In order to study the interaction mechanism between liquid-phase suction and solid-phase ice pressure in frozen soil / rock

the theoretical ice pressure equations under different boundary conditions are first unified according to the fundamental thermodynamics. Then

by combining the generalized Clapeyron equation and the Gibbs-Thomson equation

the freezing temperature equation of liquid phase water at curved interface is given on the basis of interpretation of the physical significance of liquid-phase suction and solid-phase ice pressure. Finally

the freezing temperature equation is introduced into the frozen capillary model

and the liquid-phase suction equation is substituted into Darcy's law to verify the action mechanism of solid-phase ice pressure and liquid-phase suction respectively. The results show that: 1) The theoretical ice pressure in equilibrium state is only linearly related to temperature and has nothing to do with the boundary conditions. 2) The liquid-phase suction stems from the difference between the theoretical suction and the offset factor of solid-phase ice pressure

and it is the unified driving force for water migration

and when the solid-phase ice pressure approaches the theoretical ice pressure

the liquid-phase suction tends to zero. 3) The solid-phase ice pressure is an absolute pressure

which can offset the liquid-phase suction

while the liquid-phase suction is a relative suction and cannot offset the solid-phase ice pressure. 4) The total pressure in the pores is only the solid-phase ice pressure and it can reach the theoretical ice pressure in equilibrium when the capillary is frozen

so it follows the formation mechanism of segregation ice by "ice pressure method". This research reveals the interaction mechanism between liquid-phase suction and solid-phase ice pressure in frozen soil / rock

which has high theoretical value and scientific significance for improving the existing frost heave theory.