论文部分内容阅读
隧道冻结工程中所形成的人工冻结壁为临时支护结构,隧道衬砌结构施工后,冻结壁要进入解冻期,由于冻结壁解冻过程中的地层融沉现象对隧道周边环境影响较大,因此,应建立合理的方法对地表融沉量进行预测,以便于实际施工中采取相应的融沉控制措施。为此,考虑冻结壁的自然解冻过程,基于随机介质理论,建立了隧道水平冻结施工期地表融沉的历时预测模型。并提出冻结壁自然解冻条件下瞬态温度场由平板解冻理论近似求解,基于平板解冻理论和一维情况下已融土层的稳定融沉量计算公式,确定了预测模型中解冻锋面半径和融缩区域内半径这2个关键参数的取值方法。将所建立的预测模型应用于隧道全断面水平冻结工程中,得到了地表融沉随解冻时间的变化规律。研究结果表明,地表融沉在解冻初期增长速度较快,而在解冻后期增长速度减缓,地表历时融沉量与崔托维奇通过试验得出的天然冻土历时融沉量变化规律相一致。
The artificial frozen wall formed in the tunnel freezing project is a temporary supporting structure. After the construction of the tunnel lining structure, the frozen wall should enter the thawing period. Because the thawing of the frozen layer wall has a great influence on the surrounding environment of the tunnel, A reasonable method should be established to predict the surface thawing settlement so that the corresponding thaw settlement control measures can be adopted in practical construction. For this reason, considering the natural thawing process of frozen wall, based on stochastic medium theory, the duration prediction model of surface thawing during tunnel horizontal freezing construction is established. And the transient temperature field of the frozen wall under natural thawing condition is solved by the plate thawing theory. Based on the plate thawing theory and the one-dimensional steady thawing settlement formula, Shrink radius within the radius of the two key parameters of the value. The prediction model was applied to the full-surface tunnel freezing project, and the law of surface thawing settlement with thawing time was obtained. The results show that the surface thawing and thawing settlement increased rapidly in the early thawing period, but slowed down in the late thawing period. The surface lag time thawing settlement coincided with the variation of the monthly thawing settlement of the natural frozen soil obtained by Curtovich.