i think it will work. i plan to run 6 1080ti on the ax1500i on lower TDP and solo mining.

but your 1070s also require 6pin and 6+2pin right? you will be short on cables as the ax1500i comes with 2 cables that are dual 6+2pin and 6 cables that are single 6+2pin.

then get these splitters?

http://www.ebay.com/itm/1x-PCI-e-8pin-to-Dual-8Pin-PCIe-8pin-2x-6-2pin-Graphics-Video-Card-Power-Cable-/262845994260