Abstract
Tension cracks often occur on the ground surface of steep slopes after heavy rain. However, the expansion of these cracks doesnot continue for a long time. This phenomenon of displacement is called a“ quasi landslide” because it does not indicate the occurrenceof new landslides.
The phenomenon is caused by the rheological deformation of soft clay layers in debris deposits and the increase of shear stressby saturation of the soil near the ground surface results in the deformation. The amount of rainfall, pattern of rainfall and the formationof the slope are closely related to the phenomenon.
By observing this kind of deformation using a tiltmeter within the hole, special landslide prevention measures in the slope arenot needed.
