You'd think there would be more updates on this one.
Construction started some time before May 22, 2013 Piling was completed in December 2013.
Geotechnical investigation (soil testing) took place in 2008. Work on the foundation is currently scheduled to begin towards the end of 2012. However, statements that construction will begin soon have been made since 2008, but have been postponed each time. In August 2011, the start of construction was slated as "no later than December," with some saying "immediately," and that construction is imminent. This meant the tower was expected to be completed in 2017, though at that time it was also possible that it could still have been completed by the date the media continued to publish, which was the prior estimate of late 2016. Only if construction had begun promptly and went smoothly could a late 2016 completion be achieved
Designs for the foundation were in place by early August 2011 and the contract for the piling was being tendered. On 16 August 2011, Langan International officially announced their involvement and that the foundation and piling had to be uniquely designed to overcome subsurface issues such as soft bedrock and porous coral rock, which normally could not support a skyscraper without settling. The foundation will be similar to that of the Burj Khalifa, but larger. It is expected to be around 60 metres (197 ft) deep with a concrete pad of around 7,500 m2 (80,729 sq ft). The concrete will have to have low permeability to keep out corrosive salt water from the Red Sea. Its depth and size is also considered to be an indicator of what the tower's final height will be.The piles will be up to 200 metres (656 ft) deep and the pad over 300 feet (91 m) across, yet even still the building, which will weigh over 900,000 tons, is expected to settle. The idea is that it settles evenly enough so that the building doesn't tip or put undue stress on the superstructure. Computer modeling programs performed tests at the site to confirm that the foundation design would work. A later design for the foundation, to be constructed by Bauer in 2013, calls for 270 bored piles up to 110 metres (361 ft) deep which have to be installed into the difficult ground conditions.
Construction of the building will rely on cutting edge technology, including the high-strength reinforced concrete and the pumps used to elevate it to record heights, similar to what was used during Burj Khalifa's construction. Bob Sinn, principal of Thornton Tomasetti states, “Concrete quality is getting better and better, as is pumping technology. There have been very strong advances in reinforced concrete over the last 20 years." He continued, “Kingdom Tower is certainly feasible. It’s not a structural challenge. Technically I think a 2 km (6,562 ft)-tall tower could be done, but I don’t think it will be done anytime soon.”
So there you have it, they will be working on the foundation for a while yet but maybe later this year we'll get some pics