锚-土界面拉拔试验与剪应力分布规律研究  

Pull-out Tests and Shear Stresses Distribution at the Anchor-soil Interface

作　　者：董捷 孙京华 陶春晨 DONG Jie;SUN Jinghua;TAO Chunchen(College of Civil Engineering,Heibei University of Architecture,Zhangjiakou,Hebei 075000,China;Hebei Innovation Center of Transportation Infrastructure in Cold Region,Zhangjiakou,Hebei 075000,China)

机构地区：[1]河北建筑工程学院土木工程学院,河北张家口075000 [2]河北省寒冷地区交通基础设施工程技术创新中心,河北张家口075000

出　　处：《公路工程》2022年第5期176-182,共7页Highway Engineering

基　　金：国家自然科学基金项目(51878242);河北省自然科学基金项目(E2020404007);河北省人才工程培养资助项目(A201901067)。

摘　　要：为研究锚-土界面的作用机理,通过锚-土界面拉拔试验,分析了围压和含水率对土层锚杆极限抗拔力的影响;基于PFC3D程序对土层锚杆进行数值模拟研究,从细观角度揭示了锚-土界面剪应力分布特征与其传递规律。结果表明:当土样含水率一定时,土体所受应力状态对试样的极限抗拔力影响较大,即围压越高,与其极限抗拔力越大;在相同围压条件下,土层锚杆的极限抗拔力随含水率的增加呈现出先增大后减少的趋势,当土质含水率接近其最佳含水率8.45%时,锚杆的支护效果比较好;锚-土界面剪应力(X-Z方向)沿锚固体分布极不均匀;另外,峰值剪应力并未出现在锚固段顶部,而是位于距离锚固体顶端较近的监测球B处;锚-土界面极限抗拔力数值模拟结果与室内试验结果有较好的一致性,颗粒流模型为锚-土界面的锚固机理的细观尺度研究提供了可行性。To explore mechanism of the anchor-soil interface,the influence of moisture content and confining pressure on the ultimate drawing forces of soil anchors are analyzed through the drawing tests in the room of anchor-soil interface.Based on the three-dimensional discrete element method,the numerical simulation of soil anchor is carried out,and the distribution characteristics of the shear stress and the law of its transmission are analyzed from the microscopic perspective.The results show that under the condition of soil sample moisture content,the stresses state of soil have a great influence on the ultimate drawing forces of anchor samples.That is,the higher the confining pressure is,the greater the ultimate drawing force of the soil anchor is.Under the same confining pressure,the ultimate drawing force of soil anchor increases first and then decreases with the increase of moisture content.When the soil moisture content is close to the optimum moisture content of 8.45%,the supporting effect of the anchor is better.The distribution of shear stresses(the X-Z direction)at the anchor-soil interface are extremely uneven in the axial direction.In addition,the peak shear stress does not appear at the top of the anchorage section,but at the monitoring ball B which is close to the top of the anchor-grouting body.The results of numerical simulation of the limit drawing forces of anchor-soil interface are in good agreement with the results of laboratory tests.The particle flow model provides the feasibility for the meso-scale study of anchorage mechanism at the anchor-soil interface.

关 键 词：锚-土界面 细观 峰值剪应力 颗粒流 锚固机理 

分 类 号：TU43[建筑科学—岩土工程]