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This paper intends to identify the safety and stability issues within quay structures, including scouring and hollowing, in the infrastructure for off-shore rubble bed. The three main research approaches are to combine 3D laser scanning technology, particle discrete element method and on-site experiments. The rubble bed model is established using the rigid block (Rblock) element in discrete element particle flow. Combined with the gradation generation method and the calibration of on-site tests, the influencing factors and evolution characteristics of vibratory compaction technique of rubble bed are then numerically investigated. First, the shape of the on-site stones is characterized using 3D mesoscopic extraction by 3D laser scanning technology.Statistics are used to examine the shape charactrization parameters of stone particles, and 3D mesoscopic characterization description and reconstruction techniques are developed for stone particles. Second, the 3D model of rubble bed is then built using the Rblock element in discrete particle flow, and the necessary model parameters are calibrated through a on-site vibratory compaction test. Additionally, the PFC3D program is used to study two types of influencing factors, namely the particle characteristics and vibration conditions during the vibratory compaction process of rubble bed. The results show how the riprap thickness, particle size, grading effect, vibration time, vibration frequency, and effective excitation amplitude affect the vibratory compactory properties of rubble bed. The functional link between various influencing factors with density degree and deformation modulus is proposed after combining experimental tests to examine the relevance between compaction parameters with density degree after vibration and deformation modulus. The suggested discrete element method can serve as a guide for vibratory rubble bed compaction. [ABSTRACT FROM AUTHOR]

The advancement of technology, especially the development and application of artificial intelligence, has deeply affected the education sector and brought opportunities for pedagogical adaptation. Intelligent tutoring systems, a major application of artificial intelligence in education, have drawn extensive concerns. However, in reality, the penetration rate of intelligent tutoring systems and the enthusiasm of faculty to use are still relatively low. This research examined the determinants of the willingness of faculty to use intelligent tutoring systems. Innovation diffusion theory was the theoretical basis of this research and it was adapted by incorporating perceived trust and experience. To gather data, a cross-sectional questionnaire survey was performed and structural equation modeling was employed to analyze the data. The findings indicated that relative advantage, compatibility, perceived trust and experience are the contributing determinants of the willingness of faculty to use intelligent tutoring systems, while complexity has no significant effect. Meanwhile, complexity is significantly negatively affected by experience and compatibility. Relative advantage is significantly positively affected by perceived trust but not by complexity. Based on the research findings, relevant recommendations for encouraging faculty to use intelligent tutoring systems were proposed.

This paper describes an experimental investigation of a newly developed driven and grouted soil nail (x-Nail), which combines the capabilities of a purely frictional driven nail and a compaction-grouted nail. The innovative design allows the x-Nail to be driven into the ground with a latex balloon attached that is subsequently used for compaction grouting. A grout bulb is thus formed at the driven end of the nail to improve its pull- out resistance. For compaction grouting, a special type of additive-mixed cement grout was used in this investigation because of its zero bleeding and high bond strength. A series of pullout model tests was conducted to examine the performance of the x-Nail compared to a purely frictional soil nail. It was found that more than 90% of the pullout force of the x-Nail was resisted by the expanded grout bulb and the end bearing resistance of the grout bulb increased with the increment of the injected grout volumes. The experimental results revealed that the pullout force of the x-Nail increased approximately 1800%, 1550%, 1200%, and 900% compared to the purely frictional soil nail for the injected grout volumes of about 350, 270, 220, and 170 mL, respectively. Key words: soil nail, compaction grouting, pullout force, pullout test, zero bleeding grout. Cet article decrit une etude experimentale d'un nouveau clou de sol enfonce et injecte de coulis (x-Nail), qui combine les capacites d'un clou enfonce purement par friction et d'un clou a coulis de compactage. La conception innovante permet d'enfoncer le x-Nail dans le sol a l'aide d'un ballon en latex qui est ensuite utilise pour le coulis de compactage. Un bulbe de coulis est ainsi forme a l'extremite enfoncee du clou pour ameliorer sa resistance a l'arrachement. Pour les coulis de compactage, un type special de coulis de ciment melange a des additifs a ete utilise dans cette etude en raison de son absence de ressuage et de sa grande force d'adherence. Une serie de tests d'arrachement sur modele a ete menee pour examiner les performances du x-Nail par rapport a un clou de sol purement frictionnel. Il a ete constate que plus de 90 % de la force d'arrachement du x-Nail etait resistee par le bulbe de coulis expanse et que la resistance du bulbe de coulis a l'extremite augmentait avec l'augmentation des volumes de coulis injectes. Les resultats experimentaux ont revele que la force d'arrachement du x-Nail a augmente d'environ 1800,1550,1200 et 900 % par rapport au clou de sol purement frictionnel pour les volumes de coulis injectes d'environ 350, 270, 220 et 170 mL, respectivement. [Traduit par la Redaction] Mots-cles: clou de sol, coulis de compactage, force d'arrachement, test d'arrachement, coulis sans ressuage., Introduction Soil nailing is an effective and economical reinforcement technique in which the reinforcing slender elements (typically steel bars), called soil nails, are inserted into a soil mass by different [...]