A novel discrete element method (DEM) model is proposed to better reproduce the behaviour of porous soft rocks. With the final goal of simulating pile penetration problems efficiency and scalability are two underlining features. The contact model is based on the macro-element theory and employs damage laws to govern the plastic deformations developing at the microscale. To attain (i) high porosity states, (ii) represent irregular shaped grains and (iii) incorporate the physical presence of bond fragments, the model is cast within a far-field interaction framework allowing for non-overlapping particles to transmit forces. After presenting a calibration procedure, the model is used to replicate the behaviour of Maastricht calcarenite. In particular, the mechanical response of this calcarenite is explored within the critical state theory framework. Finally, the efficiency, performance and scalability of the model is tested by simulating physical model experiments of cone-ended penetration tests in Maastricht calcarenite from the literature. To boost efficiency of the 3D numerical simulations, a coupled DEM-FDM (Finite Differential Method) framework is used. The good fit between the experimental and numerical results suggest that the new model can be used to unveil microscopic mechanism controlling the macroscopic response of soft-rock/structure interaction problems.

Integrated field and laboratory characterisation of geomaterial behaviour is critical to foundation analysis and design for a wide range of offshore and onshore infrastructure. Challenges include the need for high -quality sampling, addressing natural and induced micro -to -macro structures, and applying soil and stress states that represent both in -situ and in-service conditions. This paper draws on the Authors' recent research with stiff glacial till, dense marine sand and low -to -medium density chalk, and focuses particularly on these geomaterials' mechanical behaviour, from small strains to failure, their anisotropy and response to cyclic loading. It considers a range of in -situ techniques as well as highly instrumented monotonic and cyclic stress -path triaxial experiments and hollow cylinder apparatus tests. The outcomes are shown to have important implications for the analysis of large driven piles under monotonic -and -cyclic, axial -and -lateral loading, and the development of practical design methods. Also highlighted are the needs for approaches that integrate field observations, advanced sampling and laboratory testing, numerical and theoretical modelling.

Selliguea quinquefida (Polypodiaceae), a new calciphilous species from Guangxi, China, is described and illustrated. The new species is the second within the genus with simple and palmate fronds and unique in having simple laminae with cordiform bases. It grows in a peculiar habitat with its rhizome creeping deeply within hardened chalky soils on limestone under relatively dry conditions and always bears palmately 5-lobed fronds with pentagonal shape when fully developed. The differences and habitats among S. quinquefida and all other species with palmate fronds in the genus are discussed.

Uneven settlement phenomenon is very easy to occur in the sandy pulverized ground stratum, the underground pipe corridor longitudinal and transverse stiffness difference is obvious, so that it is easy to crack and deformation due to uneven settlement in this type of stratum. This paper carries out research on uneven settlement and cracking and deformation of Qihe tube corridor, analyzes the reasons leading to uneven settlement and the factors affecting the deformation and cracking of the tube corridor, and provides guidance for foundation treatment and tube corridor repair and mixing and reinforcement. It was found that the concrete structure of the corridor itself had exposed reinforcement, pockmarks and holes, and that cracks on the structure of the corridor sprouted and expanded from these defects. Defects and damages on the concrete structure of the pipeline corridor are contributing factors to the deformation and cracking of the members, and the uneven settlement of the foundation is the main initiating factor for the cracking and deformation. The analysis of the numerical simulation results of similar underground pipeline corridors is carried out, and it is found that the simulation results are consistent with the deformation characteristics of the Qihe pipeline corridor, which further supports the conclusions of this paper. The main stratigraphic factors contributing to the inhomogeneous settlement were found to be the water-rich and loose bodies in the lower part of the strata, as revealed by the physical means and the experimental verification boreholes. Localized hydraulic effects such as pumping further accelerate the uneven settlement of the foundation.