基于宏细观耦合的塑性混凝土力学特性模拟研究  

Mesoscopic Simulation of Plastic Concrete Based on DEM-flexible Boundary

作　　者：张宝增[1] 李宝国[1] 江志安[1] 崔溦[2,3] 唐贝 ZHANG Bao-zeng;LI Bao-guo;JIANG Zhi-an;CUI Wei;TANG Bei(Sinohydro Foundation Engineering Co.,Ltd,Tianjin 301700,China;State Key Laboratory of Hydraulic Engineering Simulation and Safety,Tianjin University,Tianjin 300350,China;Key Laboratory of Earthquake Engineering Simulation and Seismic Resilience of China Earthquake Administration,Tianjin University,Tianjin 300350,China)

机构地区：[1]中国水电基础局有限公司天津市地基与基础工程企业重点实验室,天津301700 [2]天津大学水利工程仿真与安全国家重点实验室,天津300350 [3]天津大学中国地震局地震工程综合模拟与城乡抗震韧性重点实验室,天津300350

出　　处：《中国农村水利水电》2024年第2期240-247,共8页China Rural Water and Hydropower

基　　金：国家自然科学基金资助项目(52079092)。

摘　　要：为揭示塑性混凝土细观破坏机理,基于PFC-FLAC3D耦合建立了柔性膜边界三轴试验模型,深入分析了塑性混凝土在围压效应和尺寸效应下的细观变形破坏特征,采用多元非线性公式定量描述了塑性混凝土宏观单轴力学强度-围压-三轴力学强度的经验函数关系,并结合室内试验结果验证了经验公式的准确性。研究结果表明:围压越大,对内部颗粒运动约束越强,低围压下的剪切带形态更明显。高围压有利于提高结构整体性,弱化抗压强度的尺寸效应。随着尺寸增加,试样中部侧向鼓胀变形减小,斜截面贯通连接的颗粒减少,导致X形剪切面特征逐渐减弱。最后,采用多元非线性拟合方法定量描述了单轴力学强度-围压-三轴力学强度联合关系,为后续研究提供理论基础。To reveal the mesoscopic failure mechanism of plastic concrete,this paper establishes a triaxial test model with flexible membrane boundary to investigate the meso-deformation and failure mechanism of plastic concrete based on PFC-FLAC3D simulation.The empirical function is derived to describe the relationship of the macroscopic uniaxial mechanical strength and triaxial mechanical strength in plastic concrete under different confining pressure by multivariate nonlinear method.The results show that the higher confining pressure restricts the internal particle motion and the shear band shape is more obvious under lower confining pressure.High confining pressure helps to improve the structural integrity and weaken the size effect of compressive strength.As the size of sample increases,the lateral bulging deformation of sample decreases and the particles connect within the oblique section decrease,resulting in the reduction of the X-shaped shear surface.Finally,the multivariate nonlinear fitting method is used to describe the relationship of uniaxial mechanical strength and triaxial mechanical strength under different confining pressure in terms of quantitative,which provides a theoretical basis for subsequent research.

关 键 词：塑性混凝土 宏细观耦合 柔性边界 力学特性 

分 类 号：TU452[建筑科学—岩土工程] TV223.1[建筑科学—土工工程]