When we apply the option Reset displacements to zero, we reset the displacements at the BEGINNING of the phase. This means that any displacement in the model due to changes, e.g., load changes, structural elements being activated, soil activated/deactivated, can still occur in this phase: the phase just starts with zero displacements.

This option should be selected when irrelevant displacements of previous calculation steps are to be disregarded at the beginning of the current calculation phase, so that the new calculation starts from a zero displacement field. For example, deformations due to gravity loading are physically meaningless. Hence, this option may be chosen after Gravity loading to remove these displacements. If the option is not selected, the incremental displacements occurring in the current calculation phase will be added to those of the previous phase. The selection of the Reset displacements to zero option does not influence the stress field.

The use of the Reset displacements to zero option may not be used in a sequence of calculations where the Updated mesh option is used. However, if an Updated mesh analysis starts from a calculation where the Updated mesh option is not used, then the Reset displacements to zero option MUST be used in this Updated mesh analysis.

Reset small strain

This option should be selected when an existing state of the small-strain tensor in the HS small model, as reached at the end of the previous phase, is to be disregarded. As a result, the soil will behave as a 'virgin soil' without strain history. Other state parameters are not affected by this option. If it is the user's intention to reset all state parameters, then the option Reset State Variables should be used.

Note: this option to Reset small strain is automatically checked when you select the Reset displacements to zero option.

Reset state variables

This option should be selected when the values of the state parameters in advanced soil models, as reached at the end of the previous phase, are to be disregarded. As a result, the soil will behave as 'virgin' soil. The reset parameters for the Plaxis models are given in the table below.

Material model	Parameter
Soft soil, Soft soil creep, Modified Cam-Clay, Hardening soil, Hardening soil small-strain	2D 2019 and later: pp reset to the OCR value from the Initial tab of the material set(1) 3D AE, 3D 2016 and later: pp reset to the OCR value from the Initial tab of the material set(1) 2D 2018 and earlier: pp reset to current effective stress state (OCR=1.0)
Hardening soil small-strain	Strain history tensor reset to zero
Hardening soil, Hardening soil small-strain	Mobilised shear reset to current effective stress state

⁽¹⁾ Note that resetting the OCR will only adjust the preconsolidation pressure and not the current stresses. Therefore the user should be aware that after resetting the OCR the current stress state (particularly the ratio between horizontal and vertical stresses) may not be representative for the new OCR.