Abstract

A pneumatic landslide generator was developed specifically for the investigation of landslide generated impulse waves in reservoirs, lakes, bays or oceans in a two-dimensional physical laboratory model. The landslides were successfully modelled with an artificial granulate. The pneumatic landslide generator was designed to control the slide impact characteristics and enable exact repro-duction and independent variation of single dynamic slide parameters. The two pneumatic linear drives catapulted the landslides to velocities up to 7.3 m/s on an acceleration distance of less than 0.9 m. The operation of linear drives 3.6 times beyond their certified velocity range is highlighted. Total masses of up to 174 kg were accelerated. The slotted cylinders enabled a compact mechanical design and a stroke length equal to 70 % of the overall cylinder length. The pneumatic deceleration by temporary airflow and pressure gradient reversal is presented. Real time valve response problems in high-speed applications are discussed and solved with preset trigger signals programmed to the pneumatics control unit. The behaviour of the whole pneumatic system was successfully simulated with the computer aided cylinder optimisation system software (CACOS). The measurements and numerical simulations are compared.

Keywords: pneumatic linear drives, slotted cylinders, high-speed application, large moving mass, airflow reversal, pneumatic deceleration, external shock absorber, real time problems, CACOS numerical simulation, landslide impacts, impulse waves