1D Wave propagation

Hi there,

I am working on a comparison of a 1D wave propagation and Deepsoil, but I am seeing some large discrepancies. I am modeling a 15m thick soil column of clay (HS Small). The "bedrock" layer is a 1m thick linear elastic material wit vs = 550 m/s. The issues I am seeing are the following

1) Comparing input motion at the compliant base versus the recorded motion at points C and B, it looks quite different.

• Point C is in the middle of the elastic layer (0.5m above compliant base), an I am seeing some filtering of the low periods. See attached plot comparison
• Point B is at the top of the linear elastic layer (1m above compliant base) and I am seeing high oscillations into the higher periods- see plot for comparisons

2) Comparison between DEEPSOIL and Plaxis:

• I used the same input parameters and extracted the damping parameters from the deepsoil curves.
• I am seeing a shift in the period where the response is amplified. Plaxis shows amplification around 0.6 second and deeposil around 1.1 seconds. Below is the response plot.

My questions are:

1) Is it normal to see such a change in the input motion within the linear elastic layer? If no, what is the solution to fix this?
2) Is it normal to see such a discrepancy between deepsoil response and Plaxis? If no, what are your recommendations to fix this? I have consulted with the reference manual and the examples provided here (https://communities.bentley.com/products/geotech-analysis/w/wiki/45528/one-dimensional-wave-propagation )and didn't see anywhere the answers I am looking for.

thank you