굴착단계별 수평 지보재 대체 앵커의 안정성 해석

초록

As underground space development in urban areas increases, excavation support methods that can ensure stability within confined urban sites are becoming increasingly important. Horizontal struts occupy the excavation space, while ground anchors may extend beyond the site boundary, limiting their applicability in urban areas. In this study, staged excavation stability analysis was performed for a horizontal support-replacing anchor system. Numerical analyses were conducted under two-dimensional plane strain conditions using PLAXIS 2D, and wall horizontal displacement, ground surface settlement, and factor of safety were evaluated through staged construction analysis and the shear strength reduction method. The results showed that wall horizontal displacement increased as the anchor inclination angle increased, especially under high-angle conditions of 80° or greater. Increases in bonded length and free length reduced displacement to some extent, but their influence was limited beyond a certain length. In contrast, increasing the jacking force reduced wall horizontal displacement under the same inclination angle. In addition, comparison with field measurements indicated that the maximum horizontal displacement obtained from the analysis was larger than the measured value, indicating that the numerical analysis provided conservative estimates of wall displacement. Therefore, in the design of horizontal support-replacing anchors, the anchor inclination angle and jacking force should be considered together while satisfying the minimum bonded length and free length requirements.

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