water pore pressure

Question

hello. I want to ask, previously at this time I was modeling soil improvement using the PVD method with preloading, but when I saw the pore water pressure output in the middle of the soft clay layer the result was like this. if it's like this why is my pore water pressure graph flat like this and how to solve it? thank you so much before

Vasileios Basas · Accepted Answer

Hi Randy, 
 It seems that Node 94399 is a post-calc node. Make sure that you have selected a pre-calc node and plot the same graph. 
 To select these Pre-calc nodes/stress points: 
 
 from the Input program, click the button for Select points for curves to start Output and
 
 click on a node (or stress point) 
 or use the search closest option by filling in the coordinates 
 
 Do not forget to click the Update button

Vasileios Basas · Answer

In FEM, the stresses and strains are first calculated at the stress points (Gauss points) and then extrapolated to nodal values (stress recovery). However, the extrapolation is not always perfect; therefore, the nodal values can differ from those on the Gaussian point. The extrapolation is affected primarily by the mesh density and gradient of stresses (how abruptly they change). As such, it is better to check stresses and strains directly at the source: the stress points.

water pore pressure

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