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CFVR1612 - Active Pressure acting on surface elements

Active Pressure of a terrain acting on surface elements.

A terrain surrounds a structure made up of 8 nodes shell elements. The purpose of this example is to apply the equivalent loads of the terrain on a virtual model, made up of non-structural surface elements.
The structure is a half frame with inclined walls as shown in the figure, with a total height
The terrain is defined by a single soil material with the following parameters:

  • Friction angle between the ground and wall: 15º
  • Slope angle of the ground: 10º
  • Uniform surface load on the ground per unit of slope length: 0.1 Tn/m2
  • Ground level: 5.0 m measured from the bottom of the structure
  • Water table level: 3.0 m measured from the bottom of the structure
  • Porosity: 0.3
  • Dry specific weight 2.0 Tn/m3
  • Internal friction angle: 30º
Active pressure is applied.

Element types used in the model: SURF154

Needed CivilFEM Modules:
Geotechnical Module
Bridges and Civil Non Linearities Module
Advanced Prestressed Concrete Module

The example can be launched on an educational license.
KEYWORDS
Terrain


Model Statistics
Number of elements 2
Number of nodes 6
Number of civil materials 1
Number of cross sections 0
Number of shell vertices 0

Log file: CFVR1612.DAT


! DESCRUPTION: of 2.0 m.
  FINISH
  ~CFCLEAR,,1
  NomFile='CFVR1612'
  /TITLE, %NomFile%, Active Pressure acting on surface elements
  ~CFACTIV,GETC,Y ! Geotechnical module activation

! ---------------------------------------------------------------------------------
! Model definition
! ---------------------------------------------------------------------------------
! Civil Setup
~UNITS,,LENG,M
~UNITS,,TIME,S
~UNITS,,FORC,MP

/PREP7 ! Preprocessor
  ET,1,Surf154

  N,1,0,0
  N,2,0,1
  N,3,0.5774,2
  N,4,0,0,-1
  N,5,0,1,-1
  N,6,0.5774,2,-1
  E,1,2,5,4
  E,2,3,6,5
  /VIEW,1,-0.8,0.9,1.1
  EPLOT
  /IMAGE, SAVE, %NomFile%,BMP

  DELTA= 15        ! Friction angle between the ground and wall, in degrees
  BETA=  10        ! Slope angle of the ground, in degrees
  Q=      0.1      ! Uniform surface load on the ground per unit of slope length
  EAKCN=  0        ! Reference number of the coordinate system in which the ground is defined
  EAH=    5.0      ! Ground level next to the wall
  WKEY=   1        ! Code identifying the influence of the water
  WH=     3.0      ! Water Table
  ~CFMP,1,LIB,SOIL,,SW
  ~CFMP,1,SOIL    ,N       ,,0.3
  ~CFMP,1,SOIL    ,GAMD    ,,2.0
  ~CFMP,1,SOIL    ,PHIMCEFF,,30
  ~TERDEF,1,NEW,2,EAKCN,Y,EAH,BETA, Q, WKEY, WH, Terrain 1
  ~TERDEF,1,LAYER,1,1,1.0,0,CLMB,DELTA
  ~TERDEF,1,LAYER,2,1,2.0,0,CLMB,DELTA

  ~ETHSFE,1,ACT,1      ! Active Pressure

! ---------------------------------------------------------------------------------
! DATA CHECK
! ---------------------------------------------------------------------------------
! Data comparison number
  NComp = 8
  NComp_ch = 0

! Marix dim.
  *DIM,LABEL,CHAR,Ncomp,1
  *DIM,LABEL_CH,CHAR,Ncomp_ch,1
  *DIM,VALUE,,Ncomp,3
  *DIM,VALUE_CH,CHAR,Ncomp_ch,3
  *DIM,TOLER,,Ncomp,2

! Labels
! ---------------------------------------------------------------------------------
  LABEL(1) ='Pn1'
  LABEL(2) ='Pn2'
  LABEL(3) ='Fx1'
  LABEL(4) ='Fy1'
  LABEL(5) ='Fx2'
  LABEL(6) ='Fy2'
  LABEL(7) ='Fx3'
  LABEL(8) ='Fy3'

! Correct Values
  VALUE( 1,1)=  5.6517
  VALUE( 2,1)=  6.1115
  VALUE( 3,1)=  0.000
  VALUE( 4,1)= -0.1776
  VALUE( 5,1)= -0.1590
  VALUE( 6,1)= -0.4242
  VALUE( 7,1)= -0.1282
  VALUE( 8,1)= -0.2220

! Obtained values
  *GET,VALUE(1,2),ELEM,1,PRES,1
  *GET,VALUE(2,2),ELEM,2,PRES,1
  *GET,VALUE(3,2),NODE,1,F,FX
  *GET,VALUE(4,2),NODE,1,F,FY
  *GET,VALUE(5,2),NODE,2,F,FX
  *GET,VALUE(6,2),NODE,2,F,FY
  *GET,VALUE(7,2),NODE,3,F,FX
  *GET,VALUE(8,2),NODE,3,F,FY

! Warning and error tolerances
  *DO,I,1,NComp
    TOLER(I, 1)= 1E-3   $   TOLER(I, 2)= 1E-3
  *ENDDO

! ---------------------------------------------------------------------------------
! Results Comparison
! ---------------------------------------------------------------------------------
  COMPARA.MAC

Results

LabelTargetCivilFEMRatioTolerance
Pn1 5.6517 5.65171.000 0.001
Pn2 6.1115 6.11141.000 0.001
Fx1 0 00.000 0.001
Fy1 -0.1776 -0.177631.000 0.001
Fx2 -0.159 -0.159021.000 0.001
Fy2 -0.4242 -0.424181.000 0.001
Fx3 -0.1282 -0.128171.000 0.001
Fy3 -0.222 -0.221971.000 0.001


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