Hello reply might be a little late but here is some info anyway.
There a quite a few to do by taxi/bus. There a three is Safa park GC37JMX, GC37JM2 and GC37V21. There is a Multi Cache by the Mall of the Emirates, 2 by Dubai mall and 1 by Ibn Batta mall. Lastly there is one called Dubai Promenade GC1BXPY which is worth a visit. these all are quite easy to get to by taxi/Metro or Bus. And you can get a Taxi easily back. Most of these a sadly nanos and mircos (Which sadly comes with urban caching). There are some bigger ones like the old rocker of Dubai GC30RAZ but are a little harder to get a taxi back from. Do some research as there are some nice larger caches in some great beach locations. Good luck