Simulating Anisotropy Behavior of Coal


I am trying to perform a UCS simulation on coal with face cleats, butt cleats, and bedding planes in it. I created the model using the block-cut joint-set command with a statistical distribution for each joint network (see attached figure). I could calibrate the pre-peak and post-peak behavior of the model, however, the lateral strain in the Y-direction is relatively low compared to the lateral strain in the X-direction in the post-peak region of the stress-strain curve (see attached figure). As I am installing a rockbolt element in the Y-direction in the model, the axial force in the rockbolt element is way lower than what we observed during the laboratory tests for similar testing scenarios (due to low displacement in the Y-direction). I played with all the joint and zone properties and was still unable to increase the displacement in the Y-direction. I tried increasing the rockbolt stiffness properties, but still, the axial force in the rockbolt is 10 times lower than what we observed in the lab. Is there any way we can fix this problem? Is my approach to simulate the joint network correct?


Without running the model, this seems to be just a result of the joint orientations. There are steeply dipping joints in the x direction that will cause a lot of movement in the x direction, but only vertical joints in the xy plane, so the only movement you will get in the y direction is due to tensile opening of those joints.