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

  1. ์ œ์ฃผ๋Œ€ํ•™๊ต ํ† ๋ชฉ๊ณตํ•™๊ณผ ๋ฐ•์‚ฌ๊ณผ์ • (Jeju National University)
  2. ์ œ์ฃผ๋Œ€ํ•™๊ต ํ† ๋ชฉ๊ณตํ•™๊ณผ ๊ต์ˆ˜ (Jeju National University)


๋งค์ž…๋ง๋š, ์ฃผ๋ฉด์ง€์ง€๋ ฅ, ์ฃผ๋ฉด๊ณ ์ •์•ก, ๋ฐฐํ•ฉ๋น„, ์‹œ๋ฉ˜ํŠธํ’€, ๋ชจ๋ฅดํƒ€๋ฅด
Drilled-in pile, Shaft resistance, Grouting material, Mix proportion, Cement paste, Mortar

  • 1. ์„œ ๋ก 

  • 2. ๊ธฐ์กด ์—ฐ๊ตฌ ๋ฐ ์„ค๊ณ„๊ธฐ์ค€

  • 3. ์‹คํ—˜๊ณ„ํš

  •   3.1 ์•”๋ฐ˜๋งค์ž…๋ง๋š์˜ ์ฃผ๋ฉดํŒŒ๊ดด

  •   3.2 ์‹คํ—˜์ฒด ๋ฐ ๋ณ€์ˆ˜

  •   3.3 ์‚ฌ์šฉ์žฌ๋ฃŒ

  •   3.4 ์‹คํ—˜๋ฐฉ๋ฒ• ๋ฐ ์žฅ์น˜

  • 4. ์‹คํ—˜๊ฒฐ๊ณผ ๋ฐ ๊ณ ์ฐฐ

  •   4.1 ๋งค์ž…๋ง๋š์˜ ๋ถ€์ฐฉ๋ฉด์ 

  •   4.2 ๋งค์ž…๋ง๋š์˜ ์ฃผ๋ฉด์ง€์ง€๊ฑฐ๋™

  •   4.3 ๋ฐฐํ•ฉ๋น„์— ๋”ฐ๋ฅธ ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ

  •   4.4 ๋ฐฐํ•ฉ๋น„์— ๋”ฐ๋ฅธ ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ

  •   4.5 ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ vs. ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ

  • 5. ๊ฒฐ ๋ก 

1. ์„œ ๋ก 

ํ’๋ ฅ๋ฐœ์ „๊ธฐ, ์†ก์ „ํƒ‘, ๊ตด๋š ๋“ฑ๊ณผ ๊ฐ™์€ ํƒ€์›Œ ๊ตฌ์กฐ๋ฌผ์€ ํญ์— ๋น„ํ•˜์—ฌ ๋†’์ด๊ฐ€ ๋†’์€ ๊ตฌ์กฐ๋ฌผ๋กœ์„œ, ์™ธ๋ ฅ์— ์˜ํ•ด ์ „๋„๋ชจ๋ฉ˜ํŠธ๊ฐ€ ํฌ๊ฒŒ ๋ฐœ์ƒํ•œ๋‹ค. ์ด๋Ÿฌํ•œ ๊ตฌ์กฐ๋ฌผ์„ ์ง€์ง€ํ•˜๊ธฐ ์œ„ํ•ด์„œ๋Š” ์ƒ๋Œ€์ ์œผ๋กœ ํฌ๊ธฐ๊ฐ€ ํฐ ์ค‘๋ ฅ์‹ ๊ธฐ์ดˆ๋ฅผ ์‚ฌ์šฉํ•˜๊ฑฐ๋‚˜ ๋ง๋š ๊ธฐ์ดˆ๋ฅผ ์‚ฌ์šฉํ•ด์•ผ ํ•œ๋‹ค. ์ค‘๋ ฅ์‹ ๊ธฐ์ดˆ๋ฅผ ์‚ฌ์šฉํ•˜๊ธฐ ์œ„ํ•ด์„œ๋Š” ๋„“์€ ๋ถ€์ง€์™€ ๋ถ€์ง€ ๊ตด์ฐฉ์ž‘์—…์ด ์š”๊ตฌ๋˜๋Š”๋ฐ, ๊ธฐ์ดˆ๋ถ€์ง€๊ฐ€ ์ œํ•œ์ ์ด๊ฑฐ๋‚˜ ์ง€๋ฐ˜์ด ์•”๋ฐ˜์œผ๋กœ ๊ตฌ์„ฑ๋œ ๊ฒฝ์šฐ์—๋Š” ์ค‘๋ ฅ์‹ ๊ธฐ์ดˆ์— ๋ง‰๋Œ€ํ•œ ๊ณต์‚ฌ๋น„๊ฐ€ ์†Œ์š”๋œ๋‹ค. ์ด๋Ÿฌํ•œ ๊ฒฝ์šฐ ๋ง๋š๊ธฐ์ดˆ๋Š” ์ฐจ์ง€ํ•˜๋Š” ๋ฉด์ ์ด ์ž‘๊ณ  ๊ฒฝ์ œ์ ์ธ ์žฅ์ ์„ ๊ฐ€์ง€๊ณ  ์žˆ๋‹ค. ๋ง๋š๊ธฐ์ดˆ๋Š” ํƒ€์›Œ ๊ตฌ์กฐ๋ฌผ์— ์ž‘์šฉํ•˜๋Š” ์ „๋„๋ชจ๋ฉ˜ํŠธ์— ๋Œ€ํ•ด ์„œ๋กœ ๋–จ์–ด์ ธ ์žˆ๋Š” ๋ง๋š์˜ ์••์ถ•๋ ฅ๊ณผ ์ธ๋ฐœ๋ ฅ, ๊ทธ๋ฆฌ๊ณ  ์ˆ˜ํ‰๋ ฅ์œผ๋กœ ์ €ํ•ญํ•˜๊ฒŒ ๋œ๋‹ค. ํŠนํžˆ, ๊ตญ๋‚ด ํ•ด์ƒํ’๋ ฅ๋ฐœ์ „๊ธฐ์˜ ๊ฒฝ์šฐ Fig. 1์— ๋‚˜ํƒ€๋‚ธ ๊ฒƒ๊ณผ ๊ฐ™์€ Jacket ๊ตฌ์กฐ๋ฌผ์„ ์ฃผ๋กœ ์ฑ„ํƒํ•˜๊ณ  ์žˆ์œผ๋ฉฐ, ํฐ ์ˆ˜ํ‰๋ ฅ๊ณผ ํฐ ์ „๋„๋ชจ๋ฉ˜ํŠธ๋ฅผ ์ง€์ง€ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ 3, 4๊ฐœ์˜ ๋‹ค๋ฆฌ์— ๊ฐ๊ฐ ์•”๋ฐ˜๋งค์ž… ๊ฐ•๊ด€๋ง๋š์„ ์ด์šฉํ•˜์—ฌ ์ง€์ง€ํ•˜๊ณ  ์žˆ๋‹ค. ๊ทธ๋ฆผ์—์„œ ๋ณด๋Š” ๋ฐ”์™€ ๊ฐ™์ด ํ•˜์ค‘์ž‘์šฉ์ (๋กœํ„ฐ)์—์„œ ์ง€์ง€์ (ํ•ด์ €๋ฉด)๊นŒ์ง€์˜ ๊ฑฐ๋ฆฌ๋Š” ์ˆ˜์‹ฌ์œผ๋กœ ์ธํ•ด ๋” ๋ฉ€์–ด์ง€๊ฒŒ ๋˜๊ณ , ์ด๋กœ ์ธํ•ด ์ƒ๋Œ€์ ์œผ๋กœ ๋” ํฐ ์ „๋„๋ชจ๋ฉ˜ํŠธ๋ฅผ ์ง€์ง€ํ•ด์•ผ ํ•œ๋‹ค. ๋˜ํ•œ ํ•ด์ƒ์—์„œ ์ž‘์—…์ด ์ด๋ฃจ์–ด์ง€๋ฏ€๋กœ ๋ณด๋‹ค ์•ˆ์ „ํ•˜๊ณ  ๊ฒฝ์ œ์ ์ธ ์‹œ๊ณต์„ ์œ„ํ•ด์„œ๋Š” ๋ง๋š์˜ ์ง€์ง€๋ ฅ์„ ์ •ํ™•ํ•˜๊ฒŒ ์ถ”์ •ํ•˜์—ฌ ๋ง๋š์„ ์„ค๊ณ„ํ•˜๋Š” ๊ฒƒ์ด ํ•„์š”ํ•œ ์‹ค์ •์ด๋‹ค. ํŠนํžˆ, ์ธ๋ฐœ๋ ฅ์˜ ๊ฒฝ์šฐ๋Š” ๋ง๋š์˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์œผ๋กœ๋งŒ ๊ฒฐ์ •๋˜๊ธฐ ๋•Œ๋ฌธ์— ์ด์— ๋Œ€ํ•œ ์ง€์ง€๋ ฅ ํ‰๊ฐ€๊ฐ€ ๋”์šฑ ์ ˆ์‹คํ•˜๋‹ค.

Fig. 1.

Jacket for Offshore Wind Turbine

Figure_KSCE_38_01_06_F1.jpg

๋”ฐ๋ผ์„œ, ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ์•”๋ฐ˜์— ๋งค์ž…๋œ ๊ฐ•๊ด€๋ง๋š์˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์„ ์˜ˆ์ธกํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ๋ชจํ˜•์‹คํ—˜์„ ์ˆ˜ํ–‰ํ•˜๊ณ  ์ฃผ๋ฉด๊ณ ์ •์•ก์˜ ๋ฐฐํ•ฉ๋น„์— ๋”ฐ๋ฅธ ์˜ํ–ฅ์„ ํ‰๊ฐ€ํ•˜๊ณ ์ž ํ•œ๋‹ค.

2. ๊ธฐ์กด ์—ฐ๊ตฌ ๋ฐ ์„ค๊ณ„๊ธฐ์ค€

๋ง๋š์˜ ์ง€์ง€๋ ฅ์— ๋Œ€ํ•œ ์—ฐ๊ตฌ๋Š” ์˜ค๋žœ ๊ธฐ๊ฐ„ ๋™์•ˆ ์ˆ˜๋งŽ์€ ์—ฐ๊ตฌ์ž๋“ค์— ์˜ํ•ด ์—ฐ๊ตฌ๊ฐ€ ์ง„ํ–‰๋˜์–ด ์™”์œผ๋ฉฐ, ํ† ์‚ฌ์ง€๋ฐ˜์˜ ๊ฒฝ์šฐ ์‹คํ—˜๊ฐ’์„ ํ† ๋Œ€๋กœ ๊ธฐ์ดˆ์„ค๊ณ„ ์ด๋ก ์ด ์ •๋ฆฝ๋˜์–ด ์žˆ๋‹ค. ๋˜ํ•œ, ์•”๋ฐ˜์— ๊ทผ์ž…๋œ ๋ง๋š์— ๋Œ€ํ•œ ์—ฐ๊ตฌ๋Š” ํ˜„์žฅํƒ€์„ค๋ง๋š์„ ๋Œ€์ƒ์œผ๋กœ ํ•œ ์—ฐ๊ตฌ๊ฐ€ ์ฃผ๋ฅผ ์ด๋ฃจ๊ณ  ์žˆ์œผ๋ฉฐ, ์•”๋ฐ˜์— ๊ทผ์ž…๋œ ํ˜„์žฅํƒ€์„ค๋ง๋š์˜ ๊ทนํ•œ์ง€์ง€๋ ฅ์— ๋Œ€ํ•œ ์‹์€ ๊ตฌ์กฐ๋ฌผ๊ธฐ์ดˆ์„ค๊ณ„๊ธฐ์ค€(KGS, 2015)์—์„œ Table 1๊ณผ ๊ฐ™์ด ์ •๋ฆฌํ•˜๊ณ  ์žˆ๋‹ค. ๋˜ํ•œ ๊ตฌ์กฐ๋ฌผ๊ธฐ์ดˆ์„ค๊ณ„๊ธฐ์ค€(KGS, 2015)์—์„œ๋Š” ์—ฐ์•”๋ฐ˜์— ๊ทผ์ž…๋œ ๊ฐ•๊ด€๋ง๋š์— ๋Œ€ํ•œ ๊ทนํ•œ์„ ๋‹จ์ง€์ง€๋ ฅ ์‚ฐ์ •์‹์„ ๊ฒฝํ—˜์‹์œผ๋กœ ์ œ์‹œํ•˜์˜€์œผ๋ฉฐ, ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์€ ์„ ๋‹จ์ง€์ง€๋ ฅ ๊ฐ’์— ํฌํ•จ๋œ ๊ฒƒ์œผ๋กœ ๊ฐ„์ฃผํ•˜๊ณ  ์žˆ๋‹ค. ๋”ฐ๋ผ์„œ ํ˜„ํ–‰ ์„ค๊ณ„๊ธฐ์ค€์œผ๋กœ๋Š” ์•”๋ฐ˜์— ๋ง๋š์„ ๋งค์ž…ํ•˜๊ณ  ์ฃผ๋ฉด์„ ๊ทธ๋ผ์šฐํŒ…ํ•œ ๊ฒฝ์šฐ์— ๋Œ€ํ•ด์„œ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์„ ํ‰๊ฐ€ํ•  ์ˆ˜ ์—†์œผ๋ฉฐ, ์ธ๋ฐœ์ง€์ง€๋ ฅ์— ๋Œ€ํ•œ ์ถ”์ • ๋˜ํ•œ ๋งค์šฐ ์–ด๋ ค์šด ์ƒํƒœ์ด๋‹ค.

Table 1. Side Resistance of Drilled Shafts in Rock (KGS, 2015) Table_KSCE_38_01_06_T1.jpg

: Uniaxial compressive strength (UCS) of rock,

: Atmospheric pressure,

: The smaller of UCS of rock and concrete,

: UCS of concrete at 28-days,

: Coefficient of friction

: Drilled shaft of length

์•”๋ฐ˜๋งค์ž…๋ง๋š์˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์— ๋Œ€ํ•œ ์—ฐ๊ตฌ๋Š” ๋งค์šฐ ๋ถ€์กฑํ•œ ์‹ค์ •์ด๋ฉฐ, ์•”๋ฐ˜์— ๊ฐ•๊ด€๋ง๋š์ด ๋งค์ž…๋œ ๊ฒฝ์šฐ์— ๋Œ€ํ•ด์„œ Maertens(2002)์ด ๋ฐœํ‘œํ•œ ๋ฐ” ์žˆ๋‹ค. Maertens(2002)๋Š” ํ’ํ™”๋œ ํ˜„๋ฌด์•”์— ๊ฐ•๊ด€๋ง๋š์„ ์„ค์น˜ํ•œ ๊ฒฝ์šฐ ๋ง๋š์˜ ์„ฑ๋Šฅ์„ ํ‰๊ฐ€ํ•˜๊ณ  ์‹œ๊ณต ์ œ์›์„ ๊ฒฐ์ •ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ํ˜„์žฅ์‹œํ—˜(์••์ถ•, ์ธ๋ฐœ)์„ ์ˆ˜ํ–‰ํ•˜์˜€์œผ๋‚˜, ์ ์šฉํ˜„์žฅ์— ๋Œ€ํ•œ ์„ฑ๋Šฅํ‰๊ฐ€๋งŒ ํ•˜์˜€๋‹ค๋Š” ํ•œ๊ณ„๊ฐ€ ์žˆ์—ˆ๋‹ค. Moon et al.(2014)์€ ์•”๋ฐ˜๋งค์ž… ๊ฐ•๊ด€๋ง๋š์˜ ๊ทนํ•œ์ฃผ๋ฉด์ง€์ง€๋ ฅ์€ ๊ฐ•๊ด€๊ณผ ์ฃผ๋ฉด๊ณ ์ •์•ก ์‚ฌ์ด์˜ ๋ถ€์ฐฉ๋ ฅ์— ์˜ํ•ด ๊ฒฐ์ •๋œ๋‹ค๊ณ  ๋ฐœํ‘œํ•œ ๋ฐ”๊ฐ€ ์žˆ๋‹ค. Moon et al.(2014)์€ ์•”๋ฐ˜์— ๊ฐ•๊ด€์ด ์‚ฝ์ž…๋œ ๊ฒฝ์šฐ ์ฃผ๋ฉด์ง€์ง€๊ฑฐ๋™์„ ๋ชจํ˜•์‹คํ—˜์„ ํ†ตํ•ด ํ‰๊ฐ€ํ•˜์˜€์œผ๋ฉฐ, ์•ฝ 1MPa์˜ ๋ถ€์ฐฉ๊ฐ•๋„๋ฅผ ๋‚˜ํƒ€๋ƒˆ๋‹ค. Shakir-Khalil(1993a, 1993b)์™€ Nezamian et al.(2002)๋Š” ๊ฐ•๊ด€ ์†์— ์ฝ˜ํฌ๋ฆฌํŠธ๊ฐ€ ์ฑ„์›Œ์กŒ์„ ๋•Œ ์ฝ˜ํฌ๋ฆฌํŠธ์™€ ๊ฐ•๊ด€ ์‚ฌ์ด์˜ ๋ถ€์ฐฉ๊ฐ•๋„์— ๋Œ€ํ•ด ๋งค์ž…์กฐ๊ฑด์„ ๋ณ€์ˆ˜๋กœ ํ•˜์—ฌ ์‹คํ—˜์—ฐ๊ตฌ๋ฅผ ์ˆ˜ํ–‰ํ•˜์—ฌ ๊ฐ•๊ด€๊ณผ ์ฝ˜ํฌ๋ฆฌํŠธ์˜ ๋ถ€์ฐฉ๊ฑฐ๋™์— ๋Œ€ํ•ด ์ •๋ฆฌํ•˜์˜€๋‹ค.

๊ธฐ์กด ์—ฐ๊ตฌ์˜ ๊ฒฝ์šฐ, ์•”๋ฐ˜์— ๊ฐ•๊ด€๋ง๋š์„ ์„ค์น˜ํ•˜์—ฌ ์ง€์ง€์„ฑ๋Šฅ์„ ํ‰๊ฐ€ํ•˜์˜€์œผ๋‚˜ ์ง€์ง€๋ ฅ์— ๋ฏธ์น˜๋Š” ์˜ํ–ฅ์ธ์ž์— ๋Œ€ํ•œ ํ‰๊ฐ€๊ฐ€ ๋ฏธํกํ•˜์˜€๋‹ค. ๋”ฐ๋ผ์„œ, ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ์ฃผ๋ฉด๊ณ ์ •์•ก์˜ ๋ฐฐํ•ฉ๋น„๊ฐ€ ์•”๋ฐ˜๋งค์ž… ๊ฐ•๊ด€๋ง๋š์˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์— ๋ฏธ์น˜๋Š” ์˜ํ–ฅ์„ ํ‰๊ฐ€ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ์‹œ๋ฉ˜ํŠธ, ๋ฌผ, ์ž”๊ณจ์žฌ(๋ชจ๋ž˜)์˜ ๋ฐฐํ•ฉ๋น„๋ฅผ ๋‹ฌ๋ฆฌํ•˜์—ฌ ๋ชจํ˜•์‹คํ—˜์„ ์ˆ˜ํ–‰ํ•˜์˜€์œผ๋ฉฐ, ๊ทธ ๊ฒฐ๊ณผ๋ฅผ ๋ถ„์„ํ•˜์—ฌ ์•”๋ฐ˜๋งค์ž… ๊ฐ•๊ด€๋ง๋š์˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ ์‚ฐ์ •์˜ ๊ธฐ์ดˆ์ž๋ฃŒ๋กœ ์ œ์‹œํ•˜๊ณ ์ž ํ•œ๋‹ค.

3. ์‹คํ—˜๊ณ„ํš

3.1 ์•”๋ฐ˜๋งค์ž…๋ง๋š์˜ ์ฃผ๋ฉดํŒŒ๊ดด

์•”๋ฐ˜์— ๋งค์ž…๋œ ๊ฐ•๊ด€๋ง๋š์˜ ์ฃผ๋ฉดํŒŒ๊ดด๋Š” Fig. 2์— ๋‚˜ํƒ€๋‚ธ ๊ฒƒ๊ณผ ๊ฐ™์ด 4๊ฐ€์ง€ ํ˜•ํƒœ๋กœ ๋‚˜ํƒ€๋‚  ์ˆ˜ ์žˆ๋‹ค. ๋จผ์ €, ๊ฐ•๊ด€๊ณผ ์ฃผ๋ฉด๊ณ ์ •์•ก ์‚ฌ์ด์˜ ๋ถ€์ฐฉํŒŒ๊ดด, ์ฃผ๋ฉด๊ณ ์ •์•ก ์ž์ฒด์˜ ์ „๋‹จํŒŒ๊ดด, ์•”๋ฐ˜๊ณผ ์ฃผ๋ฉด๊ณ ์ •์•ก ์‚ฌ์ด์˜ ๋ถ€์ฐฉํŒŒ๊ดด, ๋งˆ์ง€๋ง‰์œผ๋กœ ์•”๋ฐ˜ ์ž์ฒด์˜ ์ „๋‹จํŒŒ๊ดด์ด๋‹ค. ๊ฐ ๋ถ€๋ถ„์˜ ์ €ํ•ญ๋ ฅ ์ค‘ ๊ฐ€์žฅ ์ž‘์€ ๊ฐ’์„ ๋‚˜ํƒ€๋‚ด๋Š” ๋ถ€๋ถ„์—์„œ ์ฃผ๋ฉดํŒŒ๊ดด๊ฐ€ ๋ฐœ์ƒํ•  ๊ฒƒ์ด๋‹ค.

Fig. 2.

Failure Mode

Figure_KSCE_38_01_06_F2.jpg

Moon et al.(2017)์€ ์ฃผ๋ฉด๊ณ ์ •์•ก์˜ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„์™€ ์ž”๊ณจ์žฌ ๋ฐฐํ•ฉ๋น„๊ฐ€ ์ผ์ถ•์••์ถ•๊ฐ•๋„์— ๋ฏธ์น˜๋Š” ์˜ํ–ฅ์„ ์—ฐ๊ตฌํ•˜์˜€์œผ๋ฉฐ, ์ฃผ๋ฉด๊ณ ์ •์•ก์˜ ์ผ์ถ•์••์ถ•๊ฐ•๋„(28์ผ)๋Š” ๋ฐฐํ•ฉ๋น„์— ๋”ฐ๋ผ ์•ฝ 7~36MPa์˜ ๊ฐ’์„ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. Lee(2013)์— ์˜ํ•˜๋ฉด ์•”์„์˜ ์ข…๋ฅ˜์— ๋”ฐ๋ผ ์ผ์ถ•์••์ถ•๊ฐ•๋„๋Š” ํฐ ์ฐจ์ด๋ฅผ ๋‚˜ํƒ€๋‚ด๊ณ  ์žˆ์œผ๋ฉฐ ์‘ํšŒ์•”์ด๋‚˜ ์…ฐ์ผ์„ ์ œ์™ธํ•˜๋ฉด 51~320MPa์˜ ๋ฒ”์œ„์— ๋ถ„ํฌํ•˜๊ณ  ์žˆ๋‹ค. ์ผ๋ฐ˜์ ์œผ๋กœ ์•”์„์˜ ์ผ์ถ•์••์ถ•๊ฐ•๋„๋Š” ์ฝ˜ํฌ๋ฆฌํŠธ๋ณด๋‹ค ๋†’์€ ๊ฐ’์„ ๋ณด์ด๋ฏ€๋กœ ์•”๋ฐ˜ ์ž์ฒด์˜ ์ „๋‹จํŒŒ๊ดด๊ฐ€ ๋ฐœ์ƒํ•˜๊ธฐ ์ „์— ์ฃผ๋ฉด๊ณ ์ •์•ก์˜ ์ „๋‹จํŒŒ๊ดด๊ฐ€ ๋‚˜ํƒ€๋‚  ๊ฒƒ์œผ๋กœ ์‚ฌ๋ฃŒ๋œ๋‹ค. ์ผ๋ฐ˜ ์ฝ˜ํฌ๋ฆฌํŠธ์˜ ์ง์ ‘์ธ์žฅ๊ฐ•๋„๋Š” ์ผ์ถ•์••์ถ•๊ฐ•๋„์™€ Eq. (1)๊ณผ ๊ฐ™์€ ์ƒ๊ด€๊ด€๊ณ„๋ฅผ ๊ฐ€์ง€๊ณ  ์žˆ๋‹ค. Table 2๋Š” Moon et al.(2017)์— ์˜ํ•œ ์ฃผ๋ฉด๊ณ ์ •์•ก์˜ ์ผ์ถ•์••์ถ•๊ฐ•๋„์™€ Eq. (1)์— ์˜ํ•œ ์ง์ ‘์ธ์žฅ๊ฐ•๋„๋ฅผ ์ •๋ฆฌํ•œ ๊ฒƒ์œผ๋กœ ๊ฐ•๊ด€๊ณผ ์ฃผ๋ฉด๊ณ ์ •์•ก ์‚ฌ์ด์˜ ๋ถ€์ฐฉ๊ฐ•๋„๋ณด๋‹ค ํฐ ๊ฐ’์„ ๋‚˜ํƒ€๋‚ด๊ณ  ์žˆ์–ด ์•”๋ฐ˜๋งค์ž… ๊ฐ•๊ด€๋ง๋š์˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์€ ๊ฐ•๊ด€๊ณผ ์ฃผ๋ฉด๊ณ ์ •์•ก ์‚ฌ์ด์˜ ๋ถ€์ฐฉ๊ฐ•๋„์— ์˜ํ•ด ๊ฒฐ์ •๋œ๋‹ค.

Table 2. Strength of Grouting Materials Table_KSCE_38_01_06_T2.jpg

PICE17E.gif (1)

์—ฌ๊ธฐ์„œ, PICE18F.gif : ์ง์ ‘์ธ์žฅ๊ฐ•๋„, PICE190.gif : ์ผ์ถ•์••์ถ•๊ฐ•๋„

์•”๋ฐ˜๊ณผ ์ฃผ๋ฉด๊ณ ์ •์•ก ์‚ฌ์ด์˜ ๋ถ€์ฐฉ๊ฐ•๋„๋ฅผ ํ‰๊ฐ€ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ์•”์„์— ๊ตฌ๋ฉ์„ ๋šซ๊ณ  ์ฃผ๋ฉด๊ณ ์ •์•ก์„ ์ฑ„์šด ํ›„ ์ฃผ๋ฉด๊ณ ์ •์•ก์„ ๋ฐ€์–ด๋‚ด๋Š” ์‹คํ—˜์„ ์ˆ˜ํ–‰ํ•˜์˜€๋‹ค. ์•”์„์€ ์ œ์ฃผ๋„ ํ˜„๋ฌด์•”์œผ๋กœ ๊ธฐ๊ณต์ด ์ ์€ ๊ฒƒ(Basalt-1)๊ณผ ๊ธฐ๊ณต์ด ๋งŽ์€ ๊ฒƒ(Basalt-2)์„ ์‚ฌ์šฉํ•˜์˜€์œผ๋ฉฐ, ์ฃผ๋ฉด๊ณ ์ •์•ก์˜ ๋ฐฐํ•ฉ๋น„๋Š” Moon et al.(2017)์˜ ์—ฐ๊ตฌ๊ฒฐ๊ณผ์—์„œ ์ผ์ถ•์••์ถ•๊ฐ•๋„๊ฐ€ ๊ฐ€์žฅ ํฌ๊ฒŒ ๋‚˜ํƒ€๋‚ฌ๋˜ W06S4์™€ ๊ฐ€์žฅ ์ž‘์•˜๋˜ W12S6, ๋ชจ๋ž˜๊ฐ€ ๋ฐฐํ•ฉ๋˜์ง€ ์•Š์€ W08S0์™€ 40% ๋ฐฐํ•ฉ๋œ W08S4, ์ด 4๊ฐœ์˜ ๋ฐฐํ•ฉ๋น„๋ฅผ ์‚ฌ์šฉํ•˜์˜€๋‹ค. ์•”๋ฐ˜๊ณผ ์ฃผ๋ฉด๊ณ ์ •์•ก ์‚ฌ์ด์˜ ๋ถ€์ฐฉ๊ฐ•๋„๋Š” Table 3๊ณผ ๊ฐ™์œผ๋ฉฐ, Basalt-1์— W12S6์„ ์‚ฌ์šฉํ•œ ๊ฒฝ์šฐ, 0.95MPa๋กœ ๊ฐ€์žฅ ์ž‘์€ ๊ฐ’์„ ๋‚˜ํƒ€๋‚ด์—ˆ์œผ๋ฉฐ, Basalt-2์—์„œ๋Š” ๋ฐฐํ•ฉ๋น„์— ์ƒ๊ด€์—†์ด ์•ฝ 2.0MPa์˜ ๊ฐ’์„ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. ๋™์ผํ•œ ์ฃผ๋ฉด๊ณ ์ •์•ก ๋ฐฐํ•ฉ๋น„์—์„œ ์•”๋ฐ˜๊ณผ ์ฃผ๋ฉด๊ณ ์ •์•ก ์‚ฌ์ด์˜ ๋ถ€์ฐฉ๊ฐ•๋„๊ฐ€ ๊ฐ•๊ด€๊ณผ ์ฃผ๋ฉด๊ณ ์ •์•ก ์‚ฌ์ด์˜ ๋ถ€์ฐฉ๊ฐ•๋„๋ณด๋‹ค ํฌ๊ฒŒ ๋‚˜ํƒ€๋‚˜๋ฏ€๋กœ ์•”๋ฐ˜์— ๋งค์ž…๋œ ๊ฐ•๊ด€๋ง๋š์˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์€ ๊ฐ•๊ด€๊ณผ ์ฃผ๋ฉด๊ณ ์ •์•ก ์‚ฌ์ด์˜ ๋ถ€์ฐฉ๊ฐ•๋„์— ์˜ํ•ด ๊ฒฐ์ •๋œ๋‹ค. ์ด๋Š” Moon et al.(2014a)๊ฐ€ ์•”๋ฐ˜์— ๋งค์ž…๋œ ๊ฐ•๊ด€๋ง๋š์˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์€ ๊ฐ•๊ด€๋ง๋š๊ณผ ์ฃผ๋ฉด๊ณ ์ •์•ก ์‚ฌ์ด์—์„œ ๊ฒฐ์ •๋˜์—ˆ๋˜ ๊ฒƒ๊ณผ ๋™์ผํ•œ ๊ฒฐ๊ณผ์ด๋‹ค.

Table 3. Max. Bond Strength (Rock vs Grout) Table_KSCE_38_01_06_T3.jpg

3.2 ์‹คํ—˜์ฒด ๋ฐ ๋ณ€์ˆ˜

์ฃผ๋ฉด๊ณ ์ •์•ก์˜ ๋ฐฐํ•ฉ๋น„์— ๋”ฐ๋ฅธ ๊ฐ•๊ด€๋ง๋š์˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์„ ํ‰๊ฐ€ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ์‹คํ—˜๋ณ€์ˆ˜๋กœ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„์™€ ์ž”๊ณจ์žฌ๋น„๋ฅผ ์„ ํƒํ•˜์˜€๋‹ค. ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„๋Š” ๊ตฌ์กฐ๋ฌผ๊ธฐ์ดˆ์„ค๊ณ„๊ธฐ์ค€(KGS, 2015)์—์„œ ์ฃผ๋ฉด๊ณ ์ •์•ก์— ์ œ์‹œํ•˜๋Š” 83~100%์˜ ๋ฒ”์œ„๋ฅผ ํ™•์žฅ์‹œ์ผœ 60~120%์˜ ๋ฒ”์œ„์—์„œ 20%๊ฐ„๊ฒฉ์œผ๋กœ 4๊ฐœ์˜ ๋ณ€์ˆ˜๋ฅผ ์„ ์ •ํ•˜์˜€๋‹ค. ๋˜ํ•œ ์ž”๊ณจ์žฌ๋น„๋Š” ์‹œ๋ฉ˜ํŠธํ’€๊ณผ ์ž”๊ณจ์žฌ๊ฐ€ ๋ฐฐํ•ฉ๋œ ๋ชจ๋ฅดํƒ€๋ฅด์˜ ํŠน์„ฑ์„ ๋น„๊ต, ๊ฒ€ํ† ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ 0~60%์˜ ๋ฒ”์œ„์—์„œ 20% ๊ฐ„๊ฒฉ์œผ๋กœ 4๊ฐœ์˜ ๋ณ€์ˆ˜๋ฅผ ์‚ฌ์šฉํ•˜์˜€๋‹ค. ๋”ฐ๋ผ์„œ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„์™€ ์ž”๊ณจ์žฌ๋น„๋ฅผ ๋ณ€ํ™”์‹œ์ผœ ๋ฐฐํ•ฉํ•œ 16๊ฐœ์˜ ๊ฒฝ์šฐ์— ๋Œ€ํ•ด ์‹œํ—˜ํ•˜์˜€์œผ๋ฉฐ ์ด๋ฅผ Table 4์— ์ •๋ฆฌํ•˜์˜€๊ณ , ์‹คํ—˜์ฒด ๋ช…์€ Fig. 3์— ์ •๋ฆฌํ•œ ๊ฒƒ๊ณผ ๊ฐ™์ด ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„๋Š” W, 60~120%์˜ ๋ฒ”์œ„๋ฅผ 06~12๋กœ ์‚ฌ์šฉํ•˜์˜€์œผ๋ฉฐ, ์ž”๊ณจ์žฌ๋น„๋Š” S, 0~60%์˜ ๋ฒ”์œ„๋Š” 0~6์œผ๋กœ ํ‘œ์‹œํ•˜์˜€๋‹ค. ๊ฐ ๋ณ€์ˆ˜ ์•ˆ์—์„œ ๊ฐ๊ฐ์˜ ์‹คํ—˜์ฒด๋ฅผ ๊ตฌ๋ถ„ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ๋งˆ์ง€๋ง‰์— ๋ฒˆํ˜ธ๋ฅผ ๋ถ™์—ฌ์„œ ๊ตฌ๋ถ„ํ•˜์˜€๋‹ค.

Table 4. Experimental Parameter Table_KSCE_38_01_06_T4.jpg
Fig. 3.

Specimen I.D.

Figure_KSCE_38_01_06_F3.jpg
Fig. 4.

Experimental Specimens for Shaft Resistance

Figure_KSCE_38_01_06_F4.jpg

์‹คํ—˜์— ์‚ฌ์šฉ๋œ ๊ฐ•๊ด€์€ D50mm์ธ ๊ตฌ์กฐ์šฉ๊ฐ•๊ด€์„ ์‚ฌ์šฉํ•˜์˜€์œผ๋ฉฐ, ์ฃผ๋ฉด๊ณ ์ •์•ก์„ ์ฑ„์šฐ๊ธฐ ์œ„ํ•˜์—ฌ D100mm์˜ PE๊ด€์„ ์‚ฌ์šฉํ•˜์˜€๋‹ค. ๋ฐ”๋‹ฅ์—๋Š” 150ร—150mm์˜ ๊ฑฐํ‘ธ์ง‘์šฉ ํ•ฉํŒ์„ ์‚ฌ์šฉํ•˜์—ฌ ๋งˆ๊ฐํ•˜์˜€์œผ๋ฉฐ, ์ฃผ๋ฉด๊ณ ์ •์•ก์ด ์–‘์ƒ๋œ ํ›„ ๋ฐ”๋‹ฅ๋ฉด์„ ์ œ๊ฑฐํ•˜์—ฌ ์‹œํ—˜ํ•˜์˜€๋‹ค. ์ฃผ๋ฉด๊ณ ์ •์•ก์˜ ๋ถ€์ฐฉ๊นŠ์ด๋Š” 300mm (6D)๋กœ ์ •ํ•˜์—ฌ PE๊ด€์€ 300mm๋กœ, ๊ฐ•๊ด€์€ 500mm๋กœ ์žฌ๋‹จํ•˜์—ฌ ์‹คํ—˜์ฒด๋ฅผ ์ œ์ž‘ํ•˜์˜€๋‹ค. ์‹คํ—˜์ฒด๋Š” 16๊ฐœ์˜ ๋ณ€์ˆ˜๋ณ„๋กœ 5๊ฐœ์”ฉ ์ด 80๊ฐœ์˜ ์‹คํ—˜์ฒด๋ฅผ ์ œ์ž‘ํ•˜์˜€์œผ๋ฉฐ, Fig. 4๋Š” ์™„์„ฑ๋œ ์‹คํ—˜์ฒด๋ฅผ ๋ณด์—ฌ์ฃผ๊ณ  ์žˆ๋‹ค.

3.3 ์‚ฌ์šฉ์žฌ๋ฃŒ

์‹คํ—˜์ฒด ์ œ์ž‘์‹œ ์‹œ๋ฉ˜ํŠธ๋Š” ๊ตญ๋‚ด D์‚ฌ์—์„œ ์ œ์กฐํ•œ ํฌํ‹€๋žœ๋“œ ๋ณดํ†ต์‹œ๋ฉ˜ํŠธ(Type I)๋ฅผ ์‚ฌ์šฉํ•˜์˜€์œผ๋ฉฐ, ์ž”๊ณจ์žฌ๋Š” ์„œํ•ด ์—ฐ์•ˆ์—์„œ ์ฑ„์ทจํ•˜์—ฌ ์„ธ์ฒ™๋œ ๋ฐ”๋‹ค๋ชจ๋ž˜๋ฅผ ์‚ฌ์šฉํ•˜์˜€๋‹ค. ๋ชจ๋ž˜๋Š” ๋ฐฐํ•ฉ ์ „์— 100ยฐC์ด์ƒ์—์„œ 24์‹œ๊ฐ„ ์ด์ƒ ์™„์ „ ๊ฑด์กฐ์‹œ์ผฐ์œผ๋ฉฐ, ์ž…๋„๋ถ„ํฌ๋Š” Fig. 5์— ๋‚˜ํƒ€๋‚ธ ๊ฒƒ๊ณผ ๊ฐ™๋‹ค. ๋ณธ ์—ฐ๊ตฌ์— ์‚ฌ์šฉ๋œ ๋ชจ๋ž˜์˜ ๋ฌผ๋ฆฌ์  ํŠน์„ฑ์€ Table 5์— ์ •๋ฆฌํ•˜์˜€์œผ๋ฉฐ, ๋น„์ค‘์€ 2.64, ๊ฑด์กฐ๋‹จ์œ„์ค‘๋Ÿ‰์€ 15.78PICE1A1.gif์ด๋‹ค. ์ด ๋ชจ๋ž˜๋Š” ํ† ์งˆ๋ถ„๋ฅ˜๊ธฐ์ค€์ธ ํ†ต์ผ๋ถ„๋ฅ˜๋ฒ•(USCS)์— ์˜ํ•˜์—ฌ ๋ถ„๋ฅ˜ํ•˜๋ฉด SP๋กœ ๋ถ„๋ฅ˜๋œ๋‹ค.

Fig. 5.

Particle Size Distribution Curve of Sand

Figure_KSCE_38_01_06_F5.jpg
Table 5. Physical Properties of Sand Table_KSCE_38_01_06_T5.jpg

3.4 ์‹คํ—˜๋ฐฉ๋ฒ• ๋ฐ ์žฅ์น˜

์‹คํ—˜๋ฐฉ๋ฒ•์€ ๋ง๋š์˜ ์ •์žฌํ•˜์‹œํ—˜๋ฐฉ๋ฒ•(KS F 2445)์„ ์ฐธ์กฐํ•˜์˜€์œผ๋ฉฐ, ๋ณธ ์‹œํ—˜์—์„œ๋Š” ๋ง๋š์˜ ์ตœ๋Œ€ ๋ถ€์ฐฉ๋ ฅ์„ ์ธก์ •ํ•  ๋ฟ๋งŒ ์•„๋‹ˆ๋ผ ๊ทธ ์ดํ›„์˜ ์ฃผ๋ฉด๋งˆ์ฐฐ๊ฑฐ๋™์— ๋Œ€ํ•ด์„œ๋„ ํ‰๊ฐ€ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ๋ณ€์œ„์ œ์–ด๋กœ, ์žฌํ•˜์†๋„๋ฅผ 1.0mm/min๋กœ ์‹คํ—˜ํ•˜์˜€๋‹ค. ์‹คํ—˜์€ ์ตœ๋Œ€๋ถ€์ฐฉ๋ ฅ ์ดํ›„ ์ด ๋ณ€์œ„๊ฐ€ 20mm๋˜์—ˆ์„ ๋•Œ ์ข…๋ฃŒํ•˜์—ฌ ์ฃผ๋ฉด๊ฑฐ๋™์„ ํ‰๊ฐ€ํ•˜์˜€๋‹ค. ๋ณธ ์‹คํ—˜์—์„œ๋Š” ๋ชจํ˜• ๋ง๋š ๋‘๋ถ€์— ์ž‘์šฉํ•˜๋Š” ํ•˜์ค‘์„ ๊ตญ๋‚ด C์‚ฌ์—์„œ ์ œ์ž‘ํ•œ ๋กœ๋“œ์…€(CLS-50t)๋กœ ์ธก์ •ํ•˜์˜€์œผ๋ฉฐ, ๋‘๋ถ€์˜ ๋ณ€์œ„๋ฅผ 2๊ฐœ์˜ LVDT CDP-50, CDP-25)๋ฅผ ์‚ฌ์šฉํ•˜์—ฌ ์ธก์ •ํ•˜์˜€๋‹ค. Fig. 6์€ ์‹คํ—˜์— ์‚ฌ์šฉ๋œ ์žฅ๋น„์™€ ์‹คํ—˜์ฒด๋ฅผ ์„ค์น˜ํ•œ ๋ชจ์Šต์„ ๋‚˜ํƒ€๋‚ด๊ณ  ์žˆ๋‹ค.

Fig. 6.

Test Setup

Figure_KSCE_38_01_06_F6.jpg

4. ์‹คํ—˜๊ฒฐ๊ณผ ๋ฐ ๊ณ ์ฐฐ

4.1 ๋งค์ž…๋ง๋š์˜ ๋ถ€์ฐฉ๋ฉด์ 

์ผ๋ฐ˜์ ์ธ ์ฝ˜ํฌ๋ฆฌํŠธ ๋ฐฐํ•ฉ์—์„œ๋Š” ์™„์ „ํ•œ ์ˆ˜ํ™”์ž‘์šฉ์„ ์œ„ํ•ด ์ค‘๋Ÿ‰๋น„๋กœ ์•ฝ 25%์˜ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„๊ฐ€ ์†Œ์š”๋˜๊ณ , ์œ ๋™์„ฑ์„ ํ™•๋ณดํ•˜๊ธฐ ์œ„ํ•ด 35~40%์˜ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„๋ฅผ ์‚ฌ์šฉํ•˜๊ฒŒ ๋œ๋‹ค(Min, 2016). ๋งค์ž…๋ง๋š์˜ ์ฃผ๋ฉด๊ณ ์ •์•ก์œผ๋กœ ์‚ฌ์šฉ๋˜๋Š” ์‹œ๋ฉ˜ํŠธ ํ’€์€ ์ผ๋ฐ˜์ ์ธ ์ฝ˜ํฌ๋ฆฌํŠธ์— ์‚ฌ์šฉ๋˜๋Š” ์‹œ๋ฉ˜ํŠธ ํ’€์˜ 2๋ฐฐ ์ด์ƒ์˜ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„๋ฅผ ์‚ฌ์šฉํ•˜์—ฌ ๋ฌผ์˜ ์ž”์—ฌ๋Ÿ‰์ด ๋งค์šฐ ๋งŽ์•„ ์žฌ๋ฃŒ๋ถ„๋ฆฌ๊ฐ€ ๋ฐœ์ƒํ•˜์˜€์œผ๋ฉฐ, ์ž‰์—ฌ์ˆ˜์˜ ์ฆ๋ฐœ๋กœ ์‹ค์ œ ๋ถ€์ฐฉ๋ฉด์ ์ด ๊ฐ์†Œํ•˜์˜€๋‹ค. ๋งค์ž…๋ง๋š์˜ ์‹ค๋ถ€์ฐฉ๋ฉด์ ์„ ๊ณ„์‚ฐํ•˜๊ธฐ์œ„ํ•ด ์‹คํ—˜์ฒด ์ œ์ž‘๊ณผ์ •์—์„œ ๋‚˜ํƒ€๋‚œ ๋ธ”๋ฆฌ๋”ฉ, ๊ฑด์กฐ์ˆ˜์ถ•์œผ๋กœ ์ธํ•œ ์ฃผ๋ฉด๊ณ ์ •์•ก์ด ๊ฐ์†Œํ•œ ๊นŠ์ด๋ฅผ ์ธก์ •ํ•˜์˜€๋‹ค. Fig. 7์— ๋‚˜ํƒ€๋‚ธ ๊ฒƒ๊ณผ ๊ฐ™์ด ์ฃผ๋ฉด๊ณ ์ •์•ก์„ PE๊ด€์˜ 300mm ๋†’์ด์— ๋งž๊ฒŒ ํƒ€์„คํ•˜์˜€์œผ๋ฉฐ, ๋ชจ๋ž˜์™€ ์‹œ๋ฉ˜ํŠธ๊ฐ€ ํ˜ผํ•ฉ๋˜์–ด ๊ฐ€๋ผ์•‰๊ณ (PICE1B1.gif) ์ž”์—ฌ์ˆ˜๊ฐ€ ๊ณ ์ด๊ฒŒ ๋œ๋‹ค. ์ž”์—ฌ์ˆ˜์— ๋ถ€์œ ํ•˜๊ณ  ์žˆ๋˜ ์‹œ๋ฉ˜ํŠธ์™€ ๋ชจ๋ž˜์˜ ๋ฏธ์„ธ์ž…์ž๋“ค์ด ์‹œ๊ฐ„ ์ฐจ์ด๋ฅผ ๋‘๊ณ  ๊ฐ€๋ผ์•‰์œผ๋ฏ€๋กœ ๋ชจ๋ฅดํƒ€๋ฅด์ธต(PICE1D2.gif) ์œ„์— 10~14mm ๋‘๊ป˜์˜ ์‹œ๋ฉ˜ํŠธ์ธต(PICE1D3.gif)์„ ํ˜•์„ฑํ•˜์˜€๋‹ค(Fig. 8). ์‹คํ—˜์ฒด์˜ ๋ถ€์ฐฉ๋ฉด์ ์€ Fig. 7์— ๋‚˜ํƒ€๋‚ธ ๊ฒƒ๊ณผ ๊ฐ™์ด ๋ถ€์ฐฉ๊ธธ์ด(PICE1E3.gif)์— ๊ฐ•๊ด€์˜ ๋‘˜๋ ˆ๋ฅผ ๊ณฑํ•˜์˜€์œผ๋ฉฐ, ์‹ค๋ถ€์ฐฉ๋ฉด์ ๊ณผ ๊ณ„ํš๋ฉด์ ์˜ ๋น„๋ฅผ ๋ถ€์ฐฉ๋ฉด์ ์˜ ์ž”์—ฌ์œจ๋กœ ์ •ํ•˜์˜€๋‹ค.

Fig. 7.

Bond Length

Figure_KSCE_38_01_06_F7.jpg
Fig. 8.

Longitudinal Section (W08S6)

Figure_KSCE_38_01_06_F8.jpg
Fig. 9.

Effect of W/C Ratio on Bond Area

Figure_KSCE_38_01_06_F9.jpg

Figs. 9 and 10์€ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„์™€ ์ž”๊ณจ์žฌ ๋ฐฐํ•ฉ๋น„์— ๋”ฐ๋ฅธ ๋ถ€์ฐฉ๋ฉด์ ์˜ ์ž”์—ฌ์œจ์„ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์ด๋‹ค. Fig. 9๋ฅผ ๋ณด๋ฉด ์˜ˆ์ƒํ•œ ๋ฐ”์™€ ๊ฐ™์ด ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„๊ฐ€ ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ๋ถ€์ฐฉ๋ฉด์ ์˜ ์ž”์—ฌ์œจ์€ ์„ ํ˜•์ ์œผ๋กœ ๊ฐ์†Œํ•˜๊ณ  ์žˆ๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ ์ž”๊ณจ์žฌ ๋ฐฐํ•ฉ๋น„๊ฐ€ ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ๊ธฐ์šธ๊ธฐ ๊ฐ’์ด ๊ฐ์†Œํ•˜์—ฌ ๊ฐ์†Œํญ์ด ๋‘”ํ™”๋˜๊ณ  ์žˆ์–ด ์ž”๊ณจ์žฌ ๋ฐฐํ•ฉ์ด ์‹ค๋ถ€์ฐฉ๋ฉด์ ์˜ ๊ฐ์†Œ๋ฅผ ์™„ํ™”ํ•˜๋Š” ์—ญํ• ์„ ํ•˜๊ณ  ์žˆ์Œ์ด ํ™•์ธ๋œ๋‹ค. Fig. 10์€ ์ž”๊ณจ์žฌ๋น„์— ๋Œ€ํ•œ ๋ถ€์ฐฉ๋ฉด์ ์˜ ์ž”์—ฌ์œจ์„ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์œผ๋กœ, ์•ž์—์„œ ์–ธ๊ธ‰ํ•œ ๋ฐ”์™€ ๊ฐ™์ด ์ž”๊ณจ์žฌ๋น„๊ฐ€ ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ๋ถ€์ฐฉ๋ฉด์ ์˜ ์ž”์—ฌ์œจ์€ ์ฆ๊ฐ€ํ•˜๊ณ  ์žˆ๋‹ค. ๋˜ํ•œ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„๊ฐ€ ์ž‘์„์ˆ˜๋ก ์ž”์—ฌ์œจ์ด ํฐ ๊ฐ’์„ ๋‚˜ํƒ€๋‚ด๊ณ  ์žˆ์œผ๋‚˜, ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„๊ฐ€ ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ์ž”๊ณจ์žฌ ๋ฐฐํ•ฉ๋น„์˜ ๋ณ€ํ™”์— ์˜ํ•œ ๋ถ€์ฐฉ๋ฉด์ ์˜ ๋ณ€ํ™”ํญ์ด ์ปค์ง€๊ณ  ์žˆ๋‹ค. ์ด๋Š” ์ž”๊ณจ์žฌ๊ฐ€ ๋ฐฐํ•ฉ๋จ์— ๋”ฐ๋ผ ์‹œ๋ฉ˜ํŠธ ํ’€์˜ ๋ฐฐํ•ฉ์–‘์ด ์ƒ๋Œ€์ ์œผ๋กœ ๊ฐ์†Œํ•˜๋ฏ€๋กœ ๋ฌผ์˜ ์–‘์ด ์ค„์–ด๋“ค๊ธฐ ๋•Œ๋ฌธ์— ์ด๋Ÿฌํ•œ ๊ฒฝํ–ฅ์ด ๋‚˜ํƒ€๋‚˜๋Š” ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

Fig. 10.

Effect of Sand Proportion on Bond Area

Figure_KSCE_38_01_06_F10.jpg

4.2 ๋งค์ž…๋ง๋š์˜ ์ฃผ๋ฉด์ง€์ง€๊ฑฐ๋™

์ฃผ๋ฉด๊ณ ์ •์•ก์˜ ๋ฐฐํ•ฉ๋น„์— ๋”ฐ๋ผ ์‹ค๋ถ€์ฐฉ๋ฉด์ ์— ์ฐจ์ด๋ฅผ ๋‚˜ํƒ€๋‚ด๋ฏ€๋กœ ์‹คํ—˜๋ฐ์ดํ„ฐ๋Š” ์‹ค๋ถ€์ฐฉ๋ฉด์ ์„ ๊ธฐ์ค€์œผ๋กœ ์ •๋ฆฌํ•˜์˜€๋‹ค. Fig. 11์€ ๋ชจํ˜•๋ง๋š์˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ๊ณผ ๋ณ€์œ„์˜ ๊ด€๊ณ„๋ฅผ ๊ฐ ๋ณ€์ˆ˜๋ณ„๋กœ ๋Œ€ํ‘œ๋˜๋Š” ์‹คํ—˜์ฒด๋ฅผ ์„ ์ •ํ•˜์—ฌ ๋„์‹ํ•œ ๊ฒƒ์œผ๋กœ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„๋กœ ๊ตฌ๋ถ„ํ•˜์—ฌ ๊ทธ๋ž˜ํ”„๋ฅผ ์ •๋ฆฌํ•˜์˜€์œผ๋ฉฐ, ๊ฐ ๊ทธ๋ž˜ํ”„ ๋‚ด์—์„œ๋Š” ์ž”๊ณจ์žฌ ๋ฐฐํ•ฉ๋น„์— ๋”ฐ๋ผ ๋„์‹ํ•˜์˜€๋‹ค. Fig. 11์— ๋‚˜ํƒ€๋‚ธ ๋ฐ”์™€ ๊ฐ™์ด ์ดˆ๊ธฐ์—๋Š” ์ฃผ๋ฉด์ง€์ง€๋ ฅ๊ณผ ๋ณ€์œ„๊ฐ€ ์„ ํ˜•์ ์œผ๋กœ ๋น„๋ก€ํ•˜์—ฌ ์ฆ๊ฐ€ํ•˜๋‹ค๊ฐ€ 0.5~1.5mm์˜ ๋ณ€์œ„์—์„œ ์ตœ๋Œ“๊ฐ’์„ ๋ณด์ด๊ณ , ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ ์ดํ›„์—๋Š” ์ง€์ง€๋ ฅ์ด ๊ธ‰๊ฒฉํžˆ ๊ฐ์†Œํ•˜๋Š” ๊ฑฐ๋™์„ ํ•˜๊ณ  ์žˆ๋‹ค. ๋˜ํ•œ, ์ตœ๋Œ“๊ฐ’ ์ดํ›„์—๋Š” ์ง€์ง€๋ ฅ์— ํฐ ๋ณ€ํ™”์—†์ด ๋ณ€์œ„๋งŒ ์ฆ๊ฐ€ํ•˜๋Š” ํ˜•ํƒœ์˜ ๊ฑฐ๋™์„ ๋ชจ๋“  ์‹คํ—˜์ฒด์—์„œ ๋™์ผํ•˜๊ฒŒ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์€ ๊ฐ•๊ด€ํ‘œ๋ฉด๊ณผ ์ฃผ๋ฉด๊ณ ์ •์•ก ์‚ฌ์ด์˜ ํ™”ํ•™์  ๋ถ€์ฐฉ๋ ฅ๊ณผ ๋ฌผ๋ฆฌ์  ๋งž๋ฌผ๋ฆผ์— ์˜ํ•ด ๋‚˜ํƒ€๋‚˜๋Š” ๊ฐ’(Nezamian et al., 2002)์ด๋ฉฐ, ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ ์ดํ›„ ์ง€์ง€๋ ฅ์ด ๊ธ‰๊ฒฉํžˆ ๊ฐ์†Œํ•˜์—ฌ ๊ฑฐ์˜ ์ผ์ •ํ•œ ๊ฐ’์—์„œ ๋ณ€์œ„๋งŒ ์ฆ๊ฐ€ํ•˜๋Š” ๊ตฌ๊ฐ„์˜ ์ง€์ง€๋ ฅ์€ ๊ฐ•๊ด€ํ‘œ๋ฉด๊ณผ ์ฃผ๋ฉด๊ณ ์ •์•ก ์‚ฌ์ด์˜ ๋งˆ์ฐฐ์— ์˜ํ•ด ๋ฐœ์ƒํ•˜๋Š” ๊ฒƒ์œผ๋กœ ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์ด๋ผ ํ‘œํ˜„ํ•˜์˜€๋‹ค.

์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์— ์žˆ์–ด์„œ ์ž”๊ณจ์žฌ๋ฅผ ๋ฐฐํ•ฉํ•˜๋Š” ๊ฒƒ(20~60%)์ด ๋ฐฐํ•ฉํ•˜์ง€ ์•Š์€ ๊ฒƒ(0%)๋ณด๋‹ค ํฌ๊ฒŒ ๋‚˜ํƒ€๋‚˜๊ณ  ์žˆ๋‹ค. ๋˜ํ•œ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„์˜ ์ฆ๊ฐ€๊ฐ€ ์ž”๊ณจ์žฌ ๋ฐฐํ•ฉ์— ๋”ฐ๋ฅธ ์ง€์ง€๋ ฅ์˜ ํŽธ์ฐจ์— ์˜ํ–ฅ์„ ๋ฏธ์น˜๋Š” ๊ฒƒ์„ ํ™•์ธํ•  ์ˆ˜ ์žˆ๋Š”๋ฐ, ์ด๋Š” ์ž”๊ณจ์žฌ ๋ฐฐํ•ฉ๊ณผ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„์˜ ์ฆ๊ฐ€๊ฐ€ ์‹œ๋ฉ˜ํŠธ์˜ ์–‘์„ ์ƒ๋Œ€์ ์œผ๋กœ ๊ฐ์†Œ์‹œ์ผœ ๊ณ ์ •์•ก์˜ ๊ฒฐํ•ฉ๋ ฅ์„ ์ €ํ•˜์‹œํ‚ค๊ธฐ ๋•Œ๋ฌธ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

Fig. 11.

Shaft Resistance-Displacement Curves

Figure_KSCE_38_01_06_F11.jpg
Fig. 12.

Effect of the Proportion of Grouting Material on Maximum Shaft Resistance

Figure_KSCE_38_01_06_F12.jpg

4.3 ๋ฐฐํ•ฉ๋น„์— ๋”ฐ๋ฅธ ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ

Fig. 12๋Š” ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„์™€ ์ž”๊ณจ์žฌ ๋ฐฐํ•ฉ๋น„์— ๋”ฐ๋ฅธ ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์„ ๋„์‹ํ•œ ๊ฒƒ์œผ๋กœ ๊ฐ ๋ณ€์ˆ˜ ๋‚ด์—์„œ ๊ฐ’์˜ ํŽธ์ฐจ๊ฐ€ 300kPa์˜ ๋ฒ”์œ„๋กœ ๋‹ค์†Œ ํฌ๊ฒŒ ๋‚˜ํƒ€๋‚ฌ๋‹ค. Fig. 12(a)๋Š” ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์— ๋Œ€ํ•œ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„์˜ ์˜ํ–ฅ์„ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์œผ๋กœ ์ž”๊ณจ์žฌ๊ฐ€ ๋ฐฐํ•ฉ๋˜์ง€ ์•Š์€ ๊ฒฝ์šฐ๋Š” ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„์˜ ๋ณ€ํ™”์™€ ๋ฌด๊ด€ํ•˜๊ฒŒ ์•ฝ 350~650kPa์˜ ๋ฒ”์œ„์— ๋ถ„ํฌํ•˜๊ณ  ์žˆ์œผ๋ฉฐ, ์ž”๊ณจ์žฌ๊ฐ€ ๋ฐฐํ•ฉ๋˜๋Š” ๊ฒฝ์šฐ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„์˜ ์ฆ๊ฐ€์— ๋”ฐ๋ผ ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์ด ๊ฐ์†Œํ•˜๋Š” ๊ฒฝํ–ฅ์„ ๋ณด์ด๊ณ  ์žˆ์œผ๋ฉฐ, ์ž”๊ณจ์žฌ ๋ฐฐํ•ฉ๋น„๊ฐ€ ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ๊ฐ์†Œํญ์ด ์ฆ๊ฐ€ํ•˜๊ณ  ์žˆ๋‹ค. ์ž”๊ณจ์žฌ๊ฐ€ ๋ฐฐํ•ฉ๋˜์ง€ ์•Š์€ ๊ฒฝ์šฐ๋Š” ์•ž์—์„œ๋„ ์–ธ๊ธ‰ํ•œ ๋ฐ”์™€ ๊ฐ™์ด ์ˆ˜ํ™”์ž‘์šฉ์— ํ•„์š”ํ•œ ๋ฌผ์€ ์‹œ๋ฉ˜ํŠธ์˜ ์•ฝ 25%์ด๋ฉฐ, ๋ณธ ์‹คํ—˜์— ์‚ฌ์šฉ๋œ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„๋Š” ์ˆ˜ํ™”์ž‘์šฉ์— ๋งค์šฐ ์ถฉ๋ถ„ํ•˜๋ฏ€๋กœ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„์˜ ๋ณ€ํ™”๊ฐ€ ์‹œ๋ฉ˜ํŠธํ’€์˜ ๊ฐ•๋„ ๋ณ€ํ™”์— ํฐ ์˜ํ–ฅ์„ ๋ฏธ์น˜์ง€ ๋ชปํ•˜๋Š” ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค. ๋ฐ˜๋ฉด, ์ž”๊ณจ์žฌ๊ฐ€ ๋ฐฐํ•ฉ๋œ ๊ฒฝ์šฐ, ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„๊ฐ€ ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์ด ๊ฐ์†Œํ•˜๋Š” ๊ฒƒ์€ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„์™€ ์ž”๊ณจ์žฌ ๋ฐฐํ•ฉ๋น„์˜ ์ฆ๊ฐ€๊ฐ€ ์ž”๊ณจ์žฌ๋ฅผ ๊ฒฐํ•ฉ์‹œํ‚ค๋Š” ์‹œ๋ฉ˜ํŠธ์˜ ์–‘์„ ์ƒ๋Œ€์ ์œผ๋กœ ๊ฐ์†Œ์‹œ์ผœ ๊ณจ์žฌ์‚ฌ์ด์˜ ๊ฒฐํ•ฉ๋ ฅ์„ ์ €ํ•˜์‹œํ‚ค๊ธฐ ๋•Œ๋ฌธ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

Fig. 12(b)๋Š” ์ž”๊ณจ์žฌ ๋ฐฐํ•ฉ๋น„์— ๋”ฐ๋ฅธ ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์˜ ์˜ํ–ฅ์„ ํƒ€๋‚˜๋‚ธ ๊ฒƒ์œผ๋กœ ์ž”๊ณจ์žฌ ๋ฐฐํ•ฉ๋น„๊ฐ€ ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์€ ์ฆ๊ฐ€ํ•˜๋Š” ๊ฒฝํ–ฅ์„ ๋‚˜ํƒ€๋‚ด๊ณ  ์žˆ๋‹ค. ์ด๋Š” ์ž”๊ณจ์žฌ๊ฐ€ ๋ฐฐํ•ฉ๋œ ๊ฒฝ์šฐ ๊ฐ•๊ด€๋ง๋š์˜ ํ‘œ๋ฉด๊ณผ ์ฃผ๋ฉด๊ณ ์ •์•ก ์‚ฌ์ด์—์„œ ์‹œ๋ฉ˜ํŠธํ’€์— ์˜ํ•œ ๋ถ€์ฐฉ๋ ฅ๊ณผ ๋”๋ถˆ์–ด ๋งž๋ฌผ๋ฆผ ํšจ๊ณผ๊ฐ€ ๋ฐœ์ƒํ•˜์—ฌ ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์„ ์ฆ์ง„์‹œํ‚ค๋Š” ํšจ๊ณผ๊ฐ€ ์žˆ๋Š” ๊ฒƒ์œผ๋กœ ์‚ฌ๋ฃŒ๋œ๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„๊ฐ€ 80~120%์ธ ๊ฒฝ์šฐ, ์ž”๊ณจ์žฌ๋ฅผ 60% ๋ฐฐํ•ฉํ•˜์˜€์„ ๋•Œ, ๋ฐฐํ•ฉ๋น„๊ฐ€ 40%์ธ ๊ฒƒ๊ณผ ๋น„์Šทํ•˜๊ฑฐ๋‚˜ ๊ฐ์†Œ๋œ ๊ฐ’์„ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. ์ด๋Š” ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„๊ฐ€ ํฌ๊ณ , ์ž”๊ณจ์žฌ๋ฅผ 60%๋ฐฐํ•ฉํ•œ ๊ฒฝ์šฐ ์‹œ๋ฉ˜ํŠธ์˜ ์–‘์ด ์ƒ๋Œ€์ ์œผ๋กœ ๋ถ€์กฑํ•˜์—ฌ ์ž”๊ณจ์žฌ ์‚ฌ์ด์˜ ๊ฒฐํ•ฉ๋ ฅ์ด ์ €ํ•˜๋˜๋ฏ€๋กœ ์˜คํžˆ๋ ค ๋ถ€์ฐฉ๊ฐ•๋„๊ฐ€ ์ €ํ•˜๋˜๋Š” ๊ฒƒ์œผ๋กœ ์ถ”์ธก๋œ๋‹ค.

4.4 ๋ฐฐํ•ฉ๋น„์— ๋”ฐ๋ฅธ ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ

Fig. 13์€ ๋ฐฐํ•ฉ๋น„์— ๋”ฐ๋ฅธ ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์„ ๋„์‹ํ•œ ๊ฒƒ์œผ๋กœ ๋ณ€์ˆ˜๋ณ„๋กœ ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ๊ณผ ์œ ์‚ฌํ•œ ๊ฒฝํ–ฅ์„ฑ์„ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค.

Fig. 13(a)๋Š” ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„์— ๋”ฐ๋ฅธ ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์„ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์œผ๋กœ ์ž”๊ณจ์žฌ๋ฅผ ๋ฐฐํ•ฉํ•˜์ง€ ์•Š์€ ์‹œ๋ฉ˜ํŠธํ’€์€ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„๊ฐ€ ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์— ์˜ํ–ฅ์„ ์ฃผ์ง€ ์•Š์•˜์œผ๋ฉฐ 100~250kPa์˜ ๋ฒ”์œ„์— ๋ถ„ํฌํ•˜์˜€๋‹ค. ์ž”๊ณจ์žฌ๊ฐ€ ๋ฐฐํ•ฉ๋œ ๊ฒฝ์šฐ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„์˜ ์ฆ๊ฐ€๋Š” ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์„ ์ €ํ•˜์‹œ์ผฐ์œผ๋ฉฐ, ์ž”๊ณจ์žฌ ๋ฐฐํ•ฉ๋น„๊ฐ€ ์ฆ๊ฐ€ํ• ์ˆ˜๋ก ๊ทธ ์˜ํ–ฅ์€ ํฌ๊ฒŒ ๋‚˜ํƒ€๋‚ฌ๋‹ค. ์ด๋Š” ์ž”๊ณจ์žฌ ๋ฐฐํ•ฉ๋น„์™€ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„๊ฐ€ ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ์ž”๊ณจ์žฌ๋ฅผ ๊ฒฐํ•ฉ์‹œํ‚ค๋Š” ์‹œ๋ฉ˜ํŠธ์–‘์ด ์ƒ๋Œ€์ ์œผ๋กœ ๊ฐ์†Œํ•˜๊ธฐ ๋•Œ๋ฌธ์œผ๋กœ ์—ฌ๊ฒจ์ง„๋‹ค.

Fig. 13.

Effect of the Proportion of Grouting Material on Residual Shaft Resistance

Figure_KSCE_38_01_06_F13.jpg

Fig. 13(b)๋Š” ์ž”๊ณจ์žฌ ๋ฐฐํ•ฉ๋น„๊ฐ€ ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์— ๋ฏธ์น˜๋Š” ์˜ํ–ฅ์„ ๋„์‹ํ•œ ๊ฒƒ์œผ๋กœ, ๋ถ€์ฐฉ๊ฐ•๋„์™€ ์œ ์‚ฌํ•œ ๊ฒฝํ–ฅ์„ ๋‚˜ํƒ€๋‚ด๊ณ  ์žˆ๋‹ค. ์ž”๊ณจ์žฌ์˜ ์ฆ๊ฐ€๋Š” ๊ฐ•๊ด€ํ‘œ๋ฉด๊ณผ ์ฃผ๋ฉด๊ณ ์ •์•ก ์‚ฌ์ด์— ๋ถ€์ฐฉ๋˜๋Š” ์ž…์ž์˜ ์–‘์„ ์ฆ๊ฐ€์‹œํ‚ค๋ฏ€๋กœ ๋‘ ์ ‘์ด‰๋ฉด์ด ๋ฏธ๋„๋Ÿฌ์งˆ ๋•Œ ์ ‘์ด‰๋ฉด ์‚ฌ์ด์˜ ๋ฌผ๋ฆฌ์  ๋งž๋ฌผ๋ฆผ ํšจ๊ณผ์— ์˜ํ•ด ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์ด ์ฆ๊ฐ€๋˜๋Š” ๊ฒƒ์œผ๋กœ ์‚ฌ๋ฃŒ๋œ๋‹ค. ๋‹ค๋งŒ, ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„๊ฐ€ 80%์ด์ƒ์ด๊ณ , ์ž”๊ณจ์žฌ ๋ฐฐํ•ฉ๋น„๊ฐ€ 60%์ธ ๊ฒฝ์šฐ์—๋Š” ๊ฐ’์ด ๊ฐ์†Œํ•˜๋Š” ๊ฒฝํ–ฅ์„ ๋ณด์ด๊ณ  ์žˆ๋Š”๋ฐ, ์ด๋Š” ์ž”๊ณจ์žฌ์˜ ์ฆ๊ฐ€๋กœ ์ธํ•˜์—ฌ ์ƒ๋Œ€์ ์œผ๋กœ ์‹œ๋ฉ˜ํŠธ์˜ ์–‘์ด ๊ฐ์†Œํ•˜๋ฏ€๋กœ ์ž”๊ณจ์žฌ๋ฅผ ๊ฒฐํ•ฉ์‹œํ‚ค๋Š” ๊ฒฐํ•ฉ๋ ฅ์ด ์ €ํ•˜๋˜์–ด ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์ด ์ €ํ•˜๋˜๋Š” ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

4.5 ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ vs. ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ

Fig. 14๋Š” ๊ฐ ๋ณ€์ˆ˜๋ณ„ ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ๊ณผ ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์˜ ํ‰๊ท ๊ฐ’์„ ๋ฐฐํ•ฉ๋น„์— ๋”ฐ๋ผ ๊ทธ๋ฆฐ ๊ฒƒ์ด๋‹ค. ์•ž์„œ ์–ธ๊ธ‰ํ•œ ๋ฐ”์™€ ๊ฐ™์ด ์ž”๊ณจ์žฌ๋ฅผ ๋ฐฐํ•ฉํ•˜๋Š” ๊ฒƒ์ด ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ๊ณผ ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์„ ์ฆ์ง„์‹œํ‚ค๋Š” ํšจ๊ณผ๊ฐ€ ์žˆ์Œ์„ ๊ทธ๋ฆผ์„ ํ†ตํ•ด์„œ ํ™•์ธํ•  ์ˆ˜ ์žˆ๋‹ค. ์ž”๊ณจ์žฌ๊ฐ€ ์—†๋Š” ๊ฒฝ์šฐ ์ตœ๋Œ€๋ถ€์ฐฉ๋ ฅ๊ณผ ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์€ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„์— ์ƒ๊ด€์—†์ด ๊ฐ๊ฐ ์•ฝ 540~560kPa, ์•ฝ 170~200kPa์˜ ๊ฐ’์„ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. ์ž”๊ณจ์žฌ๋น„๊ฐ€ 40%์ธ ๊ฒฝ์šฐ์—๋Š” ์ตœ๋Œ€๋ถ€์ฐฉ๋ ฅ๊ณผ ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์ด ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„์— ๋”ฐ๋ผ ๊ฐ๊ฐ ์•ฝ 770~870kPa, ์•ฝ 180~250kPa์˜ ๊ฐ’์„ ๋‚˜ํƒ€๋‚ด๊ณ  ์žˆ๋‹ค. ๋‹ค๋งŒ ์ž”๊ณจ์žฌ๋ฅผ 20% ๋ฐฐํ•ฉํ•œ ๊ฒฝ์šฐ, ๋ฐฐํ•ฉํ•˜์ง€ ์•Š์€ ๊ฒƒ๋ณด๋‹ค ์„ฑ๋Šฅ์ด ํฌ๊ฒŒ ํ–ฅ์ƒ๋˜์ง€ ์•Š์•˜์œผ๋‚˜, 40% ๋ฐฐํ•ฉํ•˜์˜€์„ ๋•Œ ์ตœ๋Œ€๋ถ€์ฐฉ๋ ฅ์€ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„์— ๋”ฐ๋ผ ์•ฝ 40~55% ์ฆ๊ฐ€๋˜์—ˆ๊ณ , ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์€ ์•ฝ 10~40% ์ฆ๊ฐ€๋˜์—ˆ๋‹ค. ์ž”๊ณจ์žฌ 60%์˜ ๋ฐฐํ•ฉ์€ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„๊ฐ€ 80% ์ด์ƒ์—์„œ ์„ฑ๋Šฅ์„ ์ €ํ•˜์‹œํ‚ค๊ธฐ ๋•Œ๋ฌธ์— ๋ณธ ์‹คํ—˜์—์„œ ๊ฒ€์ฆํ•œ ๋ฐฐํ•ฉ์—์„œ๋Š” ์ž”๊ณจ์žฌ๋ฅผ 40% ์ •๋„ ๋ฐฐํ•ฉํ•˜๋Š” ๊ฒƒ์ด ๊ฐ€์žฅ ์šฐ์ˆ˜ํ•œ ์„ฑ๋Šฅ์„ ๋‚˜ํƒ€๋‚ด๊ณ  ์žˆ๋‹ค. ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„์— ์žˆ์–ด์„œ๋Š” 80~100%์˜ ๊ฐ’์„ ์‚ฌ์šฉํ•  ๋•Œ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์ด ๊ฐ€์žฅ ํฌ๊ฒŒ ๋‚˜ํƒ€๋‚ฌ๋‹ค.

Fig. 14.

Average Value of Maximum and Residual Shaft Resistance

Figure_KSCE_38_01_06_F14.jpg

Fig. 15๋Š” ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ๊ณผ ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์˜ ์ƒ๊ด€์„ฑ์„ ๋ถ„์„ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ์‚ฌ์šฉ๋œ ๋ชจ๋“  ์‹œํ—˜์ฒด์˜ ๊ฒฐ๊ณผ๋ฅผ ๋„์‹ํ•œ ๊ฒƒ์œผ๋กœ ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์ด ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ๋„ ์„ ํ˜•์ ์œผ๋กœ ์ฆ๊ฐ€ํ•˜๋Š” ์–‘์ƒ์„ ๋‚˜ํƒ€๋‚ด๊ณ  ์žˆ๋‹ค. ์‹คํ—˜๋ฐ์ดํ„ฐ๋ฅผ ํ†ตํ•œ ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ๊ณผ ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ ์‚ฌ์ด์˜ ์ƒ๊ด€์‹์€ Eq. (2)๊ณผ ๊ฐ™์œผ๋ฉฐ, ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์€ ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์˜ ์•ฝ 30%์˜ ๊ฐ’์„ ๋ณด์ด๋Š” ๊ฒƒ์œผ๋กœ ๋ถ„์„๋˜์—ˆ๋‹ค. ์ƒ๊ด€์‹์˜ ๊ฒฐ์ •๊ณ„์ˆ˜(PICE1E4.gif)๋Š” 0.47๋กœ ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ๊ณผ ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ ์‚ฌ์ด์— ์ƒ๊ด€์„ฑ์€ ์žˆ์–ด ๋ณด์ด๋‚˜ ๊ทธ ํŽธ์ฐจ๊ฐ€ ํฌ๊ฒŒ ๋‚˜ํƒ€๋‚ฌ๋‹ค.

Fig. 15.

Relationship of Max. and Residual Shaft Resistance

Figure_KSCE_38_01_06_F15.jpg

PICE1F5.gif (2)

์—ฌ๊ธฐ์„œ, PICE1F6.gif : ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ, PICE206.gif : ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ

5. ๊ฒฐ ๋ก 

์ฃผ๋ฉด๊ณ ์ •์•ก์˜ ๋ฐฐํ•ฉ๋น„์— ๋”ฐ๋ฅธ ์•”๋ฐ˜๋งค์ž… ๊ฐ•๊ด€๋ง๋š์˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์„ ํ‰๊ฐ€ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„์™€ ์ž”๊ณจ์žฌ๋น„๋ฅผ ๋ณ€ํ™”์‹œ์ผœ ๋ชจํ˜•์‹คํ—˜์„ ์ˆ˜ํ–‰ํ•˜์—ฌ ๊ทธ ๊ฒฐ๊ณผ๋ฅผ ๋ถ„์„ํ•œ ๊ฒฐ๋ก ์€ ๋‹ค์Œ๊ณผ ๊ฐ™๋‹ค.

(1)๋งค์ž…๋ง๋š์˜ ์ฃผ๋ฉด๊ณ ์ •์•ก์€ ํƒ€์„ค ํ›„ ์ž…์ž์˜ ์ค‘๋Ÿ‰ ์ฐจ์ด๋กœ ์ธํ•ด ๊ฐ€์žฅ ๋จผ์ € ๋ชจ๋ž˜์™€ ์‹œ๋ฉ˜ํŠธ๊ฐ€ ํ˜ผํ•ฉ๋œ ํ˜•ํƒœ๋กœ ์นจ๊ฐ•ํ•˜์—ฌ ๋ชจ๋ฅดํƒ€๋ฅด ์ธต์„ ํ˜•์„ฑํ•˜๊ณ , ์ž‰์—ฌ์ˆ˜์— ๋ถ€์œ ํ•˜๋˜ ์‹œ๋ฉ˜ํŠธ์™€ ๋ชจ๋ž˜์˜ ๋ฏธ์„ธ์ž…์ž๊ฐ€ 2์ฐจ๋กœ ์นจ๊ฐ•ํ•˜์—ฌ ์‹œ๋ฉ˜ํŠธ์ธต์„ ํ˜•์„ฑํ•˜๊ณ  ๊ทธ ์œ„์— ์ž‰์—ฌ์ˆ˜๊ฐ€ ๋ถ„ํฌํ•œ๋‹ค. ์ž…์ž ์นจ๊ฐ• ํ›„ ์ž‰์—ฌ์ˆ˜๋Š” ๋ชจ๋‘ ์ฆ๋ฐœํ•˜๋ฏ€๋กœ ๋ฐฐํ•ฉ๋น„์— ๋”ฐ๋ผ ์ž…์ž์˜ ์–‘ ์ฐจ์ด๋กœ ์ธํ•ด ์‹ค์ œ ๋ถ€์ฐฉ๊ธธ์ด๊ฐ€ ๋ณ€์ˆ˜๋ณ„๋กœ ์ƒ์ดํ•˜๋‹ค.

(2)๋งค์ž…๋ง๋š ๋ถ€์ฐฉ๋ฉด์ ์€ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„๊ฐ€ ๊ฐ์†Œํ•˜๊ณ  ์ž”๊ณจ์žฌ ๋ฐฐํ•ฉ๋น„๊ฐ€ ์ฆ๊ฐ€ํ• ์ˆ˜๋ก ํฌ๊ฒŒ ๋‚˜ํƒ€๋‚˜๋ฉฐ, ๋ถ€์ฐฉ๋ฉด์ ์˜ ์ž”์—ฌ์œจ์—๋Š” ์ž”๊ณจ์žฌ ๋ฐฐํ•ฉ๋น„๋ณด๋‹ค ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„์˜ ์˜ํ–ฅ์ด ๋” ํฌ๊ฒŒ ๋‚˜ํƒ€๋‚œ๋‹ค. ์ง€ํ•˜์ˆ˜์œ„๊ฐ€ ์กด์žฌํ•˜๋Š” ํ˜„์žฅ์—์„œ๋Š” ์„ค๊ณ„๋œ ์ฃผ๋ฉด๊ณ ์ •์•ก์˜ ๋ฐฐํ•ฉ๋น„์™€ ๋‹ฌ๋ฆฌ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„๊ฐ€ ๋ณ€ํ™”๋  ๊ฐ€๋Šฅ์„ฑ์ด ์žˆ์–ด ๋ถ€์ฐฉ๋ฉด์  ์‚ฐ์ •์‹œ ์ถฉ๋ถ„ํ•œ ๊ณ ๋ ค๊ฐ€ ์š”๊ตฌ๋œ๋‹ค.

(3)๋งค์ž…๋ง๋š์˜ ์ฃผ๋ฉด์ง€์ง€๊ฑฐ๋™์€ ์ดˆ๊ธฐ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์ด ๊ฑฐ์˜ ์„ ํ˜•์ ์œผ๋กœ ๋ณ€์œ„์˜ ์ฆ๊ฐ€์— ๋”ฐ๋ผ ์ฆ๊ฐ€ํ•˜๋‹ค ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์— ๋„๋‹ฌํ•˜๋ฉด ๊ฐ•๊ด€ํ‘œ๋ฉด๊ณผ ์ฃผ๋ฉด๊ณ ์ •์žฌ ์‚ฌ์ด์˜ ๋ถ€์ฐฉ๋ ฅ์ด ์ƒ์‹ค๋˜์–ด ์ง€์ง€๋ ฅ์ด ๊ธ‰๊ฒฉํžˆ ๋–จ์–ด์ง„ ํ›„ ๊ฑฐ์˜ ์ผ์ •ํ•œ ์ง€์ง€๋ ฅ์—์„œ ๋ณ€์œ„๋งŒ ์ฆ๊ฐ€ํ•˜๋Š” ๋งˆ์ฐฐ๊ฑฐ๋™์„ ํ•œ๋‹ค.

(4)์ž”๊ณจ์žฌ๊ฐ€ ๋ฐฐํ•ฉ๋˜์ง€ ์•Š์€ ์‹œ๋ฉ˜ํŠธํ’€์˜ ๊ฒฝ์šฐ๋Š” ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ๊ณผ ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์€ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„์˜ ๋ณ€ํ™”์— ๊ด€๊ณ„์—†์ด ๊ฑฐ์˜ ์ผ์ •ํ•œ ๊ฐ’์„ ๋‚˜ํƒ€๋‚ด๊ณ , ์ž”๊ณจ์žฌ๊ฐ€ ๋ฐฐํ•ฉ๋˜๋Š” ๊ฒฝ์šฐ๋Š” ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„๊ฐ€ ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ๊ฐ์†Œํ•˜๋Š” ๊ฒฝํ–ฅ์„ ๋‚˜ํƒ€๋‚ธ๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ ์ž”๊ณจ์žฌ ๋ฐฐํ•ฉ๋น„๊ฐ€ 60%์ด๊ณ , ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„๊ฐ€ 80% ์ด์ƒ์ธ ๊ฒฝ์šฐ ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ๊ณผ ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์€ ์˜คํžˆ๋ ค ๊ฐ์†Œํ•˜๋Š”๋ฐ, ์ด๋Š” ์ƒ๋Œ€์ ์œผ๋กœ ์‹œ๋ฉ˜ํŠธ์–‘์ด ๊ฐ์†Œํ•˜์—ฌ ๊ณจ์žฌ์‚ฌ์ด์˜ ๊ฒฐํ•ฉ๋ ฅ์ด ์ €ํ•˜๋˜๊ธฐ ๋•Œ๋ฌธ์œผ๋กœ ํ•ด์„๋œ๋‹ค.

(5)์ž”๊ณจ์žฌ๊ฐ€ ์—†๋Š” ๊ฒฝ์šฐ ์ตœ๋Œ€๋ถ€์ฐฉ๋ ฅ๊ณผ ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์€ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„์— ์ƒ๊ด€์—†์ด ๊ฐ๊ฐ ์•ฝ 540~560kPa, ์•ฝ 170~200kPa์˜ ๊ฐ’์„ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. ์ž”๊ณจ์žฌ๋น„๊ฐ€ 40%์ธ ๊ฒฝ์šฐ์—๋Š” ์ตœ๋Œ€๋ถ€์ฐฉ๋ ฅ๊ณผ ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์ด ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„์— ๋”ฐ๋ผ ๊ฐ๊ฐ ์•ฝ 770~870kPa, ์•ฝ 180~250kPa์˜ ๊ฐ’์„ ๋‚˜ํƒ€๋‚ด๊ณ  ์žˆ๋‹ค. ์ฆ‰, ์ตœ๋Œ€๋ถ€์ฐฉ๋ ฅ์€ ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„์— ๋”ฐ๋ผ ์•ฝ 40~55% ์ฆ๊ฐ€๋˜์—ˆ๊ณ , ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์€ ์•ฝ 10~40% ์ฆ๊ฐ€๋˜์—ˆ๋‹ค. ๋ณธ ์‹คํ—˜์—์„œ ๊ฒ€์ฆํ•œ ๋ฐฐํ•ฉ์—์„œ๋Š” ์ž”๊ณจ์žฌ๋น„๋ฅผ 40% ์ •๋„, ๋ฌผ/์‹œ๋ฉ˜ํŠธ๋น„๋ฅผ 80~100% ์‚ฌ์šฉํ•  ๋•Œ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์ด ๊ฐ€์žฅ ํฌ๊ฒŒ ๋‚˜ํƒ€๋‚ฌ๋‹ค.

(6)๋ณธ ์‹คํ—˜์—์„œ ์–ป์€ ๋ฐ์ดํ„ฐ๋ฅผ ๊ฐ€์ง€๊ณ  ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ๊ณผ ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์˜ ๊ด€๊ณ„๋ฅผ ํšŒ๊ท€๋ถ„์„ ํ•œ ๊ฒฐ๊ณผ, ์ž”๋ฅ˜ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์€ ์ตœ๋Œ€ ์ฃผ๋ฉด์ง€์ง€๋ ฅ์˜ ์•ฝ 30%์˜ ๊ฐ’์„ ๋ณด์˜€๋‹ค.

Acknowledgements

์ด ๋…ผ๋ฌธ์€ 2016๋…„๋„ ์ œ์ฃผ๋Œ€ํ•™๊ต ๊ต์›์„ฑ๊ณผ์ง€์›์‚ฌ์—…์— ์˜ํ•˜์—ฌ ์—ฐ๊ตฌ๋˜์—ˆ์Œ.

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