基于宏观冻胀模型的冻土墙基坑支护数值模拟

Numerical simulation of frozen walls in deep pit excavation based on macro frost heave model

为了研究冻土墙形成过程中的非均匀冻胀对冻土墙变形的影响,引入了基于孔隙率变化率的宏观冻胀模型。在分凝势概念的基础上推导了孔隙率变化率的计算公式,对宏观冻胀模型进行了修正,通过试验对模型进行了验证。考虑冻结过程中未冻水含量的改变及由于未冻水含量引起的土体热学力学性质的变化,提出了冻胀变形条件下基坑位移的计算方法。研究结果表明:宏观孔隙率变化率冻胀模型能够合理的反映冻胀现象,可以将其用于预测冻土墙形成过程中的冻胀变形;在冻土墙变形计算中引入冻胀模型更符合工程实际情况。

To study the effect of frost heave on the deformation of frozen walls in deep pit excavation,a macro frost heave model based on the modified porosity rate function was used.The porosity rate function was promoted based on the segregation potential,and then the test verification was performed.By using the modified frost heave model,the distributions of unfrozen water and induced nonhomogeneous properities were considered in the FEM analysis.The results show that the macro frost heave model can predict frost heave effectively,and the affect of frost heave on the deformation of frozen walls in deep pit excavation should be considered.