2.2 Phenomenological Methods
53
Fig. 2.7 Enlarged plots of the lower part. a t = 0; b t=80m
diameter to several diameters of pebble, which are enclosed by several pebbles. This
indicates that the propagation of the voids induces the quasi-static dense pebble flow.
Additionally, the pebbles near the corners and bases flow very slowly and look
completely “motionless”. As time goes on, the “motionless” area will gradually
decrease, although perhaps there would be yet several pebbles that remain there
forever.
2.2.5 Pre-filled Core Method
Different from the pre-filled stripes method, the pre-filled core method is designed
to display the horizontal movement of the pebble packing. In the beginning, a central
column of black pebbles was pre-filled in the colorless pebble packing. Then, black
pebbles were added in the middle, and colorless were added on both sides at the ratio
of 14:122:14, which was matched with the width of the central column. At the same
time, pebbles were discharged from the bottom with 150 pebbles per minute. The
guide plates were installed to prevent the pebble’s bouncing at the upper free surface.
Snapshots were taken at intervals to record the experimental process, as shown in
Fig. 2.8.
It should be noted that the pre-filled width of the core ought to be consistently
matched with the ratio of the loading pebbles. The previous experiment has already
proved that under the ratio of 14:122:14, we can get a central region with a width of
440 mm, so the preloaded central core of black pebbles is 440 mm wide.
Firstly, the topside of the pre-filled core almost remains unchanged, where the
horizontal motion is zero, while the underside gradually becomes narrow, where the
53
Fig. 2.7 Enlarged plots of the lower part. a t = 0; b t=80m
diameter to several diameters of pebble, which are enclosed by several pebbles. This
indicates that the propagation of the voids induces the quasi-static dense pebble flow.
Additionally, the pebbles near the corners and bases flow very slowly and look
completely “motionless”. As time goes on, the “motionless” area will gradually
decrease, although perhaps there would be yet several pebbles that remain there
forever.
2.2.5 Pre-filled Core Method
Different from the pre-filled stripes method, the pre-filled core method is designed
to display the horizontal movement of the pebble packing. In the beginning, a central
column of black pebbles was pre-filled in the colorless pebble packing. Then, black
pebbles were added in the middle, and colorless were added on both sides at the ratio
of 14:122:14, which was matched with the width of the central column. At the same
time, pebbles were discharged from the bottom with 150 pebbles per minute. The
guide plates were installed to prevent the pebble’s bouncing at the upper free surface.
Snapshots were taken at intervals to record the experimental process, as shown in
Fig. 2.8.
It should be noted that the pre-filled width of the core ought to be consistently
matched with the ratio of the loading pebbles. The previous experiment has already
proved that under the ratio of 14:122:14, we can get a central region with a width of
440 mm, so the preloaded central core of black pebbles is 440 mm wide.
Firstly, the topside of the pre-filled core almost remains unchanged, where the
horizontal motion is zero, while the underside gradually becomes narrow, where the