通过建立路基离散元模型和土工格室有限差分模型,开展了一系列有限差分法-离散元法(finite difference method-discrete element method,简称FDM-DEM)耦合数值计算,探明了土工格室加筋路基在振动荷载作用下的压实行为。进一步揭示了土...通过建立路基离散元模型和土工格室有限差分模型,开展了一系列有限差分法-离散元法(finite difference method-discrete element method,简称FDM-DEM)耦合数值计算,探明了土工格室加筋路基在振动荷载作用下的压实行为。进一步揭示了土工格室对路基压实后水平残余应力的贡献,并在此基础上,提出了土工格室加筋路基的预应力效应,以体现施工期格室填料在经历加载并卸载后引起的格室撑阔对加筋效果的提升。结合微观接触组构、配位数变化、压实过程的应力路径,探讨土工格室加筋路基预应力效应的形成机制。研究结果表明,相较于未加筋路基,土工格室可以提高加筋路基的回弹模量,增加压实路基的水平残余应力。在振动荷载作用下,土工格室呈现上开口的喇叭形,土工格室口袋被撑阔,格室壁的最大应变为0.17%~0.21%。接触力分布也表明,在振动压实作用后,力链由竖直向水平方向发展,这体现在水平残余应力的增加,而土工格室则进一步提升了颗粒的横向接触力。展开更多
To investigate the degradation mechanism of static tensile mechanical behaviors of marble containing dynamic damage,multiple impact loading tests were performed on the disc marble samples,and then static Brazilian tes...To investigate the degradation mechanism of static tensile mechanical behaviors of marble containing dynamic damage,multiple impact loading tests were performed on the disc marble samples,and then static Brazilian tests were conducted for the damaged samples.Besides,coupling modeling technology of finite difference method(FDM)—discrete element method(DEM)was used to carry out the numerical investigation.The results show that after multiple impacts,more white patches appear on the surface,and some microcracks,macro-fractures as well as pulverized grains are found by optical microscopic.The static tensile strength decreases with the increase of the dynamic damage variable characterized by the ultrasonic wave velocity of sample.The interaction between grains in the damaged sample becomes intense in the subsequent static loading process,causing a relatively large strain.The volume of the fragments falling off around the loading points becomes larger as impact number increases.As the dynamic damage increases,the absorbed energy of sample during the static loading first decreases and then tends to be stable.Both the stress concentration and the breakage of the force chains are the root causes of the degradation of the static tensile strength.展开更多
文摘通过建立路基离散元模型和土工格室有限差分模型,开展了一系列有限差分法-离散元法(finite difference method-discrete element method,简称FDM-DEM)耦合数值计算,探明了土工格室加筋路基在振动荷载作用下的压实行为。进一步揭示了土工格室对路基压实后水平残余应力的贡献,并在此基础上,提出了土工格室加筋路基的预应力效应,以体现施工期格室填料在经历加载并卸载后引起的格室撑阔对加筋效果的提升。结合微观接触组构、配位数变化、压实过程的应力路径,探讨土工格室加筋路基预应力效应的形成机制。研究结果表明,相较于未加筋路基,土工格室可以提高加筋路基的回弹模量,增加压实路基的水平残余应力。在振动荷载作用下,土工格室呈现上开口的喇叭形,土工格室口袋被撑阔,格室壁的最大应变为0.17%~0.21%。接触力分布也表明,在振动压实作用后,力链由竖直向水平方向发展,这体现在水平残余应力的增加,而土工格室则进一步提升了颗粒的横向接触力。
基金financial support of the International Science and Technology Cooperation Plan of Jiangsu Province,China(No.BZ2020066)the National Natural Science Foundation of China(Nos.52179118,42077240 and 52074269)。
文摘To investigate the degradation mechanism of static tensile mechanical behaviors of marble containing dynamic damage,multiple impact loading tests were performed on the disc marble samples,and then static Brazilian tests were conducted for the damaged samples.Besides,coupling modeling technology of finite difference method(FDM)—discrete element method(DEM)was used to carry out the numerical investigation.The results show that after multiple impacts,more white patches appear on the surface,and some microcracks,macro-fractures as well as pulverized grains are found by optical microscopic.The static tensile strength decreases with the increase of the dynamic damage variable characterized by the ultrasonic wave velocity of sample.The interaction between grains in the damaged sample becomes intense in the subsequent static loading process,causing a relatively large strain.The volume of the fragments falling off around the loading points becomes larger as impact number increases.As the dynamic damage increases,the absorbed energy of sample during the static loading first decreases and then tends to be stable.Both the stress concentration and the breakage of the force chains are the root causes of the degradation of the static tensile strength.
