Sure, these exist as pressure mats. Many are waterproof, for example they are often used as a “doorbells“ on houseboats, but also to indicate when someone is approaching an open bay in a commercial building.
But you almost always have to put the part of the system which is actually going to transmit the signal above ground or the signal won’t get through. So I don’t know if that’s going to help you or not. You can run a cable from the pressure mat itself to the transmitter device, but as a practical matter these are usually limited to about 2 m.
In Addition, these generally have to be buried very close to the surface or the change in pressure isn’t sufficient to set them off. So that’s another factor to take into account.
See the following thread (The topic title is a clickable link)
(I should say also that you can’t do it with motion sensors of the sort that are typically used for a low cost home automation sensor. Those are almost all PIR sensors, passive infrared, and the infrared will not travel through the dirt. but the pressure sensors can work with the caveat noted above.)