접힘홈이 형성된 띠형 섬유보강재를 사용한 패널식 보강토옹벽의 현장계측 연구

Field Monitoring of Panel-type Reinforced Earth Walls Using Geosynthetic Strip Reinforcement with Folding Grooves

Abstract

본 연구에서는 새로운 형태의 패널식 보강토옹벽에 대한 현장 적용성 및 구조 안정성을 평가하기 위하여 두 개소 현장에서 현장계측을 수행하였다. 새로운 형태의 패널식 보강토옹벽은 접힘홈이 형성된 띠형 섬유보강재를 패널식 전면벽체에 매립된 C형 삽입구를 통해 직접 연결함으로써 보다 일체화된 구조를 형성시킨 보강토옹벽이다. 현장계측에서는 보강토옹벽의 시공 중 및 완료 후에 발생하는 전면벽체의 수평변위와 띠형 섬유보강재의 인장변형, 전면벽체에 작용하는 수평토압 등을 측정하고 분석하였다. 분석 결과, 보강토옹벽 시공 완료 후에 전면벽체에 작용하는 최대 수평토압은 Rankine 토압의 2/3 이하 수준이고, 전면벽체에 발생된 최대 수평변위는 보강토옹벽 높이의 0.5% 이하 수준이며, 보강재에 유발된 최대 인장변형률은 1.0% 이하로 나타나 두 현장의 보강토옹벽이 모두 안정한 상태를 유지하고 있음을 알 수 있었다.

A new style of panel-type reinforced earth wall is a more integrated structure by connecting the geosynthetic strip reinforcement with a folding groove directly to the front panel through C-shaped insertion hole embedded in the panel. In this study, field measurements were conducted on two reinforced earth walls constructed at different sites to assess the field applicability and structural stability of the new style of panel-type reinforced earth wall. The horizontal displacement of the front panel, tensile deformation of the geosynthetic strip reinforcement, and horizontal earth pressure acting on the panel were measured and analyzed through the field measurements. According to the field measurements, after completion of the reinforced earth wall construction, the maximum horizontal earth pressure applied to the front panel was less than two-thirds of the Rankine earth pressure, and the maximum horizontal displacement of the front panel was less than 0.5% of the wall height, and the maximum tensile strain generated on the reinforcement was less than 1.0%. Therefore, it was found that two reinforced earth walls constructed at different sites remained stable.

Fig. 1. Schematic view of the new style of panel-type reinforced earth wall

Fig. 2. Geosynthetic strip reinforcement used for construction of reinforced earth walls

Fig. 3. Grain size distribution curve of backfill material (2nd Yeongdong Expressway site)

Fig. 4. Construction of the TieRect panel-type reinforced earth wall (Palyong Tunnel site)

Fig. 5. Cross-sectional view with measurement point

Fig. 6. Installation of instrumentation

Fig. 7. Lateral earth pressure according to wall height (2nd Yeongdong Expressway site)

Fig. 8. Lateral earth pressure according to wall height (Palyong Tunnel site)

Fig. 9. Measurement result of inclination of wall facing (2nd Yeongdong Expressway site)

Fig. 10. Measurement result of horizontal displacement of wall facing (Palyong Tunnel site)

Fig. 11. Tensile strain of reinforcements according to construction stage (2nd Yeongdong Expressway site)

Fig. 12. Tensile strain of reinforcements according to construction stage (Palyong Tunnel site)

Table 1. Installed location of instrumentation devices for field monitoring