Open shallow landslides occur regularly in a wide range of natural terrains. Generally, they are difficult to predict and result in damages to properties and disruption of transportation systems.
In order to improve the knowledge about the physical process itself and to develop new protection measures, full-scale experiments were conducted in Veltheim, Switzerland. Material was released down a test slope into a flexible barrier. The flow, as well as the impact into the barrier, was monitored using various measurement techniques. Laser devices recording flow heights and a special force plate measuring normal and shear basal forces, as well as load cells for impact pressures, were installed along the test slope. In addition, load cells were built in the support ropes and retaining cables of the barrier to provide data for detailed back-calculation of load distribution during impact. A release mechanism simulating the sudden failure of the slope was designed such that about 60 m³ of mixed earth and gravel saturated with water can be released in an instant.
The analysis of cable forces coupled with impact pressures and velocity measurements during a testing series now allows one to develop a load model for the barrier design. The first numerical simulations of the impacted barrier lead to structural improvements of new protection measures. It appears that special adaptations to the system, such as smaller mesh sizes, a special ground-barrier interface compared to normal rock-fall barriers and channelized debris flow barriers, are necessary in order to improve the retention capacity of shallow landslide barriers.
Detailed analysis of the friction coefficient in relationship with pore water pressure measurements gives interesting insights into the dynamic of fluid-solid mixed flows. Impact pressure dependencies on flow features are analyzed and discussed with respect to existing models and guidelines for shallow landslides.