摘要
为了分析土工格栅包裹碎石桩的颗粒散体受力特性及桩体变形机理,基于室内试验结果建立离散连续耦合模型,分析应力在桩体中的传递规律、径向应力系数的相关影响因素、桩体和土工格栅中力链的发展规律以及加筋碎石桩的破坏模式。结果表明:碎石桩的径向应力系数(被动土压力系数)并非定值,桩体破坏时径向应力系数较加载初期最大下降44.8%;径向应力系数变化的根本原因是碎石桩骨架受力结构的变化;全长加筋包裹碎石桩的破坏模式为顶部鼓胀破坏,其细观表现为桩顶部位孔隙率增大,格栅力链大面积断裂,碎石颗粒产生大幅度侧向位移;在承载过程中,格栅横肋提供显著的约束应力而格栅纵肋受力极小,主要作用为固定和支撑格栅横肋。
To analyze the mechanical characteristics and deformation mechanism of geosynthetic encased stone columns,a model that combines the discrete element method(DEM)and the finite difference method(FDM)is adopted to evaluate the laboratory test results.The stress transfer law in the pile,the related influencing factors of radial stress coefficient,the development law of stress chain in the pile and geogrid,and the failure mode of geosynthetic encased stone columns are analyzed.The results show that the radial stress coefficient(passive earth pressure coefficient)of geosynthetic encased stone columns is not a fixed value,and the radial stress coefficient decreases by 44.8% compared with the initial loading stage when the pile is damaged.The fundamental reason for the change of radial stress coefficient is the change of stress structure of gravel pile skeleton.The failure mode of full-length reinforced gravel pile is top bulging failure,and its mesoscopic performance is the increase of porosity at the top of pile.Geogrid force chain breaks in a large area,and the gravel particles produce a large lateral displacement.The circumferential geogrid provides significant restraint stress,while the longitudinal geogrid is mainly used to fix and support the circumferential geogrid.
作者
黄世斌
邹辰皓
王家全
周圆兀
HUANG Shi-bin;ZOU Chen-hao;WANG Jia-quan;ZHOU Yuan-wu(College of Civil and Architectural Engineering,Guangxi University of Science and Technology,Liuzhou 545006,China;Guangxi Zhuang Autonomous Region Engineering Research Center of Geotechnical Disaster and Ecological Control,Liuzhou 545006,China)
出处
《广西大学学报（自然科学版）》
CAS
北大核心
2022年第1期13-21,共9页
Journal of Guangxi University（Natural Science Edition）
基金
国家自然科学基金项目(41962017)
广西自然科学基金项目(2017GXNSFAA198170)
广西高等学校高水平创新团队及卓越学者计划项目(桂教人才〔2020〕6号)
广西研究生教育创新计划项目(YCSW2020222)
广西大学生创新创业训练计划项目(202010594037)。
关键词
加筋碎石桩
数值模拟
耦合
承载肌理
geosynthetic encased stone columns
numerical simulation
coupling
bearing mechanism
