中文摘要：

基于杭州沿江运河隧道工程,采用有限差分数值软件FLAC~（3D）对开挖面被动失稳进行研究。根据数值分析中失稳模式提出局部被动失稳二维机动场模型并采用上限分析法推导开挖面极限支护压力。对运河隧道工程进行支护压力上限解分析。研究结果表明：支护压力过大会引起开挖面局部被动失稳,开挖面局部失稳区域底部至隧道拱顶距离与隧道直径的比值主要受覆土厚度的影响,土体摩擦角变化对其影响较小。被动失稳引起开挖面前方地表1.5倍开挖直径范围内隆起。支护压力上限解分析结果与数值计算结果吻合良好,该研究为盾构隧道施工中支护压力上限值确定提供了合理理论依据。

英文摘要：

Based on Hangzhou canal tunnel project, the explicit differential code FLAC3 D was applied to investigate the blow-out failure of tunnel face. The case of Hangzhou canal tunnel was investigated, an agreement between the upper bound solution and numerical solution was discovered. The results show that partial failure existing on the up part of face is found instead of integrate failure. The ratio of failure height to tunnel diameter is majorly affected by the cover depth, but little influenced by frictional angles of soils. Furthermore, on the ground surface, the soil upheaving starts where is above the tunnel face. The ratio of upheaving length to the tunnel diameter is 1.5. This study improves the evaluation of the upper limit support pressure for the blow-out failure and the relevant theoretical foundation is cemented.