基于随机介质理论的地表冻胀预测及其参数敏感性分析

SURFACE FROST HEAVE FORECAST AND PARAMETER SENSITIVITY ANALYSIS BASED ON RANDOM MEDIUM THEORY

为预测人工冻结法施工引起的地表冻胀量,以广州某地铁为研究背景,运用随机介质理论建立水平冻胀计算模型,并对其中涉及的冻结锋面半径、冻胀区域外半径进行了探讨,分析了对地表冻胀量有影响的各参数的敏感性。由计算结果得出水平冻结引起的地表垂直冻胀量呈正态分布,在隧道中心处达到最大值;参数敏感性分析得出各参数敏感度从大到小依次为常数、土体冻胀率、隧道埋深、土体主要影响角正切值、冻结管布圈半径;最大垂直位移随着布圈半径、常数、冻胀率、土体主要影响角正切值的增大而增大,随着埋深的增大而减小。通过与实测数据进行比较验证了该模型的可靠性,为今后同类工程的设计与施工提供了参考。

To forecast the surface frost heave caused by artificial freezing method, this paper takes a subway project of Guangzhou study background, uses random medium theory to establish a calculation model for U-shaped horizontal frost heave, and discusses the determination of two key factors involved in the calculation model, including radius of freezing front and outer radius of frost heaving area. The sensitivity of various parameters influencing surface frost heave is analyzed. The calculation result shows that surface frost heave caused by horizontal freezing is a normal distribution and reaches its maximum value at tunnel center; parameter sensitivity analysis finds that the sensitivity of different parameters is constant, soil mass frost-heaving ratio, embedded depth of tunnel, tangent value of angle mainly influenced by soil mass and radius of frozen tube distribution circle （listed in a decreasing sequence）; the maximum vertical displacement increases after increase of radius of distribution circle, constant, frost-heaving ratio and tangent value of angle mainly influenced by soil mass and decreases after increase of embedded depth. The to measured data, providing references for future