쏘일네일링 공법은 굴착이나 사면안정을 위해 가시설이나 영구용으로 국내에서 널리 이용되고 있다. 특히, 도심지 근접 굴착시 쏘일네일링 공법 적용시 고려사항은 벽체변위와 네일의 인장등 이다. 본 연구는 국내 여러 암반층을 포함하는 다층토 지반의 11개 쏘일네일링 현장에서 굴착단계별 네일의 인장력 거동을 계측자료와 역해석을 통하여 고찰하였다. 역해석 결과 네일의 최대인장력은 계측값의 50% 정도로 낮게 나타났고, 벽면에서 가상 파괴활동면까지의 거리를 주동영역거리라 할때 CLOUTERRE 보고서와 Cartier & Gigan이 각각 제안한 최종굴착 깊이(H$_{f}$ )의 0.3$H_f$,0.5$H_f$,에 비해 계측결과는 크게 나타났으며, 역해석은 이들이 제안한 범위내에 포함되었다.
Soil nailing type of retaining structures has been widely used in Korea far the purpose of the temporary and permanent support in excavations and slope stability. The important factors in application of soil nailing systems in urban excavation site nearby the existing structures are the displacement of the wall and tensile farce of the nails, etc. In this paper, the fled back analyses are carried out at 11 excavation sites to investigate the behavior of tensile farce of nails at stepwise excavation in the multi-layered strata including various rock layers. The results of the fled back analysis are less than about 50% of the measured ones. The distance of active zone by measurements are shown almost larger than that of fled back analysis when the distance of active Bone is defined from the surface of wall to the potential failure surface. And the results of fled back analysis are within the range proposed by the project CLOUTERRE and Cartier & Gigan (1983) which were 0.3$H_f$, and 0.5$H_f$, of the final excavation depth ($H_f$,) respectively, but the values of the measurement were larger than these values.
