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This study conducts a series of large-scale pullout tests to explore the pullout behavior of the biaxial geogrid-calcareous sand interface. It investigates the effects of normal stress, relative density, and embedded length on the interface pullout behavior of geogrid reinforcement in calcareous sand. In addition, this research examines changes in interface shear strength and the interface friction coefficient. The interface interaction mechanism of geogrid reinforcement in calcareous sand and the evolution of pullout force-clamp displacement curves are determined. The results indicated that the pullout force-clamp displacement curve primarily exhibits softening and hardening behaviors. The passive resistance of the geogrid mesh significantly influences the softening behavior, while shear friction predominantly affects the hardening behavior. The interface friction coefficient ranged from 0.28 to 0.88 for embedded lengths of 300 − 460 mm. The effects of relative density and embedded length on interface cohesion are more pronounced than those on the interface friction angle. When the embedded length increased from 300 to 460 mm, the rise in interface cohesion ranged from 42.0% to 47.7%, whereas the increase in internal friction angle ranged from 9.5% to 14.5%. [ABSTRACT FROM AUTHOR]

Coral reef limestone (CRL) is a marine sedimentary rock dominated by biogenesis, and its composition as well as internal structure characteristics are different from traditional terrigenous rocks. This article used CT scanning and petrographic thin section observations to visually and quantitatively analyze crack morphological characteristics after triaxial shear failure at a microscopic scale. The analysis revealed the mechanism of crack initiation and propagation from the perspectives of geological genesis and fracture mechanics. Results show that the crack propagation mechanism in the bio-cemented framework includes propagation along crystal boundaries and across crystals. Cracks can be classified as intergranular cracks, transgranular cracks, and bifurcation cracks based on crack morphology. The destruction mode of the specimen is controlled by the pore structure and cemented framework. Based on the pore distribution, the destruction mode can be divided into local tension failure and monoclinic shear failure. Understanding CRL crack propagation mechanisms has important scientific significance and practical engineering value for enriching rock damage theory and long-term stability analysis of island reef engineering foundations. [ABSTRACT FROM AUTHOR]

This technical note used the finite element method to investigate the consolidation behaviour of circular footings embedded in a finite stratum based on Biot's consolidation theory. The influence of three factors on the degree of consolidation settlement was examined: (1) the ratio of the buried depth to the thickness of the stratum, (2) the ratio of the footing radius to the thickness of the stratum, and (3) the Poisson's ratio of the soil skeleton. Based on the results of analysis, new normalized time factors are suggested. It is shown that the degree of consolidation exhibits very good normalized behaviour using the time factors. The authors also present solution charts for determining the degree of consolidation settlement of circular footings embedded in a finite stratum. These charts can provide engineers with a quick answer to the design issues. The maximum error caused by using the solution charts is within 3%. Key words: consolidation, embedded circular footing, solution charts, finite element method, coupled analysis. Cette note technique presente une utilisation de la methode des elements finis pour investiguer le comportement en consolidation de semelles circulaires incorporees dans une strate finie, basee sur la theorie de la consolidation de Biot. L'influence de trois facteurs sur le degre de tassement par consolidation sont examines : (1) le ratio de la profondeur sur l'epaisseur de la strate, (2) le ratio du rayon de la semelle sur l'epaisseur de la strate, (3) le ratio de Poisson du squelette du sol. Des nouveaux facteurs de temps normalises sont proposes base sur les resultats de l'analyse. La note technique demontre que le degre de consolidation presente un comportement normalise tres bon en utilisant les facteurs de temps. Les auteurs presentent des graphiques de solution pour determiner le degre de tassement par consolidation de semelles circulaires incorporees dans une strate finie. Les graphiques peuvent fournir une reponse rapide aux ingenieurs lors de problemes de conception. Mots-cles : consolidation, semelles circulaires incorporees, graphiques de solution, methodes des elements finis, analyse couplee. [Traduit par la Redaction], Introduction In the design of construction on compressible ground, it is customary to embed the foundation in the ground. An embedded foundation has the following effects in comparison with a [...]