盾构进出洞时端头土体纵向加固范围研究

为研究盾构进出洞时端头土体纵向加固范围的问题,本文基于极限平衡理论,建立盾构进出洞时端头加固土体二维稳定性分析的理论模型,推导了相应的端头土体纵向加固尺寸的计算公式,进而对一工程实例进行了计算分析得到其端头土体纵向加固长度至少应为7.43 m,最后讨论了端头加固土体粘聚力、内摩擦角、隧道直径等重要参数对端头土体纵向加固范围影响。研究结果表明:端头加固土体的粘聚力、内摩擦角对端头土体纵向加固范围影响显著,随着端头加固土体的粘聚力和内摩擦角增大时,端头土体纵向加固长度都将会减小。隧道直径越大,端头土体纵向加固长度也越长。

Study on the Longitudinal Soil Reinforcing Scope for Shield Tunnelling Breakthrough

In order to study the problem of longitudinal soil reinforcing scope for shield tunnelling breakthough, based on the limit equilibrium theory, the 2D theoretical analysis model for the stability of soil reinforcement was established and the corresponding formulae on the size of longitudinal soil reinforcement were obtained by theoretical derivation. Then, an engineering example was analyzed and calculated that the length of longitudinal soil reinforcement should be at least 7.43 m. Finally, cohesion and internal friction angle of the soil reinforcement, the diameter of tunnel and other important parameters were discussed, which influenced the length of longitudinal reinforcement scope. The research results show as follows: cohesive and internal friction angle of the soil reinforcement are sensitive to the length of longitudinal reinforcement. When cohesive and internal friction angle of the soil reinforcement increase, the length of longitudinal reinforcement is reduced. The larger the diameter of tunnel becomes, the longer the length of longitudinal reinforcement will be.