Marcus's Communities Activities

Hardening Soil Model Parameters

Marcus — Sun, 21 Nov 2021 12:05:13 GMT

Dear All

I have oedometer test data providing einit, Cc, Cs and also Multistage CIU triaxial data from which I have obtained c' phi'.

I am utilising the hardening soil model for settlement estimates of foundation loading.

My question is, do I need to adjust the default advanced value of 100kPa for pref? I have read some responses saying that it is just sigma'1 which I don't quite understand. Would this sigma'1 be the tangent to the oedometer load vs strain curve at a) my insitu effective vertical stress, b) insitu effective stress plus load or c) something else?

Thanks very much

Marcus

Modelling soil structure interfaces - retaining wall adjacent to slope

Marcus — Mon, 02 Nov 2020 04:48:55 GMT

Hello

I am trying to finalise a fully coupled analysis of a retaining wall with staged loading of an embankment behind.

My requirements are to review the factor of safety at the fully coupled final loading stage and also forces on the retaining wall and deflections (including a stability check).

The concrete retaining wall is being modelled as a linear elastic soil mass with modulus, unit weight and poissons ratio as appropriate for this material.

I understand that I need to create an interface element (and activate one loading applied by soil mass) to ensure the concrete wall acts independently of the soil behind. I note that depending on which direction i click along the boundary of the concrete wall and soil mass i get either a positive or negative interface. Does it matter which one I use and are there any other interface settings that need to be adjusted to model this realistically?

Also, how do I correctly review the normal, shear forces and deflections on and along the wall in areas of interest following the calculation? I'm assuming that it i select either a point or line section of the concrete immediately adjacent to the interface rather than on the interface itself?

Kind Regards

Marcus

Plaxis Factor of Safety Queries

Marcus — Mon, 15 Jun 2020 04:30:18 GMT

Good Afternoon

I have been using Plaxis 2D to carry out some Factor of Safety Analysis (FOS).

Two sections of the embankment have been considered in the analysis with an initial gravity loading applied with the full embankment (no staging) followed by the FOS calculation. As the soil is mixed (sandy clay), I am considering both drained and undrained cases for the embankment material with MC parameters and inputting the phreatic level along with estimated permeabilities. One of my sections gives very similar FOS results for both drained and undrained cases whilst the other does not (undrained approx. 0.2 less). This is with no change in parameters except changing the embankment from Undrained A to Drained.

Can I please get thoughts on what this might indicate? How do I settle on which FOS might apply?

Regards

Marcus

Ask A Question I

Mon, 15 Jun 2020 00:19:33 GMT

Ask a question in a forum.