Place, inject, or shoot pellets, sand, or gravel into space above?
I don't think what you are trying will work. You appear to be attempting to dry out a ceiling cavity using silica desiccant, but:

1) Silica gel is a one-use material. Once it's full of water, that's it.

2) I'm a bit worried about the weight; if you're placing this into a ceiling cavity, it'll be supported by the drywall, and basically nothing else. Back of the envelope says 44 lb/sq ft, (assuming you place it one foot deep) plus 40% for water weight, so 60 lb/sq ft. This is a significant weight. Even one inch will give 5lb/sq ft over the entire cavity, and drywall is not designed to provide any support. If you're putting enough silica in the cavity that it's necessary to bring in actual power tools, the weight matters.

If the actual problem you need to solve is removing moisture from a ceiling cavity, there are better ways of doing this. (Solve the issues that allow moisture to accumulate, then add ventilation to encourage evaporation.)