报告摘要
Deformation localization, frequently accompanied by strength loss, is an instability phenomenon observed in geomaterials. This phenomenon threatens the short- and long-term safety of geoengineering systems, e.g., the shear failure of shallow foundations and the compaction instability of subsurface energy storage media. However, the application of classical continuum models in simulations of localized deformation often encounters problems related to mesh dependency. This talk discusses recent progress in regularized numerical simulations of strain localization in plastic geomaterials. To this end, a nonlocal implicit gradient regularization strategy is considered. First, the conditions at which regularization is achieved or lost under the mixed effects of material softening and plastic non-normality are detected mathematically by referencing the concept of controllability for plastic solids. Then, numerical simulations are carried out, through the implementation of a robust coupled finite element procedure, to show that the thickness of the deformation band is linked to both the controllability modulus and gradient regularization constants, which suggests that the thickness of the process zone may change in response to the prevailing plastic flow characteristics and evolve during active plastic deformation. Finally, the proposed framework is further developed to reproduce the size-dependent responses of geo-structural systems, a phenomenon widely observed in geotechnical centrifuge tests and is deemed as heavily related to shear banding inside soils that scale within a specific range. As a consequence, a novel centrifuge scaling law is introduced through a series of simulations that encompass various combinations of gravity acceleration and shallow foundation size. These studies highlight the challenges in modeling the mechanical response of granular materials prone to plastic localized deformation and provide guidance for further development and application of nonlocal implicit gradient enhancement techniques, which effectively capture the initiation and propagation of deformation bands in geomaterials and their associated consequences.
主讲人简介
薛大为博士现为同济大学特聘研究员，研究方向包括岩土材料高阶本构模型、材料稳定性理论及跨尺度数值方法，近五年已在《Computer Methods in Applied Mechanics and Engineering》、《Acta Geotechnica》、《Computers and Geotechnics》、《International Journal for Numerical and Analytical Methods in Geomechanics》、《岩土工程学报》、《中国科学-技术科学》等国际国内知名学术期刊发表SCI论文13篇、EI论文5篇，获国际专利1项，申请发明专利2项，实用新型专利3项及软件著作权4项，受邀作国际会议报告5次。曾获博士研究生国家奖学金、中冶集团科技进步一等奖、同济大学优秀博士学位论文，并入选上海市领军（海外）人才计划。薛大为博士目前担任《Biogeotechnics》青年编委、《International Journal for Numerical and Analytical Methods in Geomechanics》、《Computational Particle Mechanics》、《Natural Hazards》等SCI期刊审稿人、中国岩石力学与工程学会会员、中国土木工程学会会员。
协办单位：浙江省力学学会岩土力学与工程专业委员会、浙江省岩土力学与工程学会本构理论与数值分析专业委员会、浙江大学岩土工程计算中心、浙江省土木建筑学会土力学及岩土工程学术委员会