掺砾形状及掺砾量对饱和掺砾砂土动力特性的影响研究  

Research on the Dynamic Characteristics of Saturated Sand Mixed Gravel with Different Shapes and Content

作　　者：朱小军[1,2] 贾晓敏 ZHU Xiao-jun;JIA Xiao-min(School of Civil Engineering,Southeast University,Nanjing 210096,China;College of Civil Science and Engineering,Yangzhou University,Yangzhou 225127,China)

机构地区：[1]东南大学土木工程学院,南京市210096 [2]扬州大学建筑科学与工程学院,扬州市225127

出　　处：《公路》2020年第11期306-313,共8页Highway

基　　金：江苏省自然科学基金青年基金项目,项目编号BK20170509。

摘　　要：为了研究掺砾形状对掺砾砂土动力特性的影响,进行了级配相同的亚圆形、棱角形及片状3种形状掺砾砂土的动三轴试验。控制掺砾形状、掺砾量和固结压力等因素,研究掺砾砂土的动弹性模量、阻尼比、孔压及动强度。试验结果表明:掺砾形状对掺砾砂土的动弹性模量影响与围压有关,有效围压小于400kPa时,片状掺砾砂土比棱角形掺砾砂土具有更高的动弹性模量,而亚圆形掺砾砂土动弹性模量最小,当固结压力达到400kPa时,片状掺砾砂土动弹性模量降低至最低;片状掺砾砂土阻尼比最大,而亚圆形掺砾砂土的阻尼比要小于棱角形掺砾砂土;掺砾量在10%~50%范围内,掺砾量越高,掺砾砂土动弹性模量越大,而阻尼比越小。亚圆形掺砾砂土孔压发展最快,而片状掺砾砂土孔压发展最慢;片状形掺砾砂土的动强度最高,棱角形次之,亚圆形最低,且掺砾形状越不规则对动强度的影响越大;掺砾量越高,砾粒之间渗透边界越宽,掺砾砂土孔压消散越快,其动强度相应增大,并且随围压的升高这种趋势越来越明显。In order to study the influence of the granular shape on the dynamic characteristics of sand mixed gravel,the dynamic tri-axial texts are performed on the same gradation of sand mixed gravel,with three different types of gravel:rounded,angular and flake grains.The granule shape,the gravel content and the consolidation pressure factors are controlled to study the effects of sand mixed gravel on the dynamic elastic modulus,the damping ratio,the pore pressure and the dynamic strength.The experimental results indicate that:the influence of granular shape on the dynamic elastic modulus of sand mixed gravel is related to the confining pressure,when the effective confining pressure is less than 400kPa,the sand mixed flake gravel has a higher dynamic elastic modulus than the angular one,while the sand mixed rounded gravel has the lowest dynamic elastic modulus.When the consolidation pressure reaches 400kPa,the dynamic elastic modulus of the sand mixed flake gravel reduced to a minimum.The sand mixed flake gravel has the largest damping ratio,while the damping ratio of sand mixed rounded gravel is less than that angular one.The gravel content within the range of 10%~50%,the higher the gravel content is,the larger the dynamic elastic modulus of gravel sand is,and the smaller the damping ratio is.The pore pressure of sand mixed rounded gravel is developing fastest,while the sand mixed flake gravel developed most slowly.The sand mixed flake gravel has the highest dynamic strength,followed by the sand mixed angular gravel and the sand mixed rounded gravel is the lowest one,the more irregular the gravel shape is,the greater effects on the dynamic strength is.The higher the gravel content is,the wider the permeable boundary condition between gravels is,the faster the pore pressure dissipates,and the dynamic strength increases accordingly,and this trend comes more and more obvious with the increase of the confining pressure.

关 键 词：掺砾砂土 掺砾形状 动弹性模量 阻尼比 动强度 

分 类 号：U414.01[交通运输工程—道路与铁道工程]