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An increase in the operation speed of high-speed trains often leads to an increase in the loading frequency on subgrade soil. Hence, the long-term dynamic behavior of the subgrade and the service performance of high-speed tracks are affected. To determine the stress-strain characteristics of granular soil under high-frequency loading, a triaxial test setup was modified to investigate the effects of loading acceleration and duration, water content, vibration frequency, cell pressure, and initial soil density. The experimental results indicate that there are reductions in axial stress and volumetric strain during high-frequency loading. The reduction in axial stress is as high as 40%, and that of volumetric strain, which is permanent, could approach 0.1%. The stress reduction, strain compression, and excess pore pressure are found to vary linearly with vibration acceleration when a/g > 0.02, where a is vertical vibration acceleration and g is gravitational acceleration. The reduction in strength and strains are found to depend on the loading acceleration and effective cell pressure, but independent of the loading duration, water content, frequency, and initial density. A threshold acceleration a = 0.02g is observed, below which the changes in the shear strength and volumetric strain induced by vibration are negligible. At high vibration acceleration, the strain amplitude could increase, eventually leading to a collapse of the specimen. Key words: granular soil, critical state, fluidization, deviatoric stress, volumetric strain. L'augmentation de la vitesse d'exploitation des trains a grande vitesse entraine souvent une augmentation de la frequence de chargement du sol de la plate-forme. Le comportement dynamique a long terme de la plate-forme et les performances de service des voies a grande vitesse sont donc affectes. Afin de determiner les caracteristiques de contraintedeformation du sol granulaire sous un chargement a haute frequence, un montage d'essai triaxial a ete modifie pour etudier les effets de l'acceleration et de la duree du chargement, de la teneur en eau, de la frequence de vibration, de la pression des cellules et de la densite initiale du sol. Les resultats experimentaux indiquent qu'il y a des reductions de la contrainte axiale et de la deformation volumetrique pendant le chargement a haute frequence. La reduction de la contrainte axiale peut atteindre 40% et celle de la deformation volumetrique, qui est permanente, peut approcher 0,1%. La reduction des contraintes, la compression des deformations et l'exces de pression interstitielle varient lineairement avec l'acceleration des vibrations lorsque a/g > 0,02 ou a est l'acceleration de vibration verticale et g est l'acceleration gravitationnelle. La reduction de la resistance et des deformations depend de l'acceleration de la charge et de la pression effective des cellules, mais est independante de la duree de la charge, de la teneur en eau, de la frequence et de la densite initiale. Un seuil d'acceleration a = 0.02g est observe, en dessous duquel les changements de la resistance au cisaillement et de la deformation volumetrique induits par la vibration sont negligeables. En cas d'acceleration elevee, l'amplitude de la deformation peut augmenter et conduire a l'effondrement du specimen. [Traduit par la Redaction] Mots-cles: sol granulaire, etat critique, fluidization, contrainte deviatorique, deformation volumetrique., 1. Introduction Vibrations induced by high-speed trains frequently lead to long-term settlement of the track owing to the permanent compression of the subgrade. When the speed of a high-speed train [...]

Background: Multiple morphological abnormalities of sperm flagella is an idiopathic asthenoteratozoospermia characterized by absent, short, coiled, angulation, and irregular‐caliber flagella. Genetic variants of DNAH1 gene have been identified as a causative factor of multiple morphological abnormalities of sperm flagella and intracytoplasmic sperm injection is an available strategy for infertile males with dynein axonemal heavy chain 1 defects to conceive. Objectives: To identify novel variants and candidate mutant hotspots of DNAH1 gene related to multiple morphological abnormalities of sperm flagella and male infertility in humans. Materials and methods: The DNAH1 variants were identified by whole exome sequencing and confirmed with Sanger sequencing. Papanicolaou staining, scanning and transmission electron microscopy, and immunostaining were performed to investigate the morphological and ultrastructural characteristics of spermatozoa. Intracytoplasmic sperm injection was applied for the assisted reproductive therapy of males harboring biallelic DNAH1 variants. Results: We identified 18 different DNAH1 variants in 11 unrelated families, including nine missense variants (p.A2564T, p.T3657R, p.G1862R, p.L2296P, p.T4041I, p.L611P, p.A913D, p.R1932Q, p.R2356W) and nine loss‐of‐function variants (c.2301‐1G>T, p.Q1518*, p.R1702*, p.D2845Mfs*2, p.P3909Rfs*33, p.Q4040Dfs*33, p.Q4058*, p.E4060Pfs*61, p.V4071Cfs*54). A total of 66.7% (12/18) of the identified variants were novel. Morphological analysis based on Papanicolaou staining and scanning electron microscopy demonstrated the typical multiple morphological abnormalities of sperm flagella characteristics of dynein axonemal heavy chain 1‐deficient spermatozoa. Immunostaining further revealed the absence of inner dynein arms but not outer dynein arms, which induced a general ultrastructural disorganization, such as the loss of central pair and mis‐localization of the microtubule doublets and outer dense fibers. To date, seven affected couples have accepted the intracytoplasmic sperm injection treatment, and three of them have given birth to five healthy babies. Discussion and conclusion: These findings further expand the variant spectrum of DNAH1 gene related to multiple morphological abnormalities of sperm flagella and male infertility in humans, thus providing new information for the molecular diagnosis of asthenoteratozoospermia. The favorable fertility outcomes of intracytoplasmic sperm injection will facilitate the genetic counseling and clinical treatment of infertile males with multiple morphological abnormalities of sperm flagella in the future. [ABSTRACT FROM AUTHOR]