Figure 1. Pass of a cleaning head over a 2-inch sand layer sitting on a set of concrete blocks that are not confined. The video shows the removal of the sand, without water escape.
I apologize for the quality of the tape, but these were research records that we were making of the experiments, merely to get certain data from them and they were not intended for transmission when made.
The second point I wanted to include was that of the ability to use the same design to cut a trench in harder material, again without the spreading of water beyond the trench. The material is a relatively weak cement.
Figure 2. Four passes over a weak cement to show that all the material removed can be aspirated at the time of excavation.
The tapes show how one can cut trenches in either soil or light rock fairly quickly and without making much disturbance outside the slot. Obviously the material removed can be collected in a vacuum truck and poured back into the trench after the trench work is complete.
In a later post I will show how this can also be used as part of a tool we developed to find, expose and then neutralize landmines.