考虑结构构成的冰水堆积体变形破坏分析

Deformation and failure analysis of the glacial deposit considering structure and composition

冰水堆积体为一种受结构构成影响显著的典型土石混合介质,其在荷载作用下的承载力丧失是一个渐进破坏过程。采用随机块体生成技术重构冰水堆积体细观结构特征,并以单向受力下的极限剪应变作为参量,进行不同结构构成下的冰水堆积体单轴压缩数值模拟,研究冰水堆积体结构构成对其变形破坏以及破坏规律的影响。结果表明:冰水堆积体剪切变形破坏具有明显的绕石现象;随着内部岩块含量增加,冰水堆积体剪切应变区、极限剪应变均随之增大,且极限剪应变与岩块含量近似成指数增长关系;不同岩块倾角下的变形破坏数值模拟结果则表明,冰水堆积体极限剪应变区分布与岩块倾角具有一致性,极限剪应变与岩块倾角近似成Λ关系。冰水堆积体随机结构重构方法及破坏规律可为工程安全评价及综合治理提供理论与技术参考。

The glacial deposit is a typical soil–rock mixture.Its mechanical property is strongly affected by its structural composition.The bearing capacity of glacial deposit losses gradually when it suffers from gravity or other kinds of loadings.In this study,the algorithm of random rock block generation was used to reconstruct the meso structure of the glacial deposit.The ultimate shear strain under uniaxial pressure was used as a parameter for failure analysis.The deformation and failure of the glacial deposit with different structures and composition under uniaxial pressure was then simulated to understand the deformation process and failure law.Numerical simulations indicate that:(1)The glacial deposit under uniaxial pressure exhibits a significant phenomenon of getting round stone blocks during the shear deformation and failure process;(2)Both the shear strain zone and the ultimate shear strain increase with the increase of the content of rock block,besides the relationship between the ultimate shear strain and the content of rock block experiences an exponential growth.Results from the shear deformation and failure analysis of the glacial deposit with different inclinations of rock blocks show that:(1)The distribution of the shear strain zone under axial pressure always has good uniformity with the inclination of stone blocks;(2)The relationship between the ultimate shear strain and the inclinations of rock blocks takes on a shape ofΛ.The random structure reconstruction method and the failure law of the glacial deposit can provide theoretical and technical reference for engineering safety and comprehensive reinforcement.