Drucker-Prager Constitutive Model (LAWS 10, 21 and 81)

Drucker-Prager (LAW10 and LAW21)

For materials, like soils and rocks, the frictional and dilatational effects are significant. In these materials, the plastic behavior depends on the pressure as the internal friction is proportional to the normal force.

Furthermore, for frictional materials, associative plasticity laws, in which the plastic flow is normal to the yield surface, are often inappropriate. Drucker-Prager 1 yield criterion uses a modified von Mises yield criteria to incorporate the effects of pressure for massive structures:(1) F = J 2 ( A 0 + A 1 P + A 2 P 2 ) MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOraiabg2 da9iaadQeadaWgaaWcbaGaaGOmaaqabaGccqGHsisldaqadaqaaiaa dgeadaWgaaWcbaGaaGimaaqabaGccqGHRaWkcaWGbbWaaSbaaSqaai aaigdaaeqaaOGaamiuaiabgUcaRiaadgeadaWgaaWcbaGaaGOmaaqa baGccaWGqbWaaWbaaSqabeaacaaIYaaaaaGccaGLOaGaayzkaaaaaa@4584@
Where,
J 2 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOsamaaBa aaleaacaaIYaaabeaaaaa@37AD@
Second invariant of deviatoric stress J 2 = 1 2 s i j s i j MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbwvMCKf MBHbqefqvATv2CG4uz3bIuV1wyUbqedmvETj2BSbqefm0B1jxALjhi ov2DaebbnrfifHhDYfgasaacH8srps0lbbf9q8WrFfeuY=Hhbbf9v8 qqaqFr0xc9pk0xbba9q8WqFfea0=yr0RYxir=Jbba9q8aq0=yq=He9 q8qqQ8frFve9Fve9Ff0dmeaacaGacmGadaWaaiqacaabaiaafaaake aacaWGkbWaaSbaaSqaaiaaikdaaeqaaOGaeyypa0ZaaSaaaeaacaaI XaaabaGaaGOmaaaacaWGZbWaaSbaaSqaaiaadMgacaWGQbaabeaaki aadohadaWgaaWcbaGaamyAaiaadQgaaeqaaaaa@4331@
P MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiuaaaa@36CB@
Pressure
A 0 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyqamaaBa aaleaacaaIWaaabeaaaaa@37A2@ , A 1 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyqamaaBa aaleaacaaIXaaabeaaaaa@37A3@ , A 2 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyqamaaBa aaleaacaaIXaaabeaaaaa@37A3@
Material coefficients

図 1 shows 式 1 in the plane of J 2 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaOaaaeaaca WGkbWaaSbaaSqaaiaaikdaaeqaaaqabaaaaa@37BD@ and P MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiuaaaa@36CB@ . The criterion expressed in the space of principal stresses represents a revolutionary surface with an axis parallel to the trisecting of the space as shown in 図 2. This representation is in contrast with the von Mises criteria where yield criterion has a cylindrical shape. Drucker-Prager criterion is a simple approach to model the materials with internal friction because of the symmetry of the revolution surface and the continuity in variation of normal to the yield surface.

For LAW10 pressure evaluation for EOS is described with /EOS/COMPATION.

The pressure in the material is determined in function of volumetric strain for loading phase:(2) P = f ( μ )

for loading d μ > 0

Where, f MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOzaaaa@36E1@ is a user-defined (LAW21) or a cubic polynomial function (LAW10). For unloading phase, if the volumetric strain has a negative value, a linear relation is defined as:(3) P = C 1 μ

for unloading d μ < 0 and μ < 0

For unloading with a positive volumetric strain, another linear function may be used:(4) P = B μ

for unloading d μ < 0 and μ > 0

In Radioss extended Drucker-Prager model is used in LAW10 and LAW21. Neither of these laws can reproduce the mono-dimensional behavior. In addition, no viscous effect is taken into account.


図 1. Yield Criteria in the Plane of J 2 and P


図 2. Drucker-Prager Yield Criteria in Space of Principal Stresses


図 3. Material Pressure Variation in Function of Volumetric Strain

Drucker-Prager Constitutive Model with Cap (LAW81)

Yield Surface

The Drucker-Prager yield surface is:(5) F = q r c ( p ) ( p tan β + c ) = 0 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOraiabg2 da9iaadghacqGHsislciGGYbWaaSbaaSqaaiaacogaaeqaaOWaaeWa aeaacaWGWbaacaGLOaGaayzkaaGaeyyXIC9aaeWaaeaacaWGWbGaci iDaiaacggacaGGUbGaeqOSdiMaey4kaSIaam4yaaGaayjkaiaawMca aiabg2da9iaaicdaaaa@4B01@


図 4.
Cap hardening considered in this material law in p a < p < p b MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCamaaBa aaleaacaWGHbaabeaakiabgYda8iaadchacqGH8aapcaWGWbWaaSba aSqaaiaadkgaaeqaaaaa@3D0C@ is described with:(6) r c ( p )= 1 ( p p a p b p a ) 2 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaciOCamaaBa aaleaacaGGJbaabeaakmaabmaabaGaamiCaaGaayjkaiaawMcaaiab g2da9maakaaabaGaaGymaiabgkHiTmaabmaabaWaaSaaaeaacaWGWb GaeyOeI0IaamiCamaaBaaaleaacaWGHbaabeaaaOqaaiaadchadaWg aaWcbaGaamOyaaqabaGccqGHsislcaWGWbWaaSbaaSqaaiaadggaae qaaaaaaOGaayjkaiaawMcaamaaCaaaleqabaGaaGOmaaaaaeqaaaaa @48CC@
In lower compression or tension p p a MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCaiabgs MiJkaadchadaWgaaWcbaGaamyyaaqabaaaaa@3AA7@ , then linear yield surface will be considered with:(7) r c ( p ) = 1 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaciOCamaaBa aaleaacaGGJbaabeaakmaabmaabaGaamiCaaGaayjkaiaawMcaaiab g2da9iaaigdaaaa@3C4A@
Where,
q MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyCaaaa@36EC@
von Mises stress
q 2 = 3 J 2 = 3 2 s i j 2 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyCamaaCa aaleqabaGaaGOmaaaakiabg2da9iaaiodacaWGkbWaaSbaaSqaaiaa ikdaaeqaaOGaeyypa0ZaaSaaaeaacaaIZaaabaGaaGOmaaaacaWGZb WaaSbaaSqaaiaadMgacaWGQbaabeaakmaaCaaaleqabaGaaGOmaaaa aaa@41E6@
p MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCaaaa@36EB@
Pressure
p = 1 3 σ i j = 1 3 I 1 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCaiabg2 da9iabgkHiTmaalaaabaGaaGymaaqaaiaaiodaaaGaeq4Wdm3aaSba aSqaaiaadMgacaWGQbaabeaakiabg2da9iabgkHiTmaalaaabaGaaG ymaaqaaiaaiodaaaGaamysamaaBaaaleaacaaIXaaabeaaaaa@436C@
s i j MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4CamaaBa aaleaacaWGPbGaamOAaaqabaaaaa@38F7@
Deviatoric stress
s i j = σ i j + p δ i j MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4CamaaBa aaleaacaWGPbGaamOAaaqabaGccqGH9aqpcqaHdpWCdaWgaaWcbaGa amyAaiaadQgaaeqaaOGaey4kaSIaamiCaiabes7aKnaaDaaaleaaca WGPbaabaGaamOAaaaaaaa@4363@
c MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSbaaSqaai aacogaaeqaaaaa@3709@
Cohesion
β
Friction angle
p 0 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCamaaBa aaleaacaaIWaaabeaaaaa@37D1@
Pressure value
F p ( p 0 )=0 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSaaaeaacq GHciITcaWGgbaabaGaeyOaIyRaamiCaaaadaqadaqaaiaadchadaWg aaWcbaGaaGimaaqabaaakiaawIcacaGLPaaacqGH9aqpcaaIWaaaaa@3FC0@

Plastic Flow

Plastic flow is governed by the non-associated flow potential G MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4raaaa@36C2@ defined as:

If p p a MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCaiabgs MiJkaadchadaWgaaWcbaGaamyyaaqabaaaaa@3AA7@ (8) G = q p tan ψ = 0 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4raiabg2 da9iaadghacqGHsislcaWGWbGaeyyXICTaciiDaiaacggacaGGUbGa eqiYdKNaeyypa0JaaGimaaaa@4349@
If p a < p p 0 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCamaaBa aaleaacaWGHbaabeaakiabgYda8iaadchacqGHKjYOcaWGWbWaaSba aSqaaiaaicdaaeqaaaaa@3D90@ (9) G = q tan ψ ( p ( p p a ) 2 2 ( p 0 p a ) ) = 0 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4raiabg2 da9iaadghacqGHsislciGG0bGaaiyyaiaac6gacqaHipqEdaqadaqa aiaadchacqGHsisldaWcaaqaamaabmaabaGaamiCaiabgkHiTiaadc hadaWgaaWcbaGaamyyaaqabaaakiaawIcacaGLPaaadaahaaWcbeqa aiaaikdaaaaakeaacaaIYaWaaeWaaeaacaWGWbWaaSbaaSqaaiaaic daaeqaaOGaeyOeI0IaamiCamaaBaaaleaacaWGHbaabeaaaOGaayjk aiaawMcaaaaaaiaawIcacaGLPaaacqGH9aqpcaaIWaaaaa@511C@
If p > p 0 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCaiabg6 da+iaadchadaWgaaWcbaGaaGimaaqabaaaaa@39CE@ (example, the flow becomes associated on the cap)(10) G=F MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4raiabg2 da9iaadAeaaaa@3893@

The plastic potential is continuous as you have G p ( p 0 ) = F p ( p 0 ) = 0 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSaaaeaacq GHciITcaWGhbaabaGaeyOaIyRaamiCaaaadaqadaqaaiaadchadaWg aaWcbaGaaGimaaqabaaakiaawIcacaGLPaaacqGH9aqpdaWcaaqaai abgkGi2kaadAeaaeaacqGHciITcaWGWbaaamaabmaabaGaamiCamaa BaaaleaacaaIWaaabeaaaOGaayjkaiaawMcaaiabg2da9iaaicdaaa a@48D1@ .

By definition the plastic flow is normal to the flow potential.(11) d ε ij p =dΛ G σ ij MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamizaiabew 7aLnaaDaaaleaacaWGPbGaamOAaaqaaiaadchaaaGccqGH9aqpcaWG KbGaeu4MdWKaeyyXIC9aaSaaaeaacqGHciITcaWGhbaabaGaeyOaIy Raeq4Wdm3aaSbaaSqaaiaadMgacaWGQbaabeaaaaaaaa@48B1@

The scalar d Λ MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamizaiabfU 5ambaa@3854@ will be determined in order to satisfy consistency and experimental hardening/softening.

Hardening/Softening

The cap is defined by only one parameter p b MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCamaaBa aaleaacaWGIbaabeaaaaa@37FE@ , assume that p a MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCamaaBa aaleaacaWGHbaabeaaaaa@37FD@ evolves according to:(12) p a p b = p a0 p b0 =α MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSaaaeaaca WGWbWaaSbaaSqaaiaadggaaeqaaaGcbaGaamiCamaaBaaaleaacaWG IbaabeaaaaGccqGH9aqpdaWcaaqaaiaadchadaWgaaWcbaGaamyyai aaicdaaeqaaaGcbaGaamiCamaaBaaaleaacaWGIbGaaGimaaqabaaa aOGaeyypa0JaeqySdegaaa@437B@
Where,
p a 0 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCamaaBa aaleaacaWGHbGaaGimaaqabaaaaa@38B7@ and p b 0 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCamaaBa aaleaacaWGHbGaaGimaaqabaaaaa@38B7@
Initial value of p a MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCamaaBa aaleaacaWGHbaabeaaaaa@37FD@ and p b MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCamaaBa aaleaacaWGIbaabeaaaaa@37FE@
The evolution of p b MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCamaaBa aaleaacaWGIbaabeaaaaa@37FE@ depends on ε v p = ε i i p MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqyTdu2aa0 baaSqaaiaadAhaaeaacaWGWbaaaOGaeyypa0JaeyOeI0IaeqyTdu2a a0baaSqaaiaadMgacaWGPbaabaGaamiCaaaaaaa@405C@ via a curve given in input fct_IDpb.
注: The same sign conversion for ε v p MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqyTdu2aa0 baaSqaaiaadAhaaeaacaWGWbaaaaaa@39BA@ and p b MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCamaaBa aaleaacaWGIbaabeaaaaa@37FE@ , which is positive in compression is considered.
  • Shear yielding has an effect on p b MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCamaaBa aaleaacaWGIbaabeaaaaa@37FE@ , which depends on the possible dilantancy imposed by the flow rule. An option to prevent this phenomenon is provided, for example, for rocks (cap softening deactivation flag Isoft).
  • p a MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCamaaBa aaleaacaWGHbaabeaaaaa@37FD@ is derived from p b MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCamaaBa aaleaacaWGIbaabeaaaaa@37FE@ via 式 12
  • If softening is allowed, the condition p a > 0 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCamaaBa aaleaacaWGHbaabeaakiabg6da+iaaicdaaaa@39C9@ is imposed, otherwise, d ε v p 0 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamizaiabew 7aLnaaDaaaleaacaWG2baabaGaamiCaaaakiabgwMiZkaaicdaaaa@3D2D@

Derive Stress-Strain Relationships

Considering bulk and shear moduli K MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4saaaa@36C6@ and μ , write the relationship between stress and elastic strain deviatoric tensors and and between pressure and volumetric strain and its plastic component.(13) d s i j = 2 μ ( d e i j d e i j p ) MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamizaiaado hadaWgaaWcbaGaamyAaiaadQgaaeqaaOGaeyypa0JaaGOmaiabeY7a TnaabmaabaGaamizaiaadwgadaWgaaWcbaGaamyAaiaadQgaaeqaaO GaeyOeI0IaamizaiaadwgadaqhaaWcbaGaamyAaiaadQgaaeaacaWG WbaaaaGccaGLOaGaayzkaaaaaa@489A@ (14) dp=K( d ε ii d ε ii p )=K( d ε ii d ε ii p ) MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamizaiaadc hacqGH9aqpcqGHsislcaWGlbWaaeWaaeaacaWGKbGaeqyTdu2aaSba aSqaaiaadMgacaWGPbaabeaakiabgkHiTiaadsgacqaH1oqzdaqhaa WcbaGaamyAaiaadMgaaeaacaWGWbaaaaGccaGLOaGaayzkaaGaeyyp a0JaeyOeI0Iaam4samaabmaabaGaamizaiabew7aLnaaBaaaleaaca WGPbGaamyAaaqabaGccqGHsislcaWGKbGaeqyTdu2aa0baaSqaaiaa dMgacaWGPbaabaGaamiCaaaaaOGaayjkaiaawMcaaaaa@56BA@
Note that,(15) G σ i j = 1 3 G p δ i j + 3 2 q s i j MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSaaaeaacq GHciITcaWGhbaabaGaeyOaIyRaeq4Wdm3aaSbaaSqaaiaadMgacaWG QbaabeaaaaGccqGH9aqpcqGHsisldaWcaaqaaiaaigdaaeaacaaIZa aaamaalaaabaGaeyOaIyRaam4raaqaaiabgkGi2kaadchaaaGaeqiT dq2aa0baaSqaaiaadMgaaeaacaWGQbaaaOGaey4kaSYaaSaaaeaaca aIZaaabaGaaGOmaiaadghaaaGaam4CamaaBaaaleaacaWGPbGaamOA aaqabaaaaa@4FA7@ (16) F s ij = G s ij = 3 2q s ij MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSaaaeaacq GHciITcaWGgbaabaGaeyOaIyRaam4CamaaBaaaleaacaWGPbGaamOA aaqabaaaaOGaeyypa0ZaaSaaaeaacqGHciITcaWGhbaabaGaeyOaIy Raam4CamaaBaaaleaacaWGPbGaamOAaaqabaaaaOGaeyypa0ZaaSaa aeaacaaIZaaabaGaaGOmaiaadghaaaGaam4CamaaBaaaleaacaWGPb GaamOAaaqabaaaaa@4AE7@
You can relate the increment of the plastic volumetric strain d ε v p MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamizaiabew 7aLnaaDaaaleaacaWG2baabaGaamiCaaaaaaa@3AA3@ and the equivalent plastic strain d ε d p MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamizaiabew 7aLnaaDaaaleaacaWG2baabaGaamiCaaaaaaa@3AA3@ and d Λ MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamizaiabfU 5ambaa@3854@ .(17) d ε v p =dΛ G p MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamizaiabew 7aLnaaDaaaleaacaWG2baabaGaamiCaaaakiabg2da9iaadsgacqqH BoatdaWcaaqaaiabgkGi2kaadEeaaeaacqGHciITcaWGWbaaaaaa@42AE@

and d ε d p = d Λ G q MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamizaiabew 7aLnaaDaaaleaacaWGKbaabaGaamiCaaaakiabg2da9iaadsgacqqH BoatdaWcaaqaaiabgkGi2kaadEeaaeaacqGHciITcaWGXbaaaaaa@429D@ with G q = 1 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSaaaeaacq GHciITcaWGhbaabaGaeyOaIyRaamyCaaaacqGH9aqpcaaIXaaaaa@3C55@ .

and solving for d Λ MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamizaiabfU 5ambaa@3854@ from 式 11, 式 14, 式 16 and 式 17, you obtain,(18) d Λ = 1 h ( F s i j 2 μ d e i j F p K d ε i i ) MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamizaiabfU 5amjabg2da9maalaaabaGaaGymaaqaaiaadIgaaaWaaeWaaeaadaWc aaqaaiabgkGi2kaadAeaaeaacqGHciITcaWGZbWaaSbaaSqaaiaadM gacaWGQbaabeaaaaGccaaIYaGaeqiVd0MaamizaiaadwgadaWgaaWc baGaamyAaiaadQgaaeqaaOGaeyOeI0YaaSaaaeaacqGHciITcaWGgb aabaGaeyOaIyRaamiCaaaacaWGlbGaamizaiabew7aLnaaBaaaleaa caWGPbGaamyAaaqabaaakiaawIcacaGLPaaaaaa@54A0@

With h=3μ+K F p G p F c dc d ε d p G p F p b d p b d ε v p MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiAaiabg2 da9iaaiodacqaH8oqBcqGHRaWkcaWGlbWaaSaaaeaacqGHciITcaWG gbaabaGaeyOaIyRaamiCaaaadaWcaaqaaiabgkGi2kaadEeaaeaacq GHciITcaWGWbaaaiabgkHiTmaalaaabaGaeyOaIyRaamOraaqaaiab gkGi2kaadogaaaWaaSaaaeaacaWGKbGaam4yaaqaaiaadsgacqaH1o qzdaqhaaWcbaGaamizaaqaaiaadchaaaaaaOGaeyOeI0YaaSaaaeaa cqGHciITcaWGhbaabaGaeyOaIyRaamiCaaaadaWcaaqaaiabgkGi2k aadAeaaeaacqGHciITcaWGWbWaaSbaaSqaaiaadkgaaeqaaaaakmaa laaabaGaamizaiaadchadaWgaaWcbaGaamOyaaqabaaakeaacaWGKb GaeqyTdu2aa0baaSqaaiaadAhaaeaacaWGWbaaaaaaaaa@6444@

You can then compute all terms in 式 18.

If p p a MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCaiabgs MiJkaadchadaWgaaWcbaGaamyyaaqabaaaaa@3AA7@ , then F p = tan β MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSaaaeaacq GHciITcaWGgbaabaGaeyOaIyRaamiCaaaacqGH9aqpcqGHsislciGG 0bGaaiyyaiaac6gacqaHYoGyaaa@40F7@ , F c = 1 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSaaaeaacq GHciITcaWGgbaabaGaeyOaIyRaam4yaaaacqGH9aqpcqGHsislcaaI Xaaaaa@3D33@ , F p b = 0 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSaaaeaacq GHciITcaWGgbaabaGaeyOaIyRaamiCamaaBaaaleaacaWGIbaabeaa aaGccqGH9aqpcaaIWaaaaa@3D6F@ .

If p p a MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCaiabgw MiZkaadchadaWgaaWcbaGaamyyaaqabaaaaa@3AB8@ , then (19) F p = ( tan β r c + d r c d p ( p tan β + c ) ) MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSaaaeaacq GHciITcaWGgbaabaGaeyOaIyRaamiCaaaacqGH9aqpcqGHsisldaqa daqaaiGacshacaGGHbGaaiOBaiabek7aIjaadkhadaWgaaWcbaGaam 4yaaqabaGccqGHRaWkdaWcaaqaaiaadsgacaWGYbWaaSbaaSqaaiaa dogaaeqaaaGcbaGaamizaiaadchaaaWaaeWaaeaacaWGWbGaciiDai aacggacaGGUbGaeqOSdiMaey4kaSIaam4yaaGaayjkaiaawMcaaaGa ayjkaiaawMcaaaaa@531D@

F c = r c ( p ) MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSaaaeaacq GHciITcaWGgbaabaGaeyOaIyRaam4yaaaacqGH9aqpcqGHsislcaWG YbWaaSbaaSqaaiaadogaaeqaaOWaaeWaaeaacaWGWbaacaGLOaGaay zkaaaaaa@410B@

and F p b = p( p p a ) r c p b ( p b p a ) 2 ( ptanβ+c ) MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSaaaeaacq GHciITcaWGgbaabaGaeyOaIyRaamiCamaaBaaaleaacaWGIbaabeaa aaGccqGH9aqpdaWcaaqaaiabgkHiTiaadchadaqadaqaaiaadchacq GHsislcaWGWbWaaSbaaSqaaiaadggaaeqaaaGccaGLOaGaayzkaaaa baGaamOCamaaBaaaleaacaWGJbaabeaakiaadchadaWgaaWcbaGaam OyaaqabaGcdaqadaqaaiaadchadaWgaaWcbaGaamOyaaqabaGccqGH sislcaWGWbWaaSbaaSqaaiaadggaaeqaaaGccaGLOaGaayzkaaWaaW baaSqabeaacaaIYaaaaaaakmaabmaabaGaamiCaiGacshacaGGHbGa aiOBaiabek7aIjabgUcaRiaadogaaiaawIcacaGLPaaaaaa@5890@

If p p a MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCaiabgs MiJkaadchadaWgaaWcbaGaamyyaaqabaaaaa@3AA7@ , then G p =tanψ MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSaaaeaacq GHciITcaWGhbaabaGaeyOaIyRaamiCaaaacqGH9aqpcqGHsislciGG 0bGaaiyyaiaac6gacqaHipqEaaa@4125@

If p a p p 0 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCamaaBa aaleaacaWGHbaabeaakiabgsMiJkaadchacqGHKjYOcaWGWbWaaSba aSqaaiaaicdaaeqaaaaa@3E41@ , then (20) G p =tanψ ( p 0 p ) ( p 0 p a ) MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSaaaeaacq GHciITcaWGhbaabaGaeyOaIyRaamiCaaaacqGH9aqpcqGHsislciGG 0bGaaiyyaiaac6gacqaHipqEdaWcaaqaamaabmaabaGaamiCamaaBa aaleaacaaIWaaabeaakiabgkHiTiaadchaaiaawIcacaGLPaaaaeaa daqadaqaaiaadchadaWgaaWcbaGaaGimaaqabaGccqGHsislcaWGWb WaaSbaaSqaaiaadggaaeqaaaGccaGLOaGaayzkaaaaaaaa@4CF1@

If p p 0 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCaiabgw MiZkaadchadaWgaaWcbaGaaGimaaqabaaaaa@3A8C@ , then F p = G p MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSaaaeaacq GHciITcaWGgbaabaGaeyOaIyRaamiCaaaacqGH9aqpdaWcaaqaaiab gkGi2kaadEeaaeaacqGHciITcaWGWbaaaaaa@4035@

Finally, d q d p = 0 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSaaaeaaca WGKbGaamyCaaqaaiaadsgacaWGWbaaaiabg2da9iaaicdaaaa@3B83@ gives(21) p 0 = p a + ( p a tan β + c ) + ( p a tan β + c ) 2 + 8 [ tan β ( p b p a ) ] 2 4 tan β MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCamaaBa aaleaacaaIWaaabeaakiabg2da9iaadchadaWgaaWcbaGaamyyaaqa baGccqGHRaWkdaWcaaqaaiabgkHiTmaabmaabaGaamiCamaaBaaale aacaWGHbaabeaakiGacshacaGGHbGaaiOBaiabek7aIjabgUcaRiaa dogaaiaawIcacaGLPaaacqGHRaWkdaGcaaqaamaabmaabaGaamiCam aaBaaaleaacaWGHbaabeaakiGacshacaGGHbGaaiOBaiabek7aIjab gUcaRiaadogaaiaawIcacaGLPaaadaahaaWcbeqaaiaaikdaaaGccq GHRaWkcaaI4aWaamWaaeaaciGG0bGaaiyyaiaac6gacqaHYoGydaqa daqaaiaadchadaWgaaWcbaGaamOyaaqabaGccqGHsislcaWGWbWaaS baaSqaaiaadggaaeqaaaGccaGLOaGaayzkaaaacaGLBbGaayzxaaWa aWbaaSqabeaacaaIYaaaaaqabaaakeaacaaI0aGaciiDaiaacggaca GGUbGaeqOSdigaaaaa@6726@

When p < p 0 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCaiabgY da8iaadchadaWgaaWcbaGaaGimaaqabaaaaa@39CA@ and G p < 0 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSaaaeaacq GHciITcaWGhbaabaGaeyOaIyRaamiCaaaacqGH8aapcaaIWaaaaa@3C51@ leads to softening of the cap. If the no-softening cap flag is set, the last term in 式 14 is irrelevant. To achieve this, set F p b = 0 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSaaaeaacq GHciITcaWGgbaabaGaeyOaIyRaamiCamaaBaaaleaacaWGIbaabeaa aaGccqGH9aqpcaaIWaaaaa@3D6F@ and impose on the hardening parameter d ε v p MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamizaiabew 7aLnaaDaaaleaacaWG2baabaGaamiCaaaaaaa@3AA3@ not decrease, although there is some volumetric plastic flow d ε v p MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamizaiabew 7aLnaaDaaaleaacaWG2baabaGaamiCaaaaaaa@3AA3@ .

For p p b MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCaiabgk ziUkaadchadaWgaaWcbaGaamOyaaqabaaaaa@3AE0@ , d r c d p MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSaaaeaaca WGKbGaamOCamaaBaaaleaacaWGJbaabeaaaOqaaiaadsgacaWGWbaa aiabgkziUkabg6HiLcaa@3E40@ , d Λ MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamizaiabfU 5amjabgkziUkabg6HiLcaa@3BB2@ , so that d ε v p MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamizaiabew 7aLnaaDaaaleaacaWG2baabaGaamiCaaaaaaa@3AA3@ is undetermined in 式 17.

In this case, a special treatment needs to be performed; at first order, the deviatoric terms are neglected.(22)
d ε v p = d ε v ( K K + d p b d ε v p ) MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamizaiabew 7aLnaaDaaaleaacaWG2baabaGaamiCaaaakiabg2da9iabgkHiTiaa dsgacqaH1oqzdaWgaaWcbaGaamODaaqabaGcdaqadaqaamaalaaaba Gaam4saaqaaiaadUeacqGHRaWkdaWcaaqaaiaadsgacaWGWbWaaSba aSqaaiaadkgaaeqaaaGcbaGaamizaiabew7aLnaaDaaaleaacaWG2b aabaGaamiCaaaaaaaaaaGccaGLOaGaayzkaaaaaa@4C3E@
d e i j p = 0 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamizaiaadw gadaqhaaWcbaGaamyAaiaadQgaaeaacaWGWbaaaOGaeyypa0JaaGim aaaa@3C92@

Elastic Properties

Yielding the cap actually models the compaction process. The elastic properties should thus increase when the porosity decreases, that is, ε v p MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqyTdu2aa0 baaSqaaiaadAhaaeaacaWGWbaaaaaa@39BA@ increases.

The variation of K MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4saaaa@36C6@ and μ with ε v p MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqyTdu2aa0 baaSqaaiaadAhaaeaacaWGWbaaaaaa@39BA@ are determined by two functions given in input.


図 5.
注: Typically, when variable elastic properties are used, the hardening parameter ε v p = d ε v p MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqyTdu2aa0 baaSqaaiaadAhaaeaacaWGWbaaaOGaeyypa0Zaa8qaaeaacaWGKbGa eqyTdu2aa0baaSqaaiaadAhaaeaacaWGWbaaaaqabeqaniabgUIiYd aaaa@4167@ and the volumetric deformation after full unloading are not consistent.

Porosity Model

The porosity model is inspired by 2 and assumes the soils are made of elastic grains with voids and is for low energies when the soil is not fully compacted. For a fully compacted soil at high energy, an equation of state should be used. In this material law, the variation of the volume of voids has an elastic part due to the elastic deformation of the skeleton and a plastic part which corresponds to the rearrangement of grains which induces compaction upon pressure loadings and dilatancy when undergoing shear loadings.
注: The presence of air is not part of this model. The porosity is defined so that it represents the volume fraction of voids, with respect to the total reference volume.
(23) n =   V v o i d V t o t a l MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbb a9q8WqFfeaY=biLkVcLq=JHqpepeea0=as0Fb9pgeaYRXxe9vr0=vr 0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaaabaaaaaaaaape GaamOBaiabg2da9iaacckadaWcaaWdaeaapeGaamOva8aadaWgaaWc baWdbiaadAhacaWGVbGaamyAaiaadsgaa8aabeaaaOqaa8qacaWGwb WdamaaBaaaleaapeGaamiDaiaad+gacaWG0bGaamyyaiaadYgaa8aa beaaaaaaaa@445F@
In the elastic case, the void volume does not change. However, in the plastic case, the porosity change is defined by: (24) n = 1 ( 1 n 0 ) e ε v p ε v 0 p MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbbG8FasPYRqj0=yi0dXdbba9pGe9xq=JbbG8A8frFve9 Fve9Ff0dmeaabaqaciGacaGaaeqabaWaaeaaeaaakeaaqaaaaaaaaa Wdbiaad6gacqGH9aqpcaaIXaGaeyOeI0YaaeWaa8aabaWdbiaaigda cqGHsislcaWGUbWdamaaBaaaleaapeGaaGimaaWdaeqaaaGcpeGaay jkaiaawMcaaiaadwgapaWaaWbaaSqabeaapeGaeqyTdu2damaaDaaa meaapeGaamODaaWdaeaapeGaamiCaaaaliabgkHiTiabew7aL9aada qhaaadbaWdbiaadAhacaaIWaaapaqaa8qacaWGWbaaaaaaaaa@4A7F@
The initial state of the pores is defined by the initial porosity, initial saturation, and initial pore pressure. The saturation is defined as the ratio of the volume of the water to the volume in the void:(25) S =   V w a t e r V v o i d MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbb a9q8WqFfeaY=biLkVcLq=JHqpepeea0=as0Fb9pgeaYRXxe9vr0=vr 0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaaabaaaaaaaaape Gaam4uaiabg2da9iaacckadaWcaaWdaeaapeGaamOva8aadaWgaaWc baWdbiaadEhacaWGHbGaamiDaiaadwgacaWGYbaapaqabaaakeaape GaamOva8aadaWgaaWcbaWdbiaadAhacaWGVbGaamyAaiaadsgaa8aa beaaaaaaaa@4443@

The above voids can be partly or totally filled with water. In soil mechanics, when the soil is not saturated S < 1 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4uaiabgY da8iaaigdaaaa@388E@ the only effect of water is its weight and mass so the water pressure u = 0 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyDaiabg2 da9iaaicdaaaa@38B1@ ; the mechanical properties are then the same as the drained soil. When the soil is saturated S 1 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4uaiabgw MiZkaaigdaaaa@3950@ , the water pressure u MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyDaaaa@36F1@ is taken into account using Terzaghi’s assumption. 3 The total pressure is p = p ' + u MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCaiabg2 da9iaadchadaahaaWcbeqaaiaacEcaaaGccqGHRaWkcaWG1baaaa@3BA5@ , where p MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCaaaa@36EC@ is the effective pressure in the structure that has the voids. Also, assume the initial water pressure does not exceed the initial pressure in the skeleton.

The average density of the void can be calculated as the mass of the water divided by the volume of the void:(26) ρ v o i d = m w a t e r V v o i d MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqyWdi3aaS baaSqaaiaadAhacaWGVbGaamyAaiaadsgaaeqaaOGaeyypa0ZaaSaa aeaacaWGTbWaaSbaaSqaaiaadEhacaWGHbGaamiDaiaadwgacaWGYb aabeaaaOqaaiaadAfadaWgaaWcbaGaamODaiaad+gacaWGPbGaamiz aaqabaaaaaaa@477A@
Next, define: (27) μ w = ρ v o i d ρ w 0 1 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbb a9q8WqFfeaY=biLkVcLq=JHqpepeea0=as0Fb9pgeaYRXxe9vr0=vr 0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaaabaaaaaaaaape GaeqiVd02damaaBaaaleaapeGaam4DaaWdaeqaaOGaeyypa0ZaaSaa aeaacqaHbpGCdaWgaaWcbaGaamODaiaad+gacaWGPbGaamizaaqaba aakeaacqaHbpGCdaWgaaWcbaGaam4DaiaaicdaaeqaaaaakiabgkHi Tiaaigdaaaa@4548@

Where, ρ w 0 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbb a9q8WqFfeaY=biLkVcLq=JHqpepeea0=as0Fb9pgeaYRXxe9vr0=vr 0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaaiabeg8aYnaaBa aaleaacaWG3bGaaGimaaqabaaaaa@398E@ is the initial density of the water.

For stability reasons, a viscousity term is added.

If μ w >   t o l  then  u v i s =   α v K w   ρ   ( V o l ) 1 3   ε v MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaaeaaaaaaaaa8 qacqaH8oqBpaWaaSbaaSqaa8qacaWG3baapaqabaGcpeGaeyOpa4Ja eyOeI0IaaiiOaiaadshacaWGVbGaamiBaiaabccacaqG0bGaaeiAai aabwgacaqGUbGaaeiiaiaadwhapaWaaSbaaSqaa8qacaWG2bGaamyA aiaadohaa8aabeaak8qacqGH9aqpcaGGGcGaeyOeI0IaeqySde2dam aaBaaaleaapeGaamODaaWdaeqaaOWdbmaakaaapaqaa8qacaWGlbWd amaaBaaaleaapeGaam4DaaWdaeqaaOWdbiaacckacqaHbpGCaSqaba GccaGGGcWaaeWaa8aabaWdbiaadAfacaWGVbGaamiBaaGaayjkaiaa wMcaa8aadaahaaWcbeqaa8qadaWcaaWdaeaapeGaaGymaaWdaeaape GaaG4maaaaaaGccaGGGcGaeqyTdu2damaaBaaaleaapeGaamODaaWd aeqaaaaa@5FD8@ and is added to u * MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyDamaaCa aaleqabaGaaiOkaaaaaaa@37CB@ .

For a smoother transition, define:(28) If  μ w < t o l : u * =   0 If  | μ w | < t o l : u * =   K w 4 t o l   ( μ w + t o l ) 2 If  μ w > t o l : u * =   K w   μ w MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGceaqabeaaqaaaaa aaaaWdbiaabMeacaqGMbGaaeiiaiabeY7aT9aadaWgaaWcbaWdbiaa dEhaa8aabeaak8qacqGH8aapcqGHsislcaWG0bGaam4BaiaadYgaca GG6aGaamyDa8aadaahaaWcbeqaa8qacaGGQaaaaOGaeyypa0JaaiiO aiaaicdaaeaacaqGjbGaaeOzaiaabccadaabdaWdaeaapeGaeqiVd0 2damaaBaaaleaapeGaam4DaaWdaeqaaaGcpeGaay5bSlaawIa7aiab gYda8iaadshacaWGVbGaamiBaiaacQdacaWG1bWdamaaCaaaleqaba WdbiaacQcaaaGccqGH9aqpcaGGGcWaaSaaa8aabaWdbiaadUeapaWa aSbaaSqaa8qacaWG3baapaqabaaakeaapeGaaGinaiaadshacaWGVb GaamiBaaaacaGGGcWaaeWaa8aabaWdbiabeY7aT9aadaWgaaWcbaWd biaadEhaa8aabeaak8qacqGHRaWkcaWG0bGaam4BaiaadYgaaiaawI cacaGLPaaapaWaaWbaaSqabeaapeGaaGOmaaaaaOWdaeaapeGaaeys aiaabAgacaqGGaGaeqiVd02damaaBaaaleaapeGaam4DaaWdaeqaaO GaeyOpa4ZdbiaadshacaWGVbGaamiBaiaacQdacaWG1bWdamaaCaaa leqabaWdbiaacQcaaaGcpaGaeyypa0ZdbiaacckacaWGlbWdamaaBa aaleaapeGaam4DaaWdaeqaaOWdbiaacckacqaH8oqBpaWaaSbaaSqa a8qacaWG3baapaqabaaaaaa@7D59@
Where, K w MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaaeaaaaaaaaa8 qacaWGlbWdamaaBaaaleaapeGaam4DaaWdaeqaaaaa@383C@ is the water bulk modulus.


図 6. Pressure, due to Porosity
The cap is then modified by adding a purely von Mises region for p 0 p ' p 0 + u * MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCamaaBa aaleaacaaIWaaabeaakiabgsMiJkaadchadaahaaWcbeqaaiaacEca aaGccqGHKjYOcaWGWbWaaSbaaSqaaiaaicdaaeqaaOGaey4kaSIaam yDamaaCaaaleqabaGaaiOkaaaaaaa@41B9@ .


図 7. Modification to the Cap
1 Drücker D. and Prager W., 「Soil mechanics and plastic analysis of limit design」, Quart. Appl. Math., Vol. 10, 157-165, 1952.
2 R. Kohler and G. Hofstetter, A cap model for partially saturated soils, Wiley & Sons, 2007
3 Karl Terzaghi, Theoretical Soil Mechanics, Wiley & Sons, 1943