I have a case study of a lateral static pile load test.
how can I simulate a lateral static pile load test in Plaxis 3D?
I use a mesh volume to resemble the concrete pile with concrete properties of MC constitutive model.
What is the best method to simulate the loading-unloading behavior (Elastic-plastic behavior) (permanent deflection after unloading)of the concrete pile subjected to lateral pile load test (going with load to the peak of the first cycle then back again to zero, then to higher load in second cycle then to zero, etc.)
if i do the loading cycles as calculation phases (a new calculation phase for each load), i can reach to achieve a matching lateral deflection, but this gives very high moments which is too way far from the actual expected results.
Dear Mohamed,
You need to use pile volume element to simulate the concrete pile and assume it to behave in linear elastic. Simulate the soil using Mohr-Coulomb model with non linear elastic. The lateral load on the pile can be applied with the use of horizontal point load. In order to simulate the experimental test results in numerical model, first of all use appropriate scaling law from laboratory model scale to field model. The next step is verify you are assigning correct material properties in the analysis. The mesh density and mesh size also influencing on the final results. I suggest you to perform trail analysis by verifying with all parameters are correctly used in the model. All the best ..
Dear Prof. Karthigeyan
Thank you for your kind reply.
I understand that linear-elastic model doesn't give a chance for forming plastic deformations in the concrete pile, so I won't be able to model the loading unloading behavior accurately (model the behavior of all cycles in one model). I can easily use it as for each cycle as a separate model, but not for the whole static test with all loading-unloading behavior as attached.
Also I tried applying a point load on a volume element and I found it is not understood for PLAXIS to be applied to the whole volume but only to the specified point, so I apply the load in the form of stress (surface load) on the upper surface of the volume element.
All I want is to model all the cycles of the static load test with loading and unloading to give the same behavior as attached.
I believe a model that uses non-linear plastic behavior is required for concrete modeling.
Thanks for your concern
Mohamed Mohamed Mansour - Why do you think that the permanent deflection after unloading is due to pile plastic deformation? It is possible that the soil has undergone permanent deformations.
Concerning the unloading/reloading curves all together, you may do the following for the Static Load Test curve.
Create plastic calculation phases as follows:
Phase 1: Apply a lateral prescribed displacement of 18mm
Phase 2: Deactivate the lateral prescribed displacement
Phase 3: Apply a lateral prescribed displacement of 35mm
Phase 4: Deactivate the lateral prescribed displacement
Phase 5: Apply a prescribed displacement of 70mm
Phase 6: Deactivate the lateral prescribed displacement
Phase 7: Apply a prescribed displacement of 125mm
Phase 6: Deactivate the lateral prescribed displacement
Now you can plot reaction force (Fx) against Ux and you will have the loading/unloading cycles. You may have to adjust the pile and soil properties so that the computed load matches the experimental values.
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