Construction has begun on the Confederation LRT line Bayview Station. The station will be built where the former overpass was over the OTrain Trillium tracks, ie, it is an elevated station incorporating the new bridge.
A series of posts is required to hold up the new station platforms and building structure. The approaches to the station are on landfill from 2001, so it is soft, and original undisturbed soil, upon which the structure should rest, is quite deep down.
Rather than dig a hole to build the supporting posts in, the contractor is drilling holes into the gravel embankment. There are two cylindrical pipes, or sleeves, that fit into each other like a telescope.
The rig drills down into the gravel, and then lifts up the dirt and dumps it to the side. The blue and yellow portions shown here above the drill bit, is then lowered down and attached to the top of the inner cylinder, and the cylinder is pushed down into the void at the bottom of the shaft.
Notice in the picture above that the inner cyclinder is about six feet higher than the outer cyclinder (the top of each cylinder has a reinforced ring portion which if you squint, you can make out just under the drill bit and on the outer cyclinder, just above the gravel slope).
In this picture taken minutes later, the inner cylinder is shown screwed down to be only about 2′ above the rim of the outer cylinder.
The drill portion is reinserted, and then drills a few feet deeper. And the inner cylinder is screwed down another few feet.
Rinse and repeat … as the saying goes.
The gravel is easy to drill through, and in just one day they inserted a long inner cylinder almost as tall as the black crane, maybe 30′.
Later, I assume they will pour a concrete column into the hole, to hold up the new station.