Cracking my oven on curing fires

[mmarant]

Hoping this post makes it through! I built a small oven, approximately 24" ID. According to FB instructions for a pizza oven, the fire brick and layer of refractory mortar would be sufficient for thermal mass. Going through the serial fires to cure the oven, cracks did develop. On fire #6 and 7, a crack developed on the back side of the vent that progressed across the top of the dome. Last night I fired it to see how the oven would handle a cooking fire and got the oven white hot, however this crack opened up to about 3/8" and I noticed one of my floor bricks moving laterally as if it were moving with the wall upon expansion with the heat. My front vent arch has two cracks and the bricks shift with the heat. Initially, I considered repairing the crack with gasket cement and adding more thermal mass, however now I am leaning toward rebuilding the entire oven.
In one photo showing the side of the oven, I am assuming water is being driven out of the cracks as small areas look wet. The front of the oven just shows the crack and how it runs up the dome. This is all pretty disappointing.
I hope this post gets through as I am unable to locate the first post with the same questions. Any advice would be appreciated on the oven and finding my original post would be great.

Thanks
Matthew