考虑粒径对砂土宏细观剪切性质的试验研究  

Experimental Study on Micro-macro Shear Properties of Sand Considering Particle Size

作　　者：王博 吕果 李江[1] Wang Bo;Lv Guo;Li Jiang(Construction Comprehensive Survey,Research and Design Institute Co.,Ltd.,Beijing 100007,China)

机构地区：[1]建设综合勘察研究设计院有限公司,北京100007

出　　处：《岩土工程技术》2023年第5期618-622,共5页Geotechnical Engineering Technique

摘　　要：为探究砂土粒径对其抗剪强度的影响,利用应变控制式直剪仪和离散元软件,分别进行了3种不同平均粒径砂的剪切试验,从宏观、细观两个角度对砂展开了剪切特性分析。研究表明:抗剪强度随法向应力和平均粒径的增加而增大,内摩擦角随平均粒径的增加而增大。建立了砂土抗剪强度多元线性预测模型,且模型预测准确。平均粒径的增加致使剪切带厚度增大。剪切带厚度与法向应力关系可用一元二次函数表达。因此,在实际工程施工中,合理采用粒径较大的砂土有利于提高抗剪能力。In order to explore the influence of sand particle size on its shear resistance,strain controlled direct shear apparatus and discrete element software were used to conduct shear tests on three kinds of sand with different average particle sizes,and the shear characteristics of sand were analyzed from both macro and micro perspectives.The results show that the shear strength increases with the increase of normal stress and average particle size,and the internal friction angle increases with the increase of average particle size.A multivariate linear prediction model of sand shear strength is established,and the model prediction is accurate.The thickness of shear band increases with the increase of average particle size.The relationship between shear band thickness and normal stress can be expressed by a quadratic function.Therefore,in the actual project construction,reasonable use of sand with larger particle size is conducive to improving the shear capacity.

关 键 词：砂土 平均粒径 抗剪强度 数值模拟 剪切带厚度 

分 类 号：TU411[建筑科学—岩土工程]