The shallow slab slides which occurred in the area around the Mineoka uplift zone in chiba prefecture were detaily described and discussed on the mechanism of generation and corrective design.
The slab slides in this area are recognized to have been formed by the repeated slidings. Repeated slow slides are interpreted to have been mainly caused by the generation of small caves (so-called bora) and successive connection of caves (so-called bora-sawa). The each moving mass has the unit thickness of about 3-5m and is mostly composed of cohesive soil with N≤20, Nsw≤100.
Corrective design of surface and trenches was used for the portection of the slides. As a results, the lowering of water level was expected to be 0.5 m and the safeness for the sliding rose 10%.