Hi,
I'm trying to reproduce the results of a publication that deals with pile test loads. Here, a displacement load is applied to the pile. However, the simulations fail depending on the phase sequence. I have tried two different approaches. First, the applied displacement on the pile was increased phase by phase. After the last phase the displacement should be 0.07m. With this approach the simulation fails in the second last phase at a displacement of 0.017m with the error message "Load advancement procedure fails. [Error code: 103]". Second I've tried to model the whole displacement in one single phase. Here the simulation runs until a displacement of 0.04m and then fails. In both approaches the resulting force starts to oscillate right before the simulation stops. In my opinion the simulation should stop at the same displacement or am I wrong? What is the difference between the two approaches and how can I reach the maximum applied displacement? I've also tried different meshes and the coarser the mesh the more likely it is that the simulation will reach the maximum displacement of 0.07m. The simulations were performed using Plaxis 2019.Enclosed the model setup with the different approaches.
.
##~ running Plaxis2DXInput.exe 2019.0.0.0 _initializerectangular SoilContour 0 0 9 15 _setproperties "Title" "Pfahlbelastung" "Comments" "" "UnitForce" "kN" "UnitLength" "m" "UnitTime" "day" "UnitTemperature" "K" "UnitEnergy" "kJ" "UnitPower" "kW" "WaterWeight" 10 "ReferenceTemperature" 293.15 "LiquidSpecificHeatCapacity" 4181.3 "LiquidThermalConductivity" 0.0006 "LiquidLatentHeat" 334000 "LiquidThermalExpansion" 0.00021 "LiquidTemperature" 293.15 "IceSpecificHeatCapacity" 2108 "IceThermalConductivity" 0.00222 "IceThermalExpansion" 5E-5 "VapourSpecificHeatCapacity" 1930 "VapourThermalConductivity" 2.5E-5 "VapourSpecificGasConstant" 461.5 "UseTemperatureDepWaterPropsTable" False "ModelType" "Axisymmetry" "ElementType" "15-Noded" _gotostructures _polygon (0 0) (9 0) (9 15) (0 15) _soilmat "Comments" "" "MaterialName" "Steifer Ton HS" "Colour" 10676870 "MaterialNumber" 2 "SoilModel" 3 "UserDefinedIndex" 0 "DrainageType" 0 "DilatancyCutOff" False "UndrainedBehaviour" 0 "InterfaceStrength" 0 "InterfaceStiffness" 0 "ConsiderGapClosure" True "K0PrimaryIsK0Secondary" True "K0Determination" 0 "SolidThermalExpansion" 1 "UnfrozenWaterContent" 0 "TableUnfrozenWaterContent" "[]" "CrossPermeability" 0 "DefaultValuesAdvanced" True "DataSetFlow" 0 "ModelFlow" 0 "UDModelFlow" 0 "SoilTypeFlow" 0 "LowerUpper" 0 "UsdaSoilType" 0 "StaringUpperSoilType" 0 "StaringLowerSoilType" 0 "M50" 0 "UseDefaultsFlow" 0 "TablePsiPermSat" "[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]" "SplinePsiPerm" "[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]" "SplinePsiSat" "[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]" "UseAlternatives" False "TensionCutOff" True "einit" 0.499999999999999 "emin" 0 "emax" 999 "SkemptonB" 0.986622073578595 "KwRefN" 3687500 "VolumetricSpecificStorage" 2.71186440677966E-6 "SolidThermalExpansionTotal" 0 "DrainageConductivity" 0 "EurRef" 90000 "ErefOed50" 0.733333333333333 "ErefUr50" 2 "Cc" 0.0104545454545454 "Cs" 0.00345 37500 0.2 20 20 0 0 0 0 20 20 0 0 1 0 0 0 0 0 0 0.333333333333333 0 0.999 0 0 0 0 1.0000000000000000E+015 0.495 0 0 0.55249663172925 1.46502579016215 0 0.5 100 67201.2715860466 0.9 33000 0.657979856674331 45000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0.8 0.8 1 0 2 -1.06 -2.37 0 0 10000 1 0.0620347394540943 3.83 1.3774 1.25 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 10 13 77 0 0 0 0 0 0 0 _soilmat "Comments" "" "MaterialName" "Pfahl" "Colour" 10283244 "MaterialNumber" 0 "SoilModel" 1 "UserDefinedIndex" 0 "DrainageType" 0 "DilatancyCutOff" False "UndrainedBehaviour" 0 "InterfaceStrength" 0 "InterfaceStiffness" 0 "ConsiderGapClosure" True "K0PrimaryIsK0Secondary" True "K0Determination" 1 "SolidThermalExpansion" 1 "UnfrozenWaterContent" 0 "TableUnfrozenWaterContent" "[]" "CrossPermeability" 0 "DefaultValuesAdvanced" True "DataSetFlow" 0 "ModelFlow" 0 "UDModelFlow" 0 "SoilTypeFlow" 0 "LowerUpper" 0 "UsdaSoilType" 0 "StaringUpperSoilType" 0 "StaringLowerSoilType" 0 "M50" 0 "UseDefaultsFlow" 0 "TablePsiPermSat" "[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]" "SplinePsiPerm" "[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]" "SplinePsiSat" "[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]" "einit" 0.5 "emin" 0 "emax" 998.999999999999 "Dinter" 0 "SkemptonB" 0.986622073578595 "KwRefN" 1229166666.66667 "VolumetricSpecificStorage" 8.13559322033899E-9 "SolidThermalExpansionTotal" 0 "DrainageConductivity" 0 "Eref" 30000000 "Eoed" 33333333.3333333 "Vs" 2214.72345903501 "Vp" 3616.62826400503 "Einc" 0 12500000 0.2 0 0 0 0 0 0 25 25 0 0 1 0 0 0 0 0 0 0.333333333333333 0 0.999 0 0 0 0 1.0000000000000000E+015 0.495 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0.5 0.5 1 0 0 -1.06 -2.37 0 0 10000 1 0.0620347394540943 3.83 1.3774 1.25 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 10 13 77 0 0 0 0 0 0 0 _setmaterial (Soil_1) SteiferTonHS _line 3 15 3 3 _line 3 3 0 3 _line 0.65 15 0.65 5.5 _line 0.65 5.5 0 5.5 _linedispl 0 15 0.65 15 _mergeequivalents Geometry _gotomesh _set Line_5_1.CoarsenessFactor 0.1 _set Line_4_1.CoarsenessFactor 0.1 _set Polygon_1_1.CoarsenessFactor 0.1 _set Polygon_1_2.CoarsenessFactor 0.1 _mesh 0.07998 #coarse _selectmeshpoints /Output acp "Node" Soil_1_1 (0 15) /Output update _gotostages _activate Soils InitialPhase _phase InitialPhase _set Soil_1_1.Material Phase_1 Pfahl _phase Phase_1 _set Phase_2.Deform.ResetDisplacementsToZero True _activate (LineDisplacement_1_1) Phase_2 _set LineDisplacement_1_1.uy_start Phase_2 -0.001 _phase Phase_2 _set LineDisplacement_1_1.uy_start Phase_3 -0.002 _phase Phase_3 _set LineDisplacement_1_1.uy_start Phase_4 -0.004 _phase Phase_4 _set LineDisplacement_1_1.uy_start Phase_5 -0.008 _phase Phase_5 _set LineDisplacement_1_1.uy_start Phase_6 -0.016 _phase Phase_6 _set LineDisplacement_1_1.uy_start Phase_7 -0.03 _phase Phase_7 _set LineDisplacement_1_1.uy_start Phase_8 -0.07 _phase Phase_1 _activate (LineDisplacement_1_1) Phase_9 _set LineDisplacement_1_1.uy_start Phase_9 -0.07
Dear Siegfried,
The activation of (self-)weight and loads in a Plastic phase, Consolidation phase and Fully coupled flow-deformation analysis is considered to be an out-of-balance force. In order to solve this out-of-balance, the calculation will use a linear relationship with the ΣMstage multiplier to activate these new loads. This is explained in more detail in the following article: https://communities.bentley.com/products/geotech-analysis/w/plaxis-soilvision-wiki/45973/load-activation-in-time
That means that due to the different out-of-balance to be solved in each model the solution can be slightly different.
The error you encountered, according to our reference manual, mentions that there are numerical problems detected. You need to inspect the input data and the calculation results in Output to evaluate why it fails.
In general, in some cases, it helps to edit the numerical control parameters and edit the max load fraction per step to a lower value. You can check more details about these parameters and the impact on the analysis in our reference manual.
If the above does not help identify the reason for this problem, please submit a service request.
Then, one of our support engineers can help you in detail: https://apps.bentley.com/srmanager/ProductSupport
Answer Verified By: Siegfried Galkin