Time-dependency of soft soils


Natural soft clays exhibit several features: (a) significant anisotropy developed during their deposition, sedimentation, consolidation history and any subsequent straining; (b) some apparent bonding which will be progressively lost during straining; and (c) time-dependent stress-strain behaviour which has a significant influence on the shear strength and the pre-consolidation pressure. Since all these features cannot be neglected, in the modelling we considered all above features. The application of the proposed model ANICREEP requires the same experimental information as needed for the Modified Cam Clay model, which makes the model attractive for geotechnical practice.

Topic 1: Experimental observations

We proposed the coefficient of stress relaxation, uniqueness of time-dependency (rate-dependency, creep and stress relaxation), rate-dependent stress-strain-time relationship, consideration of interparticle bonding and debonding.

  • Han J, Yin Z-Y*, Dano C, Hicher PY (2021). Cyclic and creep combination effects on the long-term undrained behavior of overconsolidated clay. Acta Geotech., DOI: 10.1007/s11440-020-01078-5.
  • Zhao D#, Gao Q, Hattab M, Hicher P-Y, Yin Z-Y*(2020). Microstructural evolution of remolded clay related to creep. Transp. Geotech., 24: 100367.
  • Zhao D#, Hattab M, Yin Z-Y, Hicher P-Y (2019). Dilative Behavior of Kaolinite under Drained Creep Condition. Acta Geotech., 14(4): 1003–1019.
  • Feng WQ#, Lalit B, Yin Z-Y, Yin, J-H (2017). Long-term non-linear creep and swelling behavior of Hong Kong marine deposits in oedometer condition. Comput. Geotech., 84(4): 1-15.
  • Zhu QY#, Yin Z-Y*, Hicher PY, Shen SL (2016). Nonlinearity of one-dimensional creep characteristics of soft clays. Acta Geotech., 11(4): 887-900.
  • Wang L-Z, Yin Z-Y*(2015). Stress-dilatancy of natural soft clay under undrained creep condition. Int. J. Geomech. ASCE, 15(5): A4014002.

Topic 2: Elastic viscoplastic modelling

We proposed elastic viscoplastic models from one-dimensional to three-dimensional, considering anisotropy, destructuration (interparticle bonding and debonding).

  • Yin Z-Y, Zhu QY#, Zhang DM (2017). Comparison of two creep degradation modeling approaches for soft structured soils. Acta Geotech., 12(6): 1395–1413.
  • Yin Z-Y*, Xu Q, Yu C (2015). Elastic viscoplastic modeling for natural soft clays considering nonlinear creep. Int. J. Geomech. ASCE, 15(5): A6014001.
  • Yin Z-Y*, Yin JH, Huang HW (2015). Rate-dependent and long-term yield stress and strength of soft Wenzhou marine clay: experiments and modeling. Mar. Georesour. Geotec.,33(1): 79-91.
  • Yin Z-Y*, Chang CS, Karstunen M, Hicher PY (2010). An anisotropic elastic viscoplastic model for soft clays. Int. J. Solids Struct., 47(5): 665-677.
  • Yin Z-Y*, Karstunen M, Chang CS, Koskinen M, Lojander M (2011). Modeling time-dependent behavior of soft sensitive clay. J. Geotech. Geoenviron. Eng. ASCE, 137(11): 1103-1113.
  • Yin Z-Y*, Karstunen M, Hicher PY (2010). Evaluation of the influence of elasto-viscoplastic scaling functions on modelling time-dependent behaviour of natural clays. Soils Found., 50(2): 203-214.

Topic 3: Key parameters and determination methods

We developed machine learning based correlation models for creep index, optimization-based inverse analysis for parameters of ANICREEP model based on conventional laboratory tests (one oedometer test+ three triaxial tests).

  • Zhang P#, Yin Z-Y*, Jin YF#, Chan T (2020). A Novel Hybrid Surrogate Intelligent Model for Creep Index Prediction Based on Particle Swarm Optimization and Random Forest. Eng. Geol., 265(2): 105328.
  • Jin YF#, Yin Z-Y*, Zhou WH, Yin JH, Shao JF (2019). A single-objective EPR based model for creep index of soft clays considering L2 regularization. Eng. Geol., 248(8): 242-255.
  • Yin Z-Y*, Jin YF#, Shen SL, Huang HW (2017). An efficient optimization method for identifying parameters of soft structured clay by an enhanced genetic algorithm and elastic-viscoplastic model. Acta Geotech., 12(4): 849–867. (Best paper prize for 2017)

Topic 4: Time integration algorithms

We developed several time integration algorithms modified from previous ones and enhanced with adaptive substepping.

  • Li J, Yin Z-Y* (2021). Time integration algorithms for elasto-viscoplastic models with multiple hardening laws for geomaterials: enhancement and comparative study. Arch. Comput. Methods Eng., DOI: 10.1007/s11831-021-09527-4.
  • Li J, Yin Z-Y* (2020). A modified cutting-plane time integration scheme with adaptive substepping for elasto-viscoplastic models. Int. J. Numer. Meth. Eng., 121(17): 3955-3978.
  • Yin Z-Y, Li J*, Jin YF, Liu FY (2019). Estimation of robustness of time integration algorithms for elasto-viscoplastic modelling of soils. Int. J. Geomech. ASCE, 19(2): 04018197.

Topic 5: Engineering applications

The ANICREEP model was applied to different geotechncial structures, such as land reclamation, embankment, cut slope, tunnlling, etc..

  • Karstunen M, Yin Z-Y*(2010). Modelling time-dependent behaviour of Murro test embankment. Géotechnique, 60(10): 735-749.
  • Zhu QY#, Jin YF#, Yin Z-Y (2020). Modeling of embankment beneath marine deposited soft sensitive clays considering straightforward creep degradation, Mar. Georesour. Geotec., 38(5): 553-569.
  • Wang S#, Wu W, Wang J, Yin Z-Y, Cui D, Xiang W (2019). Residual-state creep of clastic soil in a reactivated slow-moving landslide in the Three Gorges Reservoir Region, China. Landslides, 15(12): 2413–2422.