The study looked at how tunnels behave during construction compared to what was predicted. By analyzing data from two tunnels being built, researchers found a way to estimate how much the tunnel will change from the start to the end. They used two methods to predict these changes, and both methods showed a clear relationship between the initial and final tunnel movements. The difference between the two methods was not very big, showing that both ways can be used to estimate how much a tunnel will change over time.