Rock and Soil Mechanics ›› 2020, Vol. 41 ›› Issue (7): 2304-2312.doi: 10.16285/j.rsm.2019.7115

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An elastoplastic model for energy soils considering filling and bonding effects

YUAN Qing-meng1, KONG Liang1, 2, ZHAO Ya-peng1   

  1. 1. School of Civil Engineering, Qingdao University of Technology, Qingdao, Shandong 266033, China 2. School of Science, Qingdao University of Technology, Qingdao, Shandong 266033, China
  • Online:2020-07-10 Published:2020-12-22
  • Contact: KONG Liang, male, born in 1969, Professor, Doctoral supervisor, mainly engaged in teaching and research on constitutive modelling of soils and marine geotechnics. E-mail:
  • About author:YUAN Qing-meng, male, born in 1988, PhD candidate, mainly engaged in research on marine geotechnics.
  • Supported by:
    the National Natural Science Foundation of China (11572165, 51778311).

Abstract: The filling and bonding effects of hydrate increase the compactness and strength for gas hydrate-bearing sediments(GHBS), which makes the GHBS exhibiting properties similar to dense sand or cemented soil. Under the frame of unified hardening model of clay and sand (CSUH model), the mechanical properties of GHBS are summarized firstly, and a compressive hardening parameter is introduced to describe the isotropic compression characteristics of GHBS under the double influences of filling and bonding of hydrate. A bonding parameter is put forward to modify the yield function, and an evolution rule of bonding effect is also proposed. The state parameters are used to adjust the dilatancy equation to reflect the dilatancy and softening depending on density. Thus, an elastoplastic model is developed, which can describe the strength, stiffness, shear dilation and strain-softening of GHBS. The model coded and tested, and the simulation results are compared with the experimental ones of GHBS. The results show that the proposed model can well describe the stress-strain relationship, shear contraction with hardening and shear dilation with softening for GHBS.

Key words: gas hydrate-bearing sediments, compressive hardening, bonding strength, dilatancy, CSUH model