In landslide stability analysis and design calculation

the residual strength value of slip zone soil is often selected

but many studies have found that the slip zone soil has self-healing phenomenon in the holding period

which is manifested as the increase of shear strength. For the red bed landslide dominated by creep

the application of recovered strength in the stability analysis of a reactivated landslide should be considered. The shear-hold-shear experiments are carried out on soil samples from a typical red bed landslide to determine the healing of shear zones under different vertical stresses and holding durations. The experimental data show that

the strength recovery occurs in the tests under different pressures

but the recovered strength will lose in very small shear displacement; the strength recovery value of the shear zone becomes larger and larger with the increase of holding time; self-healing of shear zones is more dependent on holding time than vertical stresses. The obtained friction coefficient values is fitted with the empirical formula of fault strength recovery

and the value of constant A under different vertical stresses can be obtained. The value of constant A can be applied to stability analysis of the reactivated landslide.