ฐœ๋Ÿ‰์ฒด์˜ ํ• ์„ ํƒ„์„ฑ๊ณ„์ˆ˜๋Š” ๊ฐ๊ฐ ์ผ์ถ•์••์ถ•๊ฐ•๋„์˜ ์•ฝ 100~146๋ฐฐ ๋ฐ ์•ฝ 90~123๋ฐฐ ์ •๋„์˜ ๋ฒ”์œ„๋ฅผ ๊ฐ–๋Š” ๊ฒƒ์œผ๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค. ๋˜ํ•œ ํ”ผ์••์˜ ํฌ๊ธฐ๊ฐ€ ์ฆ๊ฐ€ํ• ์ˆ˜๋ก ํ• ์„ ํƒ„์„ฑ๊ณ„์ˆ˜์™€ ์ผ์ถ•์••์ถ•๊ฐ•๋„ ๊ด€๊ณ„ ๊ทธ๋ž˜ํ”„์˜ ๊ธฐ์šธ๊ธฐ๊ฐ€ ์ ์ฐจ ๊ฐ์†Œํ•˜๋Š” ๊ฒฝํ–ฅ์„ ๋ณด์˜€๋‹ค. ์ด๋Š” ํ”ผ์••์ด ์ž‘์šฉํ•จ์— ๋”ฐ๋ผ ๊ฐœ๋Ÿ‰์ฒด์˜ ๊ฐ•๋„์™€ ํƒ„์„ฑ๊ณ„์ˆ˜๋Š” ํ•จ๊ป˜ ์ž‘์•„์ง€๋‚˜, ์—ฐ์„ฑ๊ฑฐ๋™์œผ๋กœ ํƒ„์„ฑ๊ณ„์ˆ˜๊ฐ€ ๋” ํฌ๊ฒŒ ๊ฐ์†Œํ•œ๋‹ค๋Š” ๊ฒƒ์„ ์˜๋ฏธํ•œ๋‹ค.

Fig. 8์€ ํ”ผ์••์˜ ํฌ๊ธฐ์— ๋”ฐ๋ฅธ ๋ชจ๋ž˜ ๋ฐ ์ ํ†  ๊ฐœ๋Ÿ‰์ฒด์˜ ์ผ์ถ•์••์ถ•๊ฐ•๋„, ๋‹จ์œ„์ค‘๋Ÿ‰ ๋ฐ ํ•จ์ˆ˜๋น„์˜ ๋ถ„ํฌ๋ฅผ ๋‚˜ํƒ€๋‚ธ๋‹ค. ๋น„ํ”ผ์•• ์กฐ๊ฑด์„ ๊ธฐ์ค€์œผ๋กœ ๊ฐ ํ”ผ์•• ํฌ๊ธฐ์— ๋”ฐ๋ฅธ ๋ณ€ํ™”๋Ÿ‰์„ ์‚ดํŽด๋ณด๋ฉด ์ผ์ถ•์••์ถ•๊ฐ•๋„์™€ ๋‹จ์œ„์ค‘๋Ÿ‰์€ ํ”ผ์••์˜ ํฌ๊ธฐ๊ฐ€ ์ฆ๊ฐ€ํ• ์ˆ˜๋ก ์„ ํ˜•์ ์œผ๋กœ ๊ฐ์†Œํ•˜์˜€์œผ๋ฉฐ, ํ•จ์ˆ˜๋น„์˜ ๊ฒฝ์šฐ ์ ์ฐจ ์ฆ๊ฐ€ํ•˜๋Š” ๊ฒฝํ–ฅ์„ ๋ณด์˜€๋‹ค.

Fig. 8(a)์— ๋‚˜ํƒ€๋‚œ ๋ฐ”์™€ ๊ฐ™์ด ์ผ์ถ•์••์ถ•๊ฐ•๋„์˜ ๊ฒฝ์šฐ ๋ชจ๋ž˜ ์ง€๋ฐ˜์—์„œ ํ”ผ์••์˜ ํฌ๊ธฐ๊ฐ€ ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ์•ฝ 10.2โˆผ42.4 %, ์ ํ†  ์ง€๋ฐ˜์—์„œ ์•ฝ 7.5โˆผ36.2 %์˜ ๋ฒ”์œ„๋กœ ๊ฐ์†Œํ•˜๋Š” ๊ฒฐ๊ณผ๋ฅผ ๋ณด์˜€์œผ๋ฉฐ, ๋‹จ์œ„์ค‘๋Ÿ‰์€(Fig. 8(b)) ๊ฐ๊ฐ ์•ฝ 9.1 %์™€ 11.6 % ๊ฐ€๋Ÿ‰ ๊ฐ์†Œํ•˜์˜€๋‹ค. ๋˜ํ•œ Fig. 8(c)์—์„œ ๋ณด๋Š” ๋ฐ”์™€ ๊ฐ™์ด ๋ชจ๋ž˜ ๋ฐ ์ ํ†  ๊ฐœ๋Ÿ‰์ฒด์˜ ํ•จ์ˆ˜๋น„๋Š” ํ”ผ์••์ด ์ปค์งˆ์ˆ˜๋ก ๊ฐ๊ฐ ์•ฝ 15.9 % ๋ฐ 21.8 % ๊ฐ€๋Ÿ‰ ์ฆ๊ฐ€ํ•˜๋Š” ๊ฒฐ๊ณผ๋ฅผ ๋ณด์˜€๋‹ค. ํŠนํžˆ ๋™์ˆ˜๊ฒฝ์‚ฌ๊ฐ€ 0.1, 0.3๊ณผ ๊ฐ™์ด ๋‚ฎ์€ ํ”ผ์•• ์กฐ๊ฑด์—์„œ๋ณด๋‹ค ๋†’์€ ํ”ผ์••(i = 0.5)์—์„œ ๊ฐ ๋ณ€ํ™”๋Ÿ‰์˜ ๊ธฐ์šธ๊ธฐ๊ฐ€ ๋” ํฌ๊ฒŒ ๋‚˜ํƒ€๋‚˜๋Š” ๊ฒฝํ–ฅ์„ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. ์ด๋Ÿฌํ•œ ๊ฒฐ๊ณผ๋Š” ํ”ผ์••์˜ ํฌ๊ธฐ๊ฐ€ ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ๊ณต์‹œ์ฒด์˜ ํ•˜๋‹จ์—์„œ๋ถ€ํ„ฐ ๋ฌผ์˜ ์ƒํ–ฅ ์นจํˆฌ๊ฐ€ ํฌ๊ฒŒ ๋ฐœ์ƒํ•˜์—ฌ ์‹œ๋ฉ˜ํŠธ์˜ ์ˆ˜ํ™”๋ฐ˜์‘์ด ์ƒ๋Œ€์ ์œผ๋กœ ์ €ํ•˜๋œ๋‹ค. ์ด๋กœ ์ธํ•ด ํ”ผ์••์ด ์••์ถ•๊ฐ•๋„ ๊ฐ์†Œ, ๋‹จ์œ„์ค‘๋Ÿ‰ ๊ฐ์†Œ ๋ฐ ํ•จ์ˆ˜๋น„ ์ฆ๊ฐ€ ํ˜„์ƒ์œผ๋กœ ์˜ํ–ฅ์„ ๋ฏธ์นœ ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

ํ”ผ์••์— ์˜ํ•œ ๊ฐœ๋Ÿ‰์ฒด์˜ ์šฉํƒˆ ํ˜„์ƒ์„ ํ™•์ธํ•˜๊ธฐ ์œ„ํ•ด Fig. 9์™€ ๊ฐ™์ด ํŽ˜๋†€ํ”„ํƒˆ๋ ˆ์ธ ์šฉ์•ก์„ ์ด์šฉํ•˜์—ฌ ๋ฐ˜์‘์„ ํ™•์ธํ•˜์˜€๋‹ค. ์ด๋•Œ ์‹œ๋ฃŒ๋Š” ๋™์ˆ˜๊ฒฝ์‚ฌ 0.5์ธ ๋ชจ๋ž˜ ๊ฐœ๋Ÿ‰์ฒด๋ฅผ ์ด์šฉํ•˜์˜€๋‹ค. ํŽ˜๋†€ํ”„ํƒˆ๋ ˆ์ธ(C20H14O4) ์šฉ์•ก์€ ์ผ๋ฐ˜์ ์œผ๋กœ ์•Œ์นผ๋ฆฌ์„ฑ์ธ ์ฝ˜ํฌ๋ฆฌํŠธ์˜ ํƒ„์‚ฐํ™” ํ˜„์ƒ์„ ์ธก์ •ํ•˜๊ธฐ ์œ„ํ•œ ๋ฐฉ๋ฒ•์œผ๋กœ ์‚ฌ์šฉ๋œ๋‹ค(Chun et al., 2008; Kim et al., 2008b). ์‹œ๋ฉ˜ํŠธ๊ฐ€ ํ˜ผํ•ฉ๋œ ๊ฐœ๋Ÿ‰์ฒด์˜ ์—ผ๊ธฐ ๋†๋„๋Š” ์‹œ๋ฉ˜ํŠธ ์ˆ˜ํ™”๋ฌผ ์ค‘ 20 % ์ด์ƒ์„ ์ฐจ์ง€ํ•˜๋Š” Ca(OH)2์— ๊ธฐ์ธํ•œ๋‹ค. ํŽ˜๋†€ํ”„ํƒˆ๋ ˆ์ธ ์šฉ์•ก์€ ์—ผ๊ธฐ์„ฑ์—์„œ ๋ถ‰์€์ƒ‰์œผ๋กœ ๋ฐ˜์‘ํ•˜๋ฏ€๋กœ ์ด๋ฅผ ํ†ตํ•ด ๊ณ ํ™”์žฌ์˜ ์œ ์‹ค ์ •๋„๋ฅผ ์•Œ ์ˆ˜ ์žˆ๋‹ค.

์œ ์ž…์ˆ˜(inflow water)์˜ ๊ฒฝ์šฐ ํŽ˜๋†€ํ”„ํƒˆ๋ ˆ์ธ ์šฉ์•ก์— ๋Œ€ํ•œ ๋ฐ˜์‘์ด ๋‚˜ํƒ€๋‚˜์ง€ ์•Š์•˜์œผ๋‚˜, ์— ์˜ํ•ด ๊ฐœ๋Ÿ‰์ฒด๋ฅผ ํ†ต๊ณผํ•œ ํ›„ ๋‚˜์˜จ ์œ ์ถœ์ˆ˜(outflow water)์— ํŽ˜๋†€ํ”„ํƒˆ๋ ˆ์ธ ์šฉ์•ก์„ ์ฃผ์ž…ํ•œ ๊ฒฝ์šฐ์—๋Š” ๋ถ‰์€์ƒ‰์œผ๋กœ ๋šœ๋ ทํžˆ ๋ฐ˜์‘ํ•˜๋Š” ๊ฒฐ๊ณผ๋ฅผ ๋ณด์˜€๋‹ค. ํŽ˜๋†€ํ”„ํƒˆ๋ ˆ์ธ ๋ฐ˜์‘ ์‹คํ—˜ ๊ฒฐ๊ณผ๋กœ๋ถ€ํ„ฐ ์ƒํ–ฅ ์นจํˆฌ๋กœ ์ธํ•ด ์œ ์ถœ์ˆ˜์˜ ์ผ๋ถ€๊ฐ€ ๊ฐœ๋Ÿ‰์ฒด๋ฅผ ํ†ต๊ณผํ•œ ํ›„ ๋ฐฐ์ถœ๋  ๋•Œ ๊ณ ํ™”์žฌ ์œ ์‹ค์ด ๋ฐœ์ƒํ•˜์˜€์Œ์„ ์•Œ ์ˆ˜ ์žˆ๋‹ค. ์ด์™€ ๊ฐ™์ด ํ”ผ์•• ์ž‘์šฉ์œผ๋กœ ์ธํ•ด ๊ณ ํ™”์žฌ ์šฉํƒˆ ํ˜„์ƒ์ด ๋ฐœ์ƒํ•  ๊ฒฝ์šฐ ์‹œ๋ฉ˜ํŠธ์˜ ๊ณ ํ™” ์ž‘์šฉ์ด ์ €ํ•˜๋  ์ˆ˜ ์žˆ์œผ๋ฉฐ ์ด๋Ÿฌํ•œ ๊ฒฐ๊ณผ๊ฐ€ ๊ฐœ๋Ÿ‰์ฒด์˜ ๊ฐ•๋„ ๋ฐœํ˜„์— ์˜ํ–ฅ์„ ๋ฏธ์ณค์„ ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

Fig. 7. The Relationship Between Secant Modulus and Unconfined Compressive Strength
../../Resources/KSCE/Ksce.2022.42.2.0187/fig7.png
Fig. 8. Geotechnical Characteristics according to Artesian Pressure
../../Resources/KSCE/Ksce.2022.42.2.0187/fig8.png
Fig. 9. Phenolphtalein Reaction Result
../../Resources/KSCE/Ksce.2022.42.2.0187/fig9.png

3.2 SEM ํŠน์„ฑ

์—ํŠธ๋ฆฐ์ž์ดํŠธ(ettringite, 3CaOยทAl2O3ยทCaSO4ยท32H2O)๋Š” ์‹œ๋ฉ˜ํŠธ์˜ ์ดˆ๊ธฐ ์ˆ˜ํ™”๋ฐ˜์‘(๊ฒฝํ™”๋ฐ˜์‘)์‹œ ์ƒ์„ฑ๋˜๋Š” ๋ฐ˜์‘ ์‚ฐ๋ฌผ๋กœ์„œ ์—ํŠธ๋ฆฐ์ž์ดํŠธ ์ƒ์„ฑ์€ ๊ฐœ๋Ÿ‰์ฒด์˜ ๊ฐ•๋„๋ฅผ ์ฆ๊ฐ€์‹œํ‚ค๊ณ  ์ˆ˜์ถ• ์ž‘์šฉ์„ ๋ฐฉ์ง€ํ•˜๋Š” ์•„์ฃผ ์ค‘์š”ํ•œ ๊ด‘๋ฌผ์ด๋‹ค. ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ํ”ผ์‚ฌ์ฒด์˜ ์‹ฌ๋„๊ฐ€ ๊นŠ๊ณ  ๋ฐฐ์œจ์ด ์ปค ์ž…์ฒด์ ์ธ ํ™”์ƒ์„ ์–ป์„ ์ˆ˜ ์žˆ๋Š” ์ฃผ์‚ฌ์ „์žํ˜„๋ฏธ๊ฒฝ(scanning electron microscope, SEM)์„ ํ†ตํ•ด Fig. 10๊ณผ ๊ฐ™์ด ๋น„ํ”ผ์•• ์กฐ๊ฑด ๋ฐ ํ”ผ์•• ์กฐ๊ฑด์— ๋”ฐ๋ฅธ ๊ฐœ๋Ÿ‰์ฒด์˜ ์ž…์ž๊ตฌ์กฐ ๋ฐ ๊ฒฐํ•ฉ์ƒํƒœ๋ฅผ ํ™•์ธํ•˜์˜€๋‹ค.

SEM ์ดฌ์˜์„ ํ†ตํ•ด ํ”ผ์••์˜ ์ž‘์šฉ ์œ ๋ฌด์— ๋”ฐ๋ฅธ ๊ฐœ๋Ÿ‰์ฒด์˜ ์ž…์ž ๊ตฌ์กฐ๋ฅผ ํ™•์ธํ•œ ๊ฒฐ๊ณผ ํ”ผ์••์ด ์ž‘์šฉํ•˜์ง€ ์•Š์€ ๊ฐœ๋Ÿ‰์ฒด์˜ ๊ฒฝ์šฐ ์—ํŠธ๋ฆฐ์ž์ดํŠธ์˜ ํ˜•์„ฑ์ด ์ž…์ž ์‚ฌ์ด์— ๊ณ ๋ฃจ ํ˜•์„ฑ๋˜์–ด ์žˆ๋Š” ๋ฐ˜๋ฉด, ํ”ผ์••์ด ์ž‘์šฉํ•œ ๊ฐœ๋Ÿ‰์ฒด(i = 0.5)์˜ ๊ฒฝ์šฐ ์—ํŠธ๋ฆฐ์ž์ดํŠธ๊ฐ€ ๋ถ€๋ถ„์ ์œผ๋กœ ํ˜•์„ฑ๋˜์–ด ์žˆ์œผ๋ฉฐ ํŠนํžˆ ์ž…์ž ์‚ฌ์ด์‚ฌ์ด์— ๊ณต๊ทน์ด ํ˜•์„ฑ๋˜์–ด ์žˆ๋Š” ๊ฒƒ์„ ํ™•์ธํ•  ์ˆ˜ ์žˆ๋‹ค. ์ด๋Ÿฌํ•œ ๊ฒฐ๊ณผ๋Š” ํ”ผ์•• ์ž‘์šฉ์‹œ ๊ฐœ๋Ÿ‰์ฒด ์ž…์ž ์‚ฌ์ด์— ๋ฌผ์ด ์นจํˆฌ๋˜์–ด ๊ณ ํ™”์žฌ๊ฐ€ ๋ถ€๋ถ„ ์œ ์‹ค๋จ์œผ๋กœ์จ ์—ํŠธ๋ฆฐ์ž์ดํŠธ์˜ ํ˜•์„ฑ๊ณผ ์ž…์ž๊ฐ„์˜ ๊ฒฐ์†์„ ์ €ํ•ดํ•˜์—ฌ ๋‚˜ํƒ€๋‚œ ๊ฒฐ๊ณผ๋กœ ํŒ๋‹จ๋œ๋‹ค. ๋˜ํ•œ 3.1์ ˆ์—์„œ ์„ค๋ช…ํ•œ ํ”ผ์••์ด ์ž‘์šฉํ•˜๋Š” ๊ฐœ๋Ÿ‰์ฒด์˜ ํ•จ์ˆ˜๋น„ ์ฆ๊ฐ€์™€ ๊ฐ•๋„ ๋ฐ ๋‹จ์œ„์ค‘๋Ÿ‰ ๊ฐ์†Œ ๊ฒฐ๊ณผ์™€๋„ ์—ฐ๊ด€๋œ๋‹ค.

Fig. 10. SEM Result
../../Resources/KSCE/Ksce.2022.42.2.0187/fig10.png

3.3 ํ”ผ์••์— ์˜ํ•œ ๋ณด์ผ๋ง(boiling) ํ˜„์ƒ

ํ”ผ์••์ด ์ž‘์šฉํ•˜๋Š” ์ง€์ธต์— ์ง€๋ฐ˜๊ฐœ๋Ÿ‰๊ณต์‚ฌ๋ฅผ ์œ„ํ•ด ๋“œ๋ฆด๋ง(drilling) ๋“ฑ์„ ํ†ตํ•œ ๊ต๋ฐ˜์„ ์‹ค์‹œํ•  ๊ฒฝ์šฐ ํ”ผ์••์— ์˜ํ•ด ๋ถ€๋ถ„์ ์œผ๋กœ ํฐ ๋™์ˆ˜๊ฒฝ์‚ฌ๊ฐ€ ๋ฐœ์ƒํ•  ์ˆ˜ ์žˆ์œผ๋ฉฐ, ์ด๋กœ ์ธํ•ด ์ง€๋ฐ˜์˜ ๋ณด์ผ๋ง(boiling) ํ˜„์ƒ์ด ๋ฐœ์ƒํ•  ์ˆ˜ ์žˆ๋‹ค. ๋ณด์ผ๋ง์€ ์‚ฌ์งˆํ†  ์ง€๋ฐ˜์—์„œ ์ง€ํ•˜์ˆ˜๊ฐ€ ๋ฐ”๋‹ฅ๋ฉด์œผ๋กœ ๋ชจ๋ž˜์™€ ํ•จ๊ป˜ ์†Ÿ์•„์˜ค๋ฅด๋Š” ์ง€๋ฐ˜ ์œต๊ธฐ ํ˜„์ƒ์œผ๋กœ ์ฃผ๋กœ ์ง€ํ•˜์ˆ˜์œ„์˜ ์ฐจ์ด๊ฐ€ ๋†’์€ ์—ฐ์•ฝ ์‚ฌ์งˆํ†  ์ง€๋ฐ˜์—์„œ ๋ฐœ์ƒํ•œ๋‹ค. ์ง€๋ฐ˜๊ตด์ฐฉ์‹œ ์ง€ํ•˜์ˆ˜์œ„ ๋“ฑ์— ์˜ํ•ด ๋ฌผ์ด ์œ ์ž…๋˜์–ด ๋ณด์ผ๋ง์ด ๋ฐœ์ƒํ•˜๊ฒŒ ๋  ๊ฒฝ์šฐ ์ง€๋ฐ˜์˜ ํฌ๊ณ  ์ž‘์€ ๋ถ•๊ดด ์‚ฌ๊ณ  ๋“ฑ์ด ์œ ๋ฐœ๋  ์ˆ˜ ์žˆ์œผ๋ฏ€๋กœ ์ด์— ๋Œ€ํ•œ ์˜ˆ๋ฐฉ ๋ฐ ๊ฒ€ํ† ๋ฅผ ์ˆ˜ํ–‰ํ•˜์—ฌ์•ผ ํ•œ๋‹ค(Ham, 2019; Kim et al., 2017; Seong et al., 2011).

Fig. 11์€ ์ƒ๋Œ€์ ์œผ๋กœ ๋†’์€ ํ”ผ์••(i = 5.0)์—์„œ ๋ฐœ์ƒํ•œ ๋ณด์ผ๋ง ํ˜„์ƒ์œผ๋กœ ์ƒํ–ฅ์œผ๋กœ ์œ ์ถœ๋œ ๊ณต์‹œ์ฒด์˜ ์ผ๋ถ€๋ถ„์ด๋‹ค. ๊ฐœ๋Ÿ‰์ฒด์— ํ”ผ์••์ด ํฌ๊ฒŒ ์ž‘์šฉํ•œ ๊ฒฐ๊ณผ ์‹œ๋ฃŒ์˜ ์ผ๋ถ€๊ฐ€ ๋ณด์ผ๋ง๋˜์–ด ์œ ์‹ค๋˜์—ˆ์œผ๋ฉฐ(Fig. 11(a)) ์ด๋กœ ์ธํ•ด ๊ฐœ๋Ÿ‰์ฒด์˜ ์••์ถ•๊ฐ•๋„ ์‹œํ—˜์ด ๋ถˆ๊ฐ€๋Šฅํ•œ ์ƒํƒœ(Fig. 11(b))๊ฐ€ ๋˜์—ˆ๋‹ค. ์ด์™€ ๊ฐ™์ด ์ˆœ๊ฐ„์ ์œผ๋กœ ์•„์ฃผ ํฐ ํ”ผ์••์ด ์ž‘์šฉํ•  ๊ฒฝ์šฐ ์‹œ๋ฃŒ์˜ ์œ ์‹ค์ด ํฌ๊ฒŒ ๋ฐœ์ƒํ•˜๋ฉฐ, ์ง€๋ฐ˜ ๊ฐœ๋Ÿ‰์ด ์›ํ™œํ•˜๊ฒŒ ์ด๋ฃจ์–ด์ง€์ง€ ์•Š์„ ์ˆ˜ ์žˆ์œผ๋ฏ€๋กœ ์ฃผ์˜ํ•ด์•ผ ํ•œ๋‹ค.

๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ์‹ค๋‚ด์‹คํ—˜์„ ํ†ตํ•ด ํ”ผ์••์ด ๊ฐœ๋Ÿ‰์ฒด์˜ ์—ญํ•™์  ํŠน์„ฑ์— ๋ฏธ์น˜๋Š” ์ „๋ฐ˜์ ์ธ ๊ฒฝํ–ฅ์„ ์‹ค๋‚ด์‹คํ—˜์„ ํ†ตํ•ด ์•Œ์•„๋ณธ ๊ฒƒ์œผ๋กœ ์ง€๋ฐ˜๊ณตํ•™์  ๊ฑฐ๋™ ํŠน์„ฑ์„ ์˜ˆ์ธกํ•˜๊ธฐ ์œ„ํ•œ ๊ธฐ์ดˆ ์ž๋ฃŒ๋กœ ํ™œ์šฉํ•  ์ˆ˜ ์žˆ์„ ๊ฒƒ์œผ๋กœ ๊ธฐ๋Œ€๋œ๋‹ค. ํ•˜์ง€๋งŒ ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ๋Œ€์ƒ ์ง€์—ญ์—์„œ ๋ถ€๋ถ„์ ์œผ๋กœ ์ฑ„์ทจ๋œ ์‹œ๋ฃŒ๋ฅผ ์‚ฌ์šฉํ•˜์—ฌ ์‹ค๋‚ด์‹คํ—˜์„ ์ˆ˜ํ–‰ํ•˜์˜€์œผ๋ฏ€๋กœ ์ผ๋ฐ˜ํ™”ํ•˜๊ธฐ์—๋Š” ํ•œ๊ณ„๊ฐ€ ์žˆ๋‹ค. ๋”ฐ๋ผ์„œ ํ˜„์žฅ์˜ ์ง€์ธต ์กฐ๊ฑด ๋ฐ ํ”ผ์••์˜ ์ž‘์šฉ ๋ฐฉ๋ฒ• ๋“ฑ ์ถ”๊ฐ€์ ์ธ ์‹คํ—˜ ๋ฐ ๋ถ„์„์„ ์ˆ˜ํ–‰ํ•ด์•ผ ํ•  ํ•„์š”๊ฐ€ ์žˆ๋‹ค.

Fig. 11. Boiling Effect Under a High Hydraulic Gradient
../../Resources/KSCE/Ksce.2022.42.2.0187/fig11.png

4. ๊ฒฐ ๋ก 

๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ํ”ผ์••์ด DCM ๊ฐœ๋Ÿ‰์ฒด(๋ชจ๋ž˜, ์ ํ† )์˜ ์—ญํ•™์  ํŠน์„ฑ(์ผ์ถ•์••์ถ•๊ฐ•๋„, ํ•จ์ˆ˜๋น„, ๋‹จ์œ„์ค‘๋Ÿ‰, ํ• ์„ ํƒ„์„ฑ๊ณ„์ˆ˜)์— ๋ฏธ์น˜๋Š” ์˜ํ–ฅ์„ ์•Œ์•„๋ณด๊ธฐ ์œ„ํ•ด ํ”ผ์•• ํฌ๊ธฐ์˜ ์ œ์–ด๊ฐ€ ๊ฐ€๋Šฅํ•œ ๊ณต์‹œ์ฒด์šฉ ์ˆ˜์กฐ๋ฅผ ์ œ์ž‘ํ•˜์—ฌ ๋‹ค์–‘ํ•œ ์‹ค๋‚ด์‹คํ—˜์„ ์ˆ˜ํ–‰ํ•˜์˜€์œผ๋ฉฐ, ๊ทธ ๊ฒฐ๊ณผ๋Š” ๋‹ค์Œ๊ณผ ๊ฐ™๋‹ค.

(1) ํ”ผ์•• ํฌ๊ธฐ์— ๋”ฐ๋ฅธ ๊ฐœ๋Ÿ‰์ฒด์˜ ์‘๋ ฅ-๋ณ€ํ˜• ๊ฑฐ๋™์„ ์‚ดํŽด๋ณด๋ฉด ํ”ผ์••์ด ์ž‘์šฉํ•˜์ง€ ์•Š๋Š” ๊ฐœ๋Ÿ‰์ฒด์˜ ๊ฒฝ์šฐ ์ทจ์„ฑ์ ์ธ ๊ฑฐ๋™(brittle behavior) ํ˜•ํƒœ๋ฅผ ๋ณด์ธ ๋ฐ˜๋ฉด, ํ”ผ์••์ด ์ฆ๊ฐ€ํ• ์ˆ˜๋ก ํŒŒ๊ดด์‹œ ์ถ•๋ณ€ํ˜•๋ฅ ์ด ์ ์ฐจ ์ฆ๊ฐ€ํ•˜๋Š” ์—ฐ์„ฑ์ ์ธ ๊ฑฐ๋™(ductile behavior)์„ ๋ณด์˜€๋‹ค.

(2) ๋ชจ๋ž˜ ๋ฐ ์ ํ†  ๊ฐœ๋Ÿ‰์ฒด์˜ ํ• ์„ ํƒ„์„ฑ๊ณ„์ˆ˜๋Š” ๊ฐ๊ฐ ์ผ์ถ•์••์ถ•๊ฐ•๋„์˜ 100~146๋ฐฐ ๋ฐ 90~123๋ฐฐ ์ •๋„์˜ ๋ฒ”์œ„๋กœ ๊ฐ๊ฐ ๋‚˜ํƒ€๋‚ฌ๋‹ค. ๋˜ํ•œ ํ”ผ์••์˜ ํฌ๊ธฐ๊ฐ€ ์ปค์งˆ์ˆ˜๋ก ํ• ์„ ํƒ„์„ฑ๊ณ„์ˆ˜์™€ ์ผ์ถ•์••์ถ•๊ฐ•๋„ ๊ด€๊ณ„ ๊ทธ๋ž˜ํ”„์˜ ๊ธฐ์šธ๊ธฐ๋Š” ์ ์ฐจ ๊ฐ์†Œํ•˜๋Š” ๊ฒฝํ–ฅ์„ ๋ณด์˜€๋‹ค.

(3) ํ”ผ์••์ด ์ฆ๊ฐ€ํ• ์ˆ˜๋ก ๊ฐœ๋Ÿ‰์ฒด์˜ ์ผ์ถ•์••์ถ•๊ฐ•๋„์™€ ๋‹จ์œ„์ค‘๋Ÿ‰์€ ๊ฐ์†Œํ•˜๋‚˜, ํ•จ์ˆ˜๋น„๋Š” ์ฆ๊ฐ€ํ•˜์˜€๋‹ค. ์ด๋Ÿฌํ•œ ๊ฒฐ๊ณผ๋Š” ํ”ผ์••์ด ๊ฐ๊ฐ ๋ชจ๋ž˜ ๋ฐ ์ ํ†  ๊ฐœ๋Ÿ‰์ฒด์— ์ž‘์šฉํ•จ์— ๋”ฐ๋ผ ๊ณต์‹œ์ฒด์˜ ํ•˜๋‹จ๋ถ€๊ฐ€ ์ทจ์•ฝํ•ด์ ธ ํ•จ์ˆ˜๋น„, ๋‹จ์œ„์ค‘๋Ÿ‰ ๋ฐ ์••์ถ•๊ฐ•๋„์— ์˜ํ–ฅ์„ ๋ฏธ์น˜๊ฒŒ ๋œ ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

(4) ๊ฐœ๋Ÿ‰์ฒด์˜ ํ”ผ์••์— ์˜ํ•œ ์šฉํƒˆ ํ˜„์ƒ์„ ํ™•์ธํ•˜๊ธฐ ์œ„ํ•ด ์ˆ˜ํ–‰ํ•œ ํŽ˜๋†€ํ”„ํƒˆ๋ ˆ์ธ ๋ฐ˜์‘ ์‹คํ—˜์—์„œ ํ”ผ์•• ์ž‘์šฉ ํ›„ ๋‚˜์˜จ ์œ ์ถœ์ˆ˜๋Š” ๋ถ‰์€์ƒ‰์œผ๋กœ ๋šœ๋ ทํ•˜๊ฒŒ ๋ฐ˜์‘ํ•˜๋Š” ๊ฒฐ๊ณผ๋ฅผ ๋ณด์˜€๋‹ค. ์ด๋ฅผ ํ†ตํ•ด ๊ณ ํ™”์žฌ์˜ ์ผ๋ถ€๊ฐ€ ์œ ์‹ค๋œ ๊ฒƒ์„ ์•Œ ์ˆ˜ ์žˆ๋‹ค.

(5) ํ”ผ์••์˜ ์ž‘์šฉ ์œ ๋ฌด์— ๋”ฐ๋ฅธ ๊ฐœ๋Ÿ‰์ฒด์˜ ํŒŒ๊ดด ๋‹จ๋ฉด์— ๋Œ€ํ•˜์—ฌ SEM ์ดฌ์˜์„ ํ•œ ๊ฒฐ๊ณผ, ๋น„ํ”ผ์•• ์กฐ๊ฑด์— ๋น„ํ•ด ํ”ผ์••(i = 0.5)์ด ์ž‘์šฉํ•œ ๊ฐœ๋Ÿ‰์ฒด์˜ ๊ฒฝ์šฐ ์—ํŠธ๋ฆฐ์ž์ดํŠธ์˜ ๋ฐœํ˜„์ด ํฌ๊ฒŒ ๊ฐ์†Œํ•˜์˜€์œผ๋ฉฐ, ์ž…์ž ์‚ฌ์ด ๊ณต๊ทน์ด ์ฆ๊ฐ€ํ•˜๋Š” ๊ฒฝํ–ฅ์„ ๋ณด์˜€๋‹ค.

๊ฐ์‚ฌ์˜ ๊ธ€

์ด ๋…ผ๋ฌธ์€ ๋ถ€๊ฒฝ๋Œ€ํ•™๊ต ์ž์œจ์ฐฝ์˜ํ•™์ˆ ์—ฐ๊ตฌ๋น„(2021๋…„)์— ์˜ํ•˜์—ฌ ์—ฐ๊ตฌ๋˜์—ˆ์Šต๋‹ˆ๋‹ค.

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