联络通道冻结法施工三维力学分析

Three-dimensional Mechanical Analysis of Artificial Ground Freezing Method in Cross-adit Construction

应用人工冻结土体技术开挖隧道的联络通道,涉及到土体冻结的热力学作用以及冰冻土体与隧道结构相互影响等一系列复杂的物理力学过程。采用FLAC3D建立主隧道、联络通道及冻结管的三维数值模型,综合考虑了温度计算、冻土与非冻土的转变及土体的冻胀作用,研究了人工冻结法对隧道管片及周围土体的力学响应。通过对冻胀率参数敏感度分析,研究土体冻结变形、冻胀力及隧道管片内力的变化,所得到的初步结果对冻结法施工有着实际的工程意义。

The application of the artificial ground freezing method for the construction of cross-adits is a complex mechanical and thermal process of the tunnel structures and the freezing ground. A 3D numerical simulation model is established using FLAC3D in this paper to study the response of the tunnel lining and the surrounding ground during the freezing and excavation. By this model, the main tunnel lining, the freezing pipes and the cross-adit excavation are simulated and the mechanical responses of the tunnel and the ground are investigated. By integrating the phase change of the frozen/unfrozen soil and the soil frost action into this thermal-mechanical analysis, the preliminary results of the soil heave displacements, the soil heave pressures and the lining stresses during the freezing and excavation process have been ob- tained, which are useful for the construction design.