Numerical analysis of interaction between freezing wall and shaft lining in deep alluvia

The load of outer shaft lining during freeze sinking mainly originates from the interaction between the freezing wall and the outer shaft lining, whose growth greatly relates with the compressibility of polystyrene foam board between them. In order to study the load in deep alluvia, taking a freeze sinking project in East China as the background, the interaction between the freezing wall and the shaft lining is studied by adopting the elastic-plastic and creep constitutive models for frozen soils. The results show that there is significant rheological interaction between the freezing wall and the shaft lining. The existence of foam board and its compressibility significantly reduce the value of the interaction pressure, especially P_epc and affect its growth rate and growth rule. During the gradual decrease of compressibility of foam board until the cancelation of foam board, the interaction pressure first approximately linearly grows at low speed, then gradually nonlinearly grows at high speed, and it will pose a threat to the early safety of shaft lining. Therefore, in the design and construction of freeze sinking, the foam materials and thickness should be carefully studied and determined based on the rheological characteristics of freezing wall.