compression

There are three fundamental types of stress: compression , tension (pulling apart), and shear .

Many materials react differently to tension than they do to compression, and soil and rock are no different.

Those horizontal forces can increase the compression force on one side of the base plate, so you have to account for that in the design.

Where you once had compression throughout the subsurface, now you’ve created a zone of tensile stress, where the material above the tunnel is trying to pull away from itself.

Even with the grout, some of the vertical loads are still going into the anchor bolts that might not have been designed for compression.