FAQ - UniSettle
Q1. In UniSettle, what is the input for Unloading Consolidation Factor cvr?
Unloading results in a reduction of pore pressure that then gradually returns in a process similar to the dissipation of excess pore pressure from loading a soil. Few textbooks address the time development of unloading. UniSettle calculates the time effect of loading using the coefficient of consolidation. However, recognizing that in many cases the unloading process is faster than the loading, UniSettle uses the cvr to calculated the time development in unloading. UniSettle multiplies the cv-value with the cvr-factor (always larger than unity; a factor smaller than unity is not accepted) to enable a User to simulate the faster process.
Q2. If a layer drainage condition is set to immediate does UniSettle still calculate a rebound movement for unloading?
Yes, when the input is a reduction of the applied stress (e.g., due to an excavation or removal of load, UniSettle will calculate an immediate "negative" settlement using the immediate modulus (Ei or Eir) if such is input. Note, whether or not an immediate modulus is input, if a modulus number, m or mr, is input, UniSettle will also calculate the consolidation settlement represented by the modulus number and the consolidation input. Loading and unloading are treated similarly, that is.