This paper is a case study to demonstrate the applicability of a new horizontal jet grouting construction technology to from a ring of improved ground around the tunnel periphery which will guarantee the stability and impermeability of the opening using dual-rod, called Twin-Jet.
Normally, the soil-cement admixture after the mixing in a fluid state, which will flow out from the horizontal hole. For the purpose to solving this crucial problem, Twin-Jet technology was invented to solidify soft soil and fractured rock instantly.
The fundamental principles of the Twin-Jet method are introduced and sodium silicate(water-glass) is selected as the binder to accelerate the hardening process of an admixture of grout and soil under high pressure of about 10 to 40MPa to create the instant solidification.
A filed test was conducted in the tunnel at OOO in Pusan. Field and laboratory results showed that the admixture can be quick gelled within 10 to 20 seconds. The diameter of jet-grouted column reached 0.6 meter and the strength after 28 days reached 2.0MPa.

ABSTRACT
 1. 서 론
 2. 현장적용
  2.1 현장의 조건
  2.2 Twin-Jet공법의 원리
  2.3 강관 근입 시공방법
  2.4 단계별 시공계획
 3. 결 론
  3.1 수치해석 결과
  3.2 종합 결론
 References

• 김재관(한국기초주식회사) | Kim Jae-Kwan
• 김용현(한국기초주식회사) | Kim Yong-Hyun
• 백재상(한국기초주식회사) | Baek Jae-Sang