It was always likely that the unpropped excavated wall at the rear of the pool deck would collapse if it got significantly wet. We were hoping to avoid this by keeping it well protected from the weather.

Unfortunately we had some very heavy rains and despite being quite well protected by a large tarpaulin, a substantial amount of water managed to find it's way into the wall. It seems the valve on the rain water tank was leaking significant amounts of water as it rained, which ran directly over the tank slab and into the wall.

Collapsed wall
The collapsed wall and damanged piping

The rainwater tank slab is now far too close to the excavated edge. Props are needed. We hastily rented acrow props and installed them diagonally along the slab edge while we excavated under the slab to install permanent props.

Acrow props
Rented acrow props
Temporary props
Two temporary props installed

Once the temporary props installed, we then began the backbreaking task of digging out channels to install three newly purchased props vertically to support the edge of the slab.

Excavated hole for permanent prop

Excavated hole for permanent prop

With the slab safely propped, we were free to start the laborious work of removing all of the collapsed material from the footing trench. Since we'll be needing this material to backfill once the wall is complete, we placed it all nearby on the pool deck area. It would also have taken days to move it by bucket down to the main dirt mountain.

Installed props
Three properly installed props
Dirt on pool deck
New dirt mountain on the pool deck

Wall bracing

Additional bracing added later to the stair-end of the wall.

The collapsing wall took the long horizontal storm water pipe with it on the way down. This is the pipe that we'd previously damaged with the excavator and repaired. There's no rain forecast for the next week so we'll get around to fixing that later or hopefully have the plumber do it directly if we can get the other pipes ready for them prior to the next forecast rain.

After several wasted days, time to move on to finalizing the excavation, but first:

Building the time lapse video.