Negative pore-water pressure can be made by seepage and unloading, and it is directly associated with capillary
water. The capillary water and the relationship with negative pore-water pressure were theoretically deduced by analyzing the
parameters of capillary water ascension height, surface tension, osmotic coefficient, coefficient of viscosity and void ratio. In the
meantime, by analyzing the coefficient of stability of limit equilibrium，the borehole忆s timing stability from cohesion and
capillary tension is quantitatively calculated, which is directive to engineering practices.