2. Magnetic ring layered strata subsidence monitoring well: the main purpose is to judge the compression characteristics of the subterranean stratum and the compression of soil layers at various depths. Its structure is to anchor the magnetic induction ring to different depths of the formation in advance, then use the radio wave induction detection equipment to measure the depth of each induction ring from the surface, and analyze the compression of each layer to understand the subsidence changes at different depths of the formation. And then find the main compression depth and compression range under the stratum, so it has the characteristics of multi-layer and flexible setting monitoring level.