广州某地铁人工冻结法施工热力分析

以广州某地铁采用人工冻结法施工为例,考虑相变和衬砌水泥水化热的生成,根据带相变瞬态温度场的热量控制微分方程,采用伽辽金法推导出的有限元计算公式计算分析了此地铁人工冻结施工过程中的温度场分布规律.并根据温度场的分布特点,确定了开挖时的人工冻结壁厚度.最后,对冻结壁和其周围土体分别应用不同的力学本构模型进行施工过程的力学模拟.结果表明,采用人工冻结法作为一种辅助的施工方法,不但能满足施工过程中结构的强度要求,而且能满足环境沉降量的要求.

Thermal and Mechanical Analysis of the Artificial Freezing Method Applied to A Subway Tunnel in Guangzhou

In this paper,a subway tunnel in Guangzhou constructed by employing artificial freezing method is taken as an engineering example.Firstly,based on the governing differential equations of the transient temperature field with phase change and heat of hydration of lining cement,the temperature fields are analyzed through using finite element formulae deduced by Galerkin method.Then,according to the features of the temperature field,a frozen wall is determined,and the stresses and displacements of soils are computed and analyzed through using creep constitutive model for frozen soil and elastoplastic constitutive model for unfrozen soil.The results show that,as an auxiliary method to construct a tunnel,applying artificial freezing method to construct tunnel can satisfy not only the strength requirement of structures but also the requirement of settlements of ground surface.