erode

With those two conditions, any soil overlying a dissolution feature runs the risk of eroding away from the inside, eventually leading to a sinkhole.

Finally, rather than physical erosion, some materials are soluble in water, just like sugar or salt, and can be eroded just by dissolving into the groundwater over time.

This means that a constant battle of seepage flowing in from the bottom of the caisson, or much worse, unstable soils that can rapidly erode and allow the caisson to flood.

You can add more injection wells to increase the speed of recharge, but above a certain pressure, some funny things start to happen: underground formations break apart and erode in a phenomenon called hydraulic fracturing or just fracking.