Consolidation analysis by degree of consolidation or expwp

Hi Jamal,

In a Consolidation analysis, the following options are available:

1. Consolidation and simultaneous loading in the sense of changing the load combination, stress state, weight, strength or stiffness of elements, activated by changing the load and geometry configuration by means of Staged construction. 
2. Consolidation without additional loading, until all excess pore pressures have decreased below a certain minimum value, specified by the Minimum excess pore pressures parameter.
3. Consolidation without additional loading, until a desired degree of consolidation, specified by the Degree of consolidation parameter, is reached. 

The staged construction workflow that you mentioned is correct.
Let us assume that Phase_1 is the phase after the Initial Phase, where you activate your load. This phase could be a plastic or consolidation (and simultaneous loading) calculation, followed by a consolidation (min. EPP or DoC) calculation in Phase_2.

Thank you Mr.  Vasileios. 

The deformations from the plastic phase, will they affect the consolidation phase? For  Minimum excess pore pressures and Degree of consolidation.

Hi Jamal,

I'm not sure whether or not I understand your question correctly. However, I suspect that you mentioned deformations in terms of degree-of-consolidation. Although the degree-of-consolidation is officially defined in terms of target settlement over final settlement, in PLAXIS it is defined as the target minimum excess pore pressure over the maximum initial excess pore pressure p_max/p_max,initial.

Hi Jamal, 

From your question what I understood was you are asking whether the structural load is involved in the consolidation analysis or not. 

I share my thoughts regarding your question.

First excess pore pressure in the clay layers is formed due to the applied load and the deformation in the plastic phase is the compression, not a consolidation. So when you apply the load it is taken by the water and water is incompressible. After a certain time due to the loading water is gone out of the soil and the applied stresses are changed as the effective stress in the soil and this stress will do the deformation. 

So based on the applied loading in the plastic phase, amount of excess water pressure is produced in the soil and during U% or ePWP consolidation analysis phase the excess pore water pressure is reduced to the defined target pore water pressure and u can find the time required for the reduction of ePWP based on the consolidation analysis. 

At the conclusion, the amount of excess pore water pressure is generated based on the applied loading in the plastic phase. Let's say you are going to place a structure with 50kPa in the consolidated ground and you are going to do preloading before constructing the structure then you can do preloading more than 50 kPa to get the full consolidation and then can construct the structure.  

Thanks.

Thank you. This is what I was asking.