The deformation behaviour and pressure-dependent failure mode of porous soft rocks are effectively captured through discrete element method (DEM) modelling. To identify a compromise between the effects of compaction hardening and structural deterioration caused by frictional unbonded contacts and damaged or broken bonds, a macro-element-based theory combined with exponential damage laws governing plastic deformations is employed to develop a novel bond damage contact model at the microscale. Furthermore, to accurately represent irregularly shaped grains and account for the physical presence of bond fragments in porous structures using spherical particles, the model is implemented within a far-field interaction framework, enabling load transmission between non-contacting particles. The contact model is calibrated to replicate the behaviour of two typical soft rocks, Maastricht calcarenite and St. Nicholas-Wade chalk, using laboratory data from the literature. The scalable calibrated model is then used to simulate large-scale boundary value problems such as open-ended pile installation and hereto the results are compared with field tests from the literature.
Ciantia et al. (Sun,) studied this question.