Some astronauts have just arrived in Mars orbit! They're fixing to set up a small refueling station/outpost on Deimos. One problem, how might they keep their small habitat and associated structures from simply floating away at the slightest jolt in Deimos's low (only 0.003 m/s2) gravity?
Don't anchor at all.
Use Deimos as a navigation point, and build the base --with spin-- a couple miles off.
The costs of living and working in microgravity are enormous, and you have an opportunity to avoid them here. With spin, your crew can pump fuel more easily...and use real toilets among many other benefits.
Gravity, as you point out, is not sufficient to hold something on the surface.
You would need something to anchor your base to the rock beneath: screw piles
Screw piles, sometimes referred to as screw anchors, screw-piles, helical piles, and helical anchors are a steel screw-in piling and ground anchoring system used for building deep foundations. Screw piles are manufactured using varying sizes of tubular hollow sections for the pile or anchors shaft.
The pile shaft transfers a structure's load into the pile. Helical steel plates are welded to the pile shaft in accordance with the intended ground conditions. Helices can be press-formed to a specified pitch or simply consist of flat plates welded at a specified pitch to the pile's shaft. The number of helices, their diameters and position on the pile shaft as well as steel plate thickness are all determined by a combination of:
- The combined structure design load requirement
- The geotechnical parameters
- Environmental corrosion parameters
- The minimum design life of the structure being supported or restrained.
Screw piles are wound into the ground much like a screw into wood.
Once you have the screw piles in place, you either directly build on them or use cables to keep the position of the base.
Reminder: you need to investigate the geology of the body before placing a random screw pile on it.
Hit it hard just before you land. Soften it up to molten. You could use a bomb or thermite. Better though would be an incoming impactor which passes your station and hits Deimos at speed.
Settle down into the molten rock. It will be toasty warm. Stay inside your ship for just a bit. Play Scrabble.
The molten rock will resolidify. Hopefully you like the view because you wont be moving after that.